Opinions Please - Noise/Slugging on startup

[SonicExplorer]

Hi,

I have a relatively new residential split heat pump (410a/Copleand scroll) system that I've had startup noise issues with since installation. A type of ratcheting/grinding sound that varied in volume and duration depending on conditions (temps, how long between cycles, etc). Today I had the mfr rep finally come out to listen. Overcharge was previously ruled out. So the conclusion was refrigerant migration. He suggested a crankcase heater AND a hard start kit.

A crank case heater, if I did the math right, is going to add some 40KW per month (give or take) on average to the electric bill, which is a 5%-10% increase in the overall electric bill. Bascially wiping out a good portion of any real-life efficiency gains from installing the new system.

Is it possible that one or the other solution would be sufficient rather than both modifications being necessary? I'm not the HVAC expert but I suspect the crankcase heater would have more impact in solving the problem than the hard start kit would ?

I kind of suspect the proposed solution is overly thorough so the problem doesn't need to be addressed again in the future, but I'd like to hear the thoughts of some HVAC experts on the forum.

Thanks,

Sonic

[Shophound]

A few extra kw's per month's a lot cheaper than a dead compressor.

Regardless, a crankcase heater can be installed with a thermostat that will cut it off when outdoor temps rise over 70 degrees. Will save a few pennies during the cooling season (refrigerant migration not as much of an issue in summer when outdoor temps are higher).

Another solution is a liquid line solenoid valve. Shuts flow off in the liquid line whenever the system is not running. It's only drawing power when compressor is on, so it's a normally closed valve.

[SonicExplorer]

Another solution is a liquid line solenoid valve. Shuts flow off in the liquid line whenever the system is not running. It's only drawing power when compressor is on, so it's a normally closed valve.

1) Does this solenoid valve work for both cooling and heating mode? I get the ratcheting noise in both, although granted it seems to be longer/louder in heating mode.

2) What happens if the solenoid fails, does that equate to a fried compressor as if it was being starved (or pumped down into a vacuum state) and it basically nukes itself?

[SonicExplorer]

One other thing...it is totally unclear to my why I am allegedly having migration issues. The recip/piston system previously installed never exhibited any such issues and a recip is WAY more senstive to slugging liquid than a scroll. Any thoughts that might explain why this new system allegedly has migration issues when the other did not? (The previous system was 16 years old and still running fine when I replaced it, so if it had been slugging any liquid the compressor would have almost surely died long before then).

[jpsmith1cm]

hvacmike85

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[catmanacman]

when they install the crankcase heater make sure they install the discharge line thermostat to turn the heater off while the unit is running and also when the temp is above a certain temp not sure of temp , the cch only draws about 65 watts.also I'm sure they are going to use the oe trane start kit I hope. one other thing some times that composit base of the unit can transmit noise ask that the unit be sit on isolation pad

[tinknocker service tech]

if the rep wants a cch and a hard start then let them put it in
this is his job to resolve any iaaues and help the owner live with the unit

[Shophound]

1) Does this solenoid valve work for both cooling and heating mode? I get the ratcheting noise in both, although granted it seems to be longer/louder in heating mode.

2) What happens if the solenoid fails, does that equate to a fried compressor as if it was being starved (or pumped down into a vacuum state) and it basically nukes itself?

Combining liquid line solenoid with pump down on a heat pump might be a bit more tricky.

Upon review I agree with tinknocker...if the rep says go with crankcase heater and hard start kit, do it.

As for why you might have migration issues now when your old unit apparently did not, could be a number of things. Accept that you have it and that the rep gave you a solution.

[Gunnery Sergeant Hartman]

if the rep wants a cch and a hard start then let them put it in
this is his job to resolve any iaaues and help the owner live with the unit

Exactly. No reason to continue searching the web for answers.
Let the manufacturer do their job. If you still aren't satisfied (you probably wont be), ask for your money back and hire a new contractor and choose another brand.

[timebuilder]

I'd like to wonder aloud if this sound is indeed atypical for a scroll, since the previous unit was not a scroll. Is there an audio file of the sound?

Did your contractor install an insulation blanket to muffle sound and keep the compressor warm?

[Stamas]

Heads Up here.
I believe that his refrigerant piping is underground and has had problems with water accumulating in chase.

[SonicExplorer]

Thanks guys for the replies so far.

Stamas the rep verified the way I re-engineered the rain drainage situation is good, he was quite impressed actually. The chase is clear, no more water (I been checking it every month or so just to be sure with a syphon line that I installed permanently). And these noise problems occurred both before and after the chase had water in it, so that's not related.

Compressor already has a blanket.

I'm sure the noise is not normal for a scroll under normal conditions. Otherwise the rep would not be offering to install the kits. What would be the point of doing that work and then not having it resolve things? lol

Maybe what I could do is ask the tech who shows up to please install the hard start kit first and lets see what it does. If it resolves or greatly improves things (by 50% or more) then I'd personally rather not do the crank case heater. Although I suspect the situation is actually the other way around where the crank case heater is the thing that will likely resolve most (or all) of the issue and the hard start kit is not really necessary but rather being overly thorough. That's really all I was asking for opinions on. I like to hear what different experts think, it's good to learn and sometimes new ideas or better solutions surface.

Sonic

[beenthere]

A 40 Watt CCH will never use 40KW in a month.

[hvacrmedic]

A 40 Watt CCH will never use 40KW in a month.

28.8 kwh per month.

[Shophound]

I can't see a hard start kit by itself causing the sound you're hearing to go away.

If there's liquid in the crankcase when the compressor cranks up, the scroll plates will sound like crap until the liquid flashes and/or passes completely out of the compressor.

Do the crankcase heater first, not last, if you're going to approach this thing piecemeal.

[Shophound]

28.8 kwh per month.

$48/year at $0.14 per kilowatt hour. Who's too much of a cheapskate to pop for that amount of compressor insurance? :)

[wahoo]

If it's any consolation, your old piston HP compressor had a crankcase heater and was probably larger than 40 watts!

[SonicExplorer]

My old recip compressor had a crankcase heater?? Really?

I was told this cc heater would consume 80-100 watts. That's 45KWH per month based on my system running an average of 1/3 the time over a 90 day period (meaning the cc heater would be running 2/3 the time). Which is all fact based on the run-time usage tracked by the digital stat (for filter replacement purposes). So with those numbers, it equates to 40KWH-45KWH per month, and that's not trivial. Over a year, that's roughly 500KWH a year - almost $100 in electicity PER YEAR. Over a 15 year span I'll end paying as much in cc costs as a whole new compressor.

Would feel a lot better about this if somebody could explain, or even come up with a likely theory, as to why I never had a migration issue before. It would have fried a recip from what I've been told, so it obviously wasn't happening with the old system. Or else I had a cc heater and did not even know it. I am original owner of a newly built home, so unless the Bryant systems came stock with a cc heater then one wasn't installed.

[beenthere]

barbar, this is the Ask Our Pro's forum, and only Pro members that have been vetted by the AOPC may post advise here. Please apply to the AOPC today, thank you.

You can find the rules for posting and qualifications here (http://hvac-talk.com/vbb/showthread.php?t=957002).




Further infractions may result in loss of posting privileges.

[timebuilder]

I'm sure the noise is not normal for a scroll under normal conditions. Otherwise the rep would not be offering to install the kits. What would be the point of doing that work and then not having it resolve things? lol



Oh, man. That's a red flag for me.

You have a complaint. The guy wants your complaint to end, so he says, "do this."

Now, there are two reasons he may say that:

1) He agrees there is a problem sound, and he believes these actions will end the sound problem.

or

2) He thinks there is a placebo effect, in that you will believe there is a change in the sound, whether that is true or not, following some type of action being taken.

So, I'd like to hear the sound.

[SonicExplorer]

I have sounds but apparently there's no way to post MP3 files on the forum.

Can someone also clarify if a cc heater is applicable to refrigerant migration in both heating AND cooling mode? Because the ratcheting/grinding sounds during spin-up tends to occur in both modes, not just heating. Would refrigerant still want to migrate to the crank case even in cooling mode?

[Shophound]

I have sounds but apparently there's no way to post MP3 files on the forum.

Can someone also clarify if a cc heater is applicable to refrigerant migration in both heating AND cooling mode? Because the ratcheting/grinding sounds during spin-up tends to occur in both modes, not just heating. Would refrigerant still want to migrate to the crank case even in cooling mode?

Make a video and post it on YouTube, then link to it here.

Refrigerant flow through a compressor is the same whether heat pump is in heating or cooling mode.

Refrigerant will migrate to the coldest location when the compressor is off. If that happens to be your compressor crankcase, that is where the refrigerant will go, and condense into a liquid.

For cooling mode, the compressor crankcase tends to run warmer because it's outdoors in the heat, and the suction gas returning to the compressor is warmer in summer than in winter. A thermostat that deactivates the heater when things are warm enough is a good idea.

[Shophound]

However...if you're hearing the sound year round, you mention you have a compressor blanket. That's acting like an insulator. Could be keeping the crankcase colder during warm weather.

Don't take the blanket off. Add the heater. How your lineset is run may or may not be contributing to the problem, but unless there is something mechanically at fault with the compressor scroll plates itself, you need to eliminate any external cause from the equation. Go for the heater, 'nuff said.

[SonicExplorer]

Thanks Shophound, it gets darn warm here in FL Summers and even yet I still get the ratcheting sound during cooling mode. The thing I've noticed that does effect things though is how long between cycles. If the unit is cycling every 15 minutes or so it won't tend to make the noise as much but whenever it sits for an hour or more (or especially ifit has been not cycled for hours) that's when the noise will DEFINITELY happen.

AHU/Evap is on a platform about 3 feet higher than the compressor and the lineset runs about 25 feet under ground, soft v-shape where the center reaches a depth of about 3 feet below ground level before working its way back up. So it's kind of like a long, gradual oil-trap. But again keep in mind it is the same lineset my old R22 system was connected to and it NEVER made these rediculous noises.

[beenthere]

CCH can help to prevent migration in both heating and cooling season.

[catmanacman]

You want a solution to your situation then when one is given your not happy with it

[JWB]

Scroll's are loud. I have been on many of these calls. Scrolls are very reliable. The manufacurers aren't idiots, but the customer loves to stand there year after year and tell techs that it isn't right. Meanwhile the compressor keeps running. Good luck with this one.

[catmanacman]

when they install the crankcase heater make sure they install the discharge line thermostat to turn the heater off while the unit is running and also when the temp is above a certain temp not sure of temp , the cch only draws about 65 watts.also I'm sure they are going to use the oe trane start kit I hope. one other thing some times that composit base of the unit can transmit noise ask that the unit be sit on isolation pad

I remember you have a carrier not a trane

[timebuilder]

I have sounds but apparently there's no way to post MP3 files on the forum.

Can someone also clarify if a cc heater is applicable to refrigerant migration in both heating AND cooling mode? Because the ratcheting/grinding sounds during spin-up tends to occur in both modes, not just heating. Would refrigerant still want to migrate to the crank case even in cooling mode?

Correct.

However, other equip owners have posted a video on youtube and posted a link here so we can listen. It's not the first time we have heard the "my unit makes a noise" complaint. :angel:

[timebuilder]

Thanks Shophound, it gets darn warm here in FL Summers and even yet I still get the ratcheting sound during cooling mode. The thing I've noticed that does effect things though is how long between cycles. If the unit is cycling every 15 minutes or so it won't tend to make the noise as much but whenever it sits for an hour or more (or especially ifit has been not cycled for hours) that's when the noise will DEFINITELY happen.

AHU/Evap is on a platform about 3 feet higher than the compressor and the lineset runs about 25 feet under ground, soft v-shape where the center reaches a depth of about 3 feet below ground level before working its way back up. So it's kind of like a long, gradual oil-trap. But again keep in mind it is the same lineset my old R22 system was connected to and it NEVER made these rediculous noises.

Okay, Shophound mentioned the youtube thing, too. Good.

Did you get both units replaced, the condensing unit and the airhandler/coil?

What else is different? Did the old indoor part use a txv or a fixed metering device? Is this the old lineset, or a new lineset installed in the same way?

Usually, when oil is "trapped" it means that the oil cannot get from a low mounted evap back up the suction line to a high-mounted condensing unit. That is the opposite of what you have here. The oil will entrain just fine, unless there is a vast difference in height (like 50 feet), and in heating mode.

What did your contractor say and do when you first asked about this?

[Shophound]

I still would not rule out an overcharge, even if those who have looked at the system say otherwise.

Why? It's a learned skill to get a system charged correctly. Too often the approach is "pressures look good" and the tech moves on. Without superheat and subcooling readings taken, and knowing how to interpret them, the charge can be off in any given system easily.

An overcharged system with a scroll, particularly with a piston or a TXV that allows the system to equalize in the off cycle, in my experience can make the "grunt" or "grind" sound when the compressor first cranks up. Came across that last summer, more than once. Adjusted the charge and the sound disappeared. One of these systems was a heat pump. Other straight cooling.

[Mr Bill]

I don't think your going to stop the noise, I have seen some that never stop, hey maybe stick you a suction line accumulator on there. :grin2:

[SonicExplorer]

I still would not rule out an overcharge, even if those who have looked at the system say otherwise.

Why? It's a learned skill to get a system charged correctly. Too often the approach is "pressures look good" and the tech moves on. Without superheat and subcooling readings taken, and knowing how to interpret them, the charge can be off in any given system easily.

An overcharged system with a scroll, particularly with a piston or a TXV that allows the system to equalize in the off cycle, in my experience can make the "grunt" or "grind" sound when the compressor first cranks up. Came across that last summer, more than once. Adjusted the charge and the sound disappeared. One of these systems was a heat pump. Other straight cooling.

I agree entirely because the system was not making these noises for the first few months until they did an evap TXV swap (that turned out to be unecessary as another noise problem at shut down was due to water in the chase causing a hammering sound in the liquid line). Immediately that night after the TXV swap the noises began. Which is why I'm very concerned, rightfully so, that the suggestion of a cc heater is just putting a band aid over some other underlying problem.

The original installers checked charge twice using subcool method and said it was dead on. Even though I'm no HVAC expert, what I would like to see happen before installing a cc heater is to simply weigh out a small amount of charge (1/2 lb or 1 lb) and see if it resolves the problem. If not, then simply replace it, no harm. At least that approach would truly rule out an overcharge. Seems like a pretty quick, logical and inexpensive test. No ?

[beenthere]

The original installers checked charge twice using subcool method and said it was dead on. Even though I'm no HVAC expert, what I would like to see happen before installing a cc heater is to simply weigh out a small amount of charge (1/2 lb or 1 lb) and see if it resolves the problem. If not, then simply replace it, no harm. At least that approach would truly rule out an overcharge. Seems like a pretty quick, logical and inexpensive test. No ?

No, its not.

[timebuilder]

I agree entirely because the system was not making these noises for the first few months until they did an evap TXV swap (that turned out to be unecessary as another noise problem at shut down was due to water in the chase causing a hammering sound in the liquid line). Immediately that night after the TXV swap the noises began. Which is why I'm very concerned, rightfully so, that the suggestion of a cc heater is just putting a band aid over some other underlying problem.




Now look at that. Relevant information.

1) Did the service manager have any explanation for this sudden change after a basic parts replacement, and 2) what were they trying to accomplish? Did the txv's have identical part numbers?

[catmanacman]

I'm thinking they should recover all refrigerant change drier vac to about 250 microns and weight the exact amount of refrigerant .and install the crancase heater ,I believe all heat pumps should have a crankcase heater.

[Shophound]

The original installers checked charge twice using subcool method and said it was dead on. Even though I'm no HVAC expert, what I would like to see happen before installing a cc heater is to simply weigh out a small amount of charge (1/2 lb or 1 lb) and see if it resolves the problem. If not, then simply replace it, no harm. At least that approach would truly rule out an overcharge. Seems like a pretty quick, logical and inexpensive test. No ?

"Dead on" means nothing to me and anyone else reading this thread. Data is what matters. Outdoor dry bulb temperature, indoor dry and wet bulb temperatures, suction and discharge pressures, liquid line temperature, suction line temperature, all measured close together regarding time. That's minimum data required to determine if your system is even close to "dead on" or not.

Your idea to arbitrarily "weigh out" 1/2 to 1 pound of refrigerant is not a good one by itself. If "weighing out" a pound of gas happens to coincide with nailing the correct charge via good subcooling and superheat readings, so much the better. But the amount weighed out is coincident, not the template to use for bringing the charge in line.

[SonicExplorer]

Shophound, points taken. All I can share about checking the charge was that they did measure line temps and pressures and cross-referenced that with the chart. I saw them do that much. And Delta T. The reason I tossed out the notion of removing some charge as a simple test is that if the system is overcharged it cannot be by much, based on what they said they added. However, again, we are dealing with an installing company and techs that clearly either do not fully understand what they are doing or chose to cut corners, so I guess whatever I've been told should not be taken as accurate.

The reason the original TXV was swapped out is, as was mentioned early on in the post, because there was a lot of water in the chase that was causing an equalizing issue at shutdown that manifested itself as knocking in the liquid line near the AHU. The installing company, in all their idiocy, was too inept to even check line temps which would have easily told them there was massive temp loss between inside and outside units and pointed them right at the area where the problem lie. Instead, they insisted it was a problematic TXV and swapped it out (using what they claimed to be an exact mfr replacement part...and it does at least look identical). Ever since that procedure the compressor has been making the grinding/ratcheting noises at startup (to varying degrees basd on a variety of conditions).

And yes, I am 10000% certain the system did not make the noises before the TXV swap. Why? Because I was listening to and inspecting everything imaginable trying to help narrow down why the liquid line was knocking on shutdown. In fact, I was extremely happy and impressed by how quiet the system was, starting and running, etc. Now, the thing makes racket starting and even has a low level, subtle thrum inside the home that did not exist before the TVX procedure.

FINALLY, I got the mfr rep to come out the other day and his recommeded solution was cc heater and hard start kit. And I'm not disagreeing with that notion being a potential solution, but I am very much suspect that may be just putting a band-aid on an underlying issue, or there may be a better way to go about this. So before I go jumping into something, I wanted to get some feedback from you guys on the forum...to get any ideas or suggestions that I could run by the rep if necessary before I approve any more service work.

Sonic

[Shophound]

Understand where you're coming from better, now. Some here may view you as a PITA type customer but at the same time you're the one that must live with this system, and you're the one that will be inconvenienced if the thing dies at the worst possible time.

Not saying you're headed that way, of course. But I don't like to hear compressors make strange sounds any more than you do. Mechanical equipment make strange sounds when things aren't right...over and over again in my career I've seen that.

Stepping back to the water in the lineset chase issue; I take it from that point is where the TXV was installed to resolve some form of "hammer" issue that occurred what...when the system shut off or started up? And immediately afterward the "hammer" issue went away but the "grind" at compressor start-up began?

Also, you have since resolved the standing water in the chase issue, correct? Was this resolved prior to the TXV going in or afterward?

[SonicExplorer]

Understand where you're coming from better, now. Some here may view you as a PITA type customer but at the same time you're the one that must live with this system, and you're the one that will be inconvenienced if the thing dies at the worst possible time.

Not saying you're headed that way, of course. But I don't like to hear compressors make strange sounds any more than you do. Mechanical equipment make strange sounds when things aren't right...over and over again in my career I've seen that.

Stepping back to the water in the lineset chase issue; I take it from that point is where the TXV was installed to resolve some form of "hammer" issue that occurred what...when the system shut off or started up? And immediately afterward the "hammer" issue went away but the "grind" at compressor start-up began?

Also, you have since resolved the standing water in the chase issue, correct? Was this resolved prior to the TXV going in or afterward?

When the system was initially installed it was making a hammering noise in the liquid line right at the AHU right when a heat cycle shut off. The installer could not figure what the cause was and then declared it must be a faulty evap TXV. So they replaced it. It did not solve the problem, but it DID introduce the condensor noises I'm now suffering. Anyway, shortly after the TXV swap, the mfr rep came out and immediately determined the knocking was due to a lot of water in the chase - which was screwing up the normal equalization process that takes place and manifesting itself as knocking. I cleared and sealed the chase and the knocking was resolved, the chase remains bone dry (I left a syphon line it to check occassionally) but now I am still suffering from the compressor noises.

[marvin]

you need to see your md & get a scrip for valium 10
& the noise wont bother you anymore. you are worrying that unit
to death.

[Mr Bill]

you need to see your md & get a scrip for valium 10
& the noise wont bother you anymore. you are worrying that unit
to death.

http://i99.photobucket.com/albums/l286/mrbillpro/1.gif

[SonicExplorer]

you need to see your md & get a scrip for valium 10
& the noise wont bother you anymore. you are worrying that unit
to death.

Real professional reply. You should go apply with the company who installed my system.

Seriously though, worrying has nothing to do with it, the friggin' thing is waking me all night long. Pretty soon I'm going to take a shotgun to it and put it out of ALL our misery. :censored:

[Mr Bill]

Pretty soon I'm going to take a shotgun to it and put it out of ALL our misery. :censored:

http://i99.photobucket.com/albums/l286/mrbillpro/icon_worthless.gif

[Shophound]

When the system was initially installed it was making a hammering noise in the liquid line right at the AHU right when a heat cycle shut off. The installer could not figure what the cause was and then declared it must be a faulty evap TXV. So they replaced it. It did not solve the problem, but it DID introduce the condensor noises I'm now suffering. Anyway, shortly after the TXV swap, the mfr rep came out and immediately determined the knocking was due to a lot of water in the chase - which was screwing up the normal equalization process that takes place and manifesting itself as knocking. I cleared and sealed the chase and the knocking was resolved, the chase remains bone dry (I left a syphon line it to check occassionally) but now I am still suffering from the compressor noises.

Note where I've put words in your quote above in bold. They're distinct clues.

First of all, when a heat pump is in heating mode, the indoor TXV does not meter refrigerant. It allows liquid refrigerant to flow in the opposite direction to what it would be doing in the cooling mode. In the cooling mode, the indoor TXV meters refrigerant. In heating mode the indoor TXV will only begin metering refrigerant once refrigerant flow is reversed, such as during a defrost call.

That you state replacement of the indoor TXV did not resolve the hammering problem does not surprise me, considering you stated the hammering problem occurred in the heating mode, not the cooling mode.

As for why water in the chase was causing the hammering to occur, my best guess is that while the heat pump ran, it heated the water in the chase that surrounded the liquid line (in heat pumps, the liquid line remains what it is called in straight a/c, but the suction line name is changed to "vapor line"). When the compressor stopped, liquid refrigerant in the liquid line flashed into vapor due to being surrounded by hot water and the reduction of pressure internally once the compressor stops. The sudden flashing of refrigerant pushed aside remaining liquid until it hit one of the metering devices and slammed into it.

But that's just my guess. Only way to give it more stick would be via measuring the temperature of the water trapped in the chase.

All that now aside, your present problem I believe remains to be an overcharge. You have three choices: either keep riding herd on your installer to resolve the noise issue, find a different tech not associated with your installer to diagnose the problem, or enroll in a trade school/community college HVAC program, buy some tools, and get your EPA cert so you can adjust the charge yourself. If you choose this route, you'll be surprised by how much it costs both in time and money.

Adding crankcase heat won't hurt anything...the old fellow who mentored me in HVAC when I was a teenager insisted on putting one on every compressor he changed out or had a experienced a history of problems. He did that when he changed out my parent's Lear-Siegler condensing unit in 1973...it ran for 27 years before the new homeowners changed the condenser out because they had enlarged the house.

What that means is that even a properly charged system can experience refrigerant migration to a cold compressor crankcase. A heater is CHEAP insurance to long compressor life. If our old Lear-Siegler unit was still around you could ask it. :)

[timebuilder]

After reading the recent posts, something has occurred to me.

The unit was installed, and hammered immediately, yes?

The hammering could have been associated with a set of dynamics that actually PREVENTED the compressor from making the noise you are now hearing. In other words, had the lineset not have been in a chase full of water, it IS possible that you would have heard the compressor noise from day one. Fixing the lineset issue may have only created a normal condition for your unit to begin making the noise.

And I still want to hear the noise.

[tinknocker service tech]

the rep said cch was needed and a hard start and 5 days later we are talking about maybes
start there if it doesnt work then there is something to talk about

we also need some real info
pressures temps and amps on startup
anything else is just talk with no real info to back it up
had the work done and stop worying about the cost of the heater
100 dollars a year isnt worth talking if it solved your troubles
most units have then and noone knows it

[superfittertech]

Your old heat pump definitely had a crankcase heater as then that was always standard equipment as a reciprocating compressor would not last very long with liquid in the crankcase nor could it handle any liquid slugging.

[timebuilder]

Let's hear the noise.

[superfittertech]

Let's hear the noise.

x2

[SonicExplorer]

Timebuilder, the TXV was swapped BEFORE I removed the water from the chase. So the water in the chase had no relationship to the start-up noises surfacing immediately after the TXV swap. A few weeks after the proper diagnosis for the knocking was made, I removed the water from the chase, and doing so stopped the knocking. But it had no impact on the startup noise that surfaced immediately following the TXV swap.

Let me ask you guys a question... is there any chance the TXV was damaged during install and that is why refrigerant is being allowed to migrate back to the compressor during off cycle? Because one thing that happend during the TXV swap was the little capillary line that comes from the TXV and goes to the side of the suction line presented a challenge. The tech had to braze about a dozen times to finally get it into the suction line, so he really nuked the heck out of things. If there is any kind of plastic parts or valves inside that TXV that are involved in refrigerant migration during the off-cycle, then they might have been damaged. And at no time did the guy use a wet rag to help protect the TXV. Probably a long-shot, but thought I'd at least mention it.

As for the overcharge theory, the one thing that doesn't quite add up is the tech pumped down the system for the TXV swap and did not add nor remove any refrigerant, he simply opened back up the system after a vacuum. Since the noises did not occur before that procedure, yet began immediately afterwards, it's not obvious how an overcharge could suddenly be the culprit. Unless he added more refrigerant that I didn't see, but that's a bit doubtful.

I'd post sound files but I have no place to post them and have no plans to open social networking accounts just for that. I hate computers. lol If there's some way to post a sound file on the forum I'll be glad to do so. :D

[barbar]

First to find out is are you getting liquid migration or flood back.
1; When the system is running (say after 20mins) is the compressor body (not the top) warm/hot or is coolish to warm? J
2; If the comp is warm/hot when running, when it turns off, after 5 mins is the compressor much colder, or about same?
(make sure the comp wrap is on)
It is very normal for scroll to have a banging noise on start up. When the off the internal parts are not meshed. On Start up they "smash" together (slightly wrong word but helps explain) You tend to find the longer it is off the greater the noise., this due to the coating of oil on the scrolls (over time the old drains back into the bottom of the compressor)

[timebuilder]

I'd post sound files but I have no place to post them and have no plans to open social networking accounts just for that. I hate computers. lol If there's some way to post a sound file on the forum I'll be glad to do so. :D

Ask a friend to post the file on youtube. Post a link to that page.

That's the only way you can get advice on a noise.

[jpsmith1cm]

There is another option.

Now, you claim to hate computers, so you may not have the computer savvy to pull this off, but here goes.

Take a short video of the unit operating and making the noise.

Download the video to your PC.

Upload that video to a file sharing website like the recently defunct MegaUpload. There are many legit sites like Box.com that will do this for free.

copy and paste a link here.

[Shophound]

the one thing that doesn't quite add up is the tech pumped down the system for the TXV swap and did not add nor remove any refrigerant, he simply opened back up the system after a vacuum.[/B] Since the noises did not occur before that procedure, yet began immediately afterwards, it's not obvious how an overcharge could suddenly be the culprit. Unless he added more refrigerant that I didn't see, but that's a bit doubtful.





Regardless, get the crankcase heater installed anyway. Every day you dither on the thing is another day your compressor is throwing metal shavings into the refrigeration circuit. Do you think that's a good idea?

[Mr Bill]

As for the overcharge theory, the one thing that doesn't quite add up is the tech pumped down the system for the TXV swap and did not add nor remove any refrigerant, he simply opened back up the system after a vacuum. Since the noises did not occur before that procedure, yet began immediately afterwards, it's not obvious how an overcharge could suddenly be the culprit.

"IF" the old valve was bad and "maybe" stuck wide open, well it could have been overcharged from the get go, and that means it's really overcharged now. You sure you or a buddy are not the techs? :whistle:

[tinknocker service tech]

Timebuilder, the TXV was swapped BEFORE I removed the water from the chase. So the water in the chase had no relationship to the start-up noises surfacing immediately after the TXV swap. A few weeks after the proper diagnosis for the knocking was made, I removed the water from the chase, and doing so stopped the knocking. But it had no impact on the startup noise that surfaced immediately following the TXV swap.

Let me ask you guys a question... is there any chance the TXV was damaged during install and that is why refrigerant is being allowed to migrate back to the compressor during off cycle? Because one thing that happened during the TXV swap was the little capillary line that comes from the TXV and goes to the side of the suction line presented a challenge. The tech had to braze about a dozen times to finally get it into the suction line, so he really nuked the heck out of things. If there is any kind of plastic parts or valves inside that TXV that are involved in refrigerant migration during the off-cycle, then they might have been damaged. And at no time did the guy use a wet rag to help protect the TXV. Probably a long-shot, but thought I'd at least mention it.

As for the overcharge theory, the one thing that doesn't quite add up is the tech pumped down the system for the TXV swap and did not add nor remove any refrigerant, he simply opened back up the system after a vacuum. Since the noises did not occur before that procedure, yet began immediately afterwards, it's not obvious how an overcharge could suddenly be the culprit. Unless he added more refrigerant that I didn't see, but that's a bit doubtful.

I'd post sound files but I have no place to post them and have no plans to open social networking accounts just for that. I hate computers. lol If there's some way to post a sound file on the forum I'll be glad to do so. :D

pulled a few txvs apart to see why they woudnt work and there are no plastic parts and they can handle more heat then you may think
the equalizer tube you are discribing is just a small copper tube
now my concern after readings this whole tread again is the fact your linestet is running 25ft under ground and at a depth of 3ft. There is a big temp difference and is possible to cause a major migration problem when in the off mode summer and winter. Your old unit didn't seem to have a problem because IT DID have a crank case heater and liquid in the compressor was not allowed to be present.
Now you have a scroll witch can pump liquid for short periods of time because the plate will spread allowing room for the liquid but the plate will hit on the opposite side causing a noise. Now you are finding a heater is in fact needed to resolve this problem and the reason is the under ground pipes

you may also be over or under charge if the temp difference is affecting the readings and line temps at the condenser. What is the line temp at the evap coil and the condenser. If the difference is great then you have an answer and the rep can help with a resolution


there is also one last possible thing
if the tech pumped the refrigerant back and pulled the compressor into a vacume witch you shouldnt do with a scroll he may have damaged the plate to some extend causing the noise witch will require a new compressor
all other posibilities need to be ruled out first before the last route mentioned can be explored
put in the heater asap

[Mr Bill]

if the tech pumped the refrigerant back and pulled the compressor into a vacuumed which you shouldnt do with a scroll he may have damaged the plate to some extend causing the noise witch will require a new compressor.

Good catch! yes I never go below 20 psi with any Scroll.

[SonicExplorer]

Barbar, I can't reach the compressor to feel the temp, and it's under a blanket of some sort as well.

You other guys are describing exactly what I have feared all along but have not mentioned yet: That the tech may have damaged the compressor during pump down. Prior to the service I read the manual to learn about what a pump down is and I warned the tech to be darn sure he did not pull it into a vacuum. The installing company is so CHEAP, just to give you an example they re-used the same piece of insulating tape on the TXV bulb, which subsequently opened back up a few days later and I had to go repair myself. So you can bet the tech was not about to let one ounce of referigerant escape when opening the system, heaven forbid they had to pay to replace it. They had previously added about 10 ounces to the standard charge the system comes with (for a 15 foot lineset). So I don't know if that is any clue that too much refrigerant might have been pumped back in or what, it's all over my head. Or does the fact not one ounce of refrigerant was added after pumpdown provide a clue he probably pulled it into a vacuum? This goes right to why I am very worried that we may be just putting a band-aid on things with a cc heater. Not only does the compressor make startup noises, it also "thrums" now, very mild low frequency hum - but annoying enough to be heard in some areas of the house - and that definitely started the night of the TXV swap as well. I know compressors can make these noises, but I'm a million percent sure they did not exist audibly inside the home until after the TXV swap.

So here's another critical question: Let's assume the compressor might be damaged form pump-down. If I have a cc heater and hard start kit put on it, will it keep making the noises, thereby confirming likely compressor damage instead of migration? Or will we just be potentially covering up the noises of a damaged compressor?

[tinknocker service tech]

So here's another critical question: Let's assume the compressor might be damaged form pump-down. If I have a cc heater and hard start kit put on it, will it keep making the noises, thereby confirming likely compressor damage instead of migration?


yes if the plate was damaged then there is no quick or easy fix
if the heater works then the plates are not dameged.
you most likely will have the grinding noise the whole time the compressor is running not just at startup
migration is common and IMHO all compressors should have a heater but the scroll is the one compressor that can pump liquid with out any harm so it is left out when the manufactures put it in and only used on an as needed bases
in your case since the noise is bothersome then it is needed
hard start kit IMP will have little or no difference

[jpsmith1cm]

I, for one, DO NOT buy the idea of a damaged compressor during pumpdown.

The problem with running scrolls in a vacuum is that they can pull down SO fast that they can cause a deep enough vacuum to arc and damage the windings.

Pumping down a scroll won't damage it. I do it all the time and mine still purr.

[Gunnery Sergeant Hartman]

I still don't know why the OP hasn't just asked to have the system removed and money refunded. I'm pretty sure the installing contractor would be more than happy to do this.

Sonic will worry the system to death. When it does fail (in 15+ years), he'll be pointing at the "incompetent installers"...

[mlstark]

I don't know how this thread has gone over 60 posts, and the op has over 500 posts talking about his crappy system.:whistle:

[Shophound]

I, for one, DO NOT buy the idea of a damaged compressor during pumpdown.

The problem with running scrolls in a vacuum is that they can pull down SO fast that they can cause a deep enough vacuum to arc and damage the windings.

Pumping down a scroll won't damage it. I do it all the time and mine still purr.

I don't buy it, either. What I understand about scrolls and pump downs is that if they go into a vacuum, the dielectric resistance between the motor windings break down and the windings begin arcing and shorting out.

What I'd want to know is if the OP's "TXV swap" was like for like.

[Mr Bill]

From a Copeland PDF.

Deep Vacuum Operation
Copeland Scroll compressors (as with any refrigerant compressor) should never be used to evacuate a refrig-eration
or air conditioning system. The scroll compressor can be used to pump down refrigerant in a unit as long as the
pressures remain within the operating envelope shown in Fig. 16. Low suction pressures will result in over-heating of
the scrolls and permanent damage to the compressor drive bearing. An internal protection device un-loads and stops
the compressor pumping when the pressure ratio exceeds approximately 10.

[timebuilder]

I still want to hear the sound.

[Mr Bill]

I still want to hear the sound.


What sound? I don't hear any sounds. :grin2:

[timebuilder]

What sound? I don't hear any sounds. :grin2:


Neither do I!

I'd like to think that this unit is doing something that is truly unusual.

BUT, I want to determine that for myself.

[tinknocker service tech]

i want to find out how the cch worked out
i believe it is migration and the op is trying to find away to not have to pay for the usage with isnt enough to even talk about:gah:


s scoll yes will burn the winding if pulled into a deep vacume but also you can damage the bearing or the orbiting dic plate in some cases

[timebuilder]

I still want to hear the sound that started all this.....

:toetap:

[hvacvegas]

I, for one, DO NOT buy the idea of a damaged compressor during pumpdown.

The problem with running scrolls in a vacuum is that they can pull down SO fast that they can cause a deep enough vacuum to arc and damage the windings.

Pumping down a scroll won't damage it. I do it all the time and mine still purr.

I thought copeland had an internal vacuum shutdown anyways.

[timebuilder]

Where is that sound file? :whistle:

[jpsmith1cm]

I thought copeland had an internal vacuum shutdown anyways.

They have an internal relief, but not a "vacuum shutdown". That would require a pressure switch of some sort.

The relief kicks in at something like 11:1 compression ratio. Could easily relieve before you go into a vacuum.

[hvacvegas]

They have an internal relief, but not a "vacuum shutdown". That would require a pressure switch of some sort.

The relief kicks in at something like 11:1 compression ratio. Could easily relieve before you go into a vacuum.

Right, so it's not able to pull into a vacuum....

[jpsmith1cm]

Right, so it's not able to pull into a vacuum....

Yes, they are.

I've done it.

[beenthere]

I believe some of the newer ones have been made that they don't pull into a vacuum.

[timebuilder]

Sound file??????

[Stamas]

http://www.youtube.com/watch?v=dTCNwgzM2rQ&feature=related

[ambarton]

Thanks Shophound, it gets darn warm here in FL Summers and even yet I still get the ratcheting sound during cooling mode. The thing I've noticed that does effect things though is how long between cycles. If the unit is cycling every 15 minutes or so it won't tend to make the noise as much but whenever it sits for an hour or more (or especially ifit has been not cycled for hours) that's when the noise will DEFINITELY happen.

AHU/Evap is on a platform about 3 feet higher than the compressor and the lineset runs about 25 feet under ground, soft v-shape where the center reaches a depth of about 3 feet below ground level before working its way back up. So it's kind of like a long, gradual oil-trap. But again keep in mind it is the same lineset my old R22 system was connected to and it NEVER made these rediculous noises.

I did'nt think Carrier liked underground lines. I have read many articles on this and listened to both sides of the argument. Some say CCH's work and some say they don't. Depending on the situation I agree with both to some degree. A CCH keeps the compressor warm so that refrigerant wont pool in the crankcase but what happens is that it just finds another place that's cooler and it pools there, aka underground. So when the comp fires up it gets a big drink of pure liquid. I would try heat tapeing the underground lines.

[timebuilder]

I did'nt think Carrier liked underground lines. I have read many articles on this and listened to both sides of the argument. Some say CCH's work and some say they don't. Depending on the situation I agree with both to some degree. A CCH keeps the compressor warm so that refrigerant wont pool in the crankcase but what happens is that it just finds another place that's cooler and it pools there, aka underground. So when the comp fires up it gets a big drink of pure liquid. I would try heat tapeing the underground lines.

Easy enough to pipe in an accumulator if this is a "big deal," along with installing a CCH.

I still want to hear the sound file!!!!!!!

[ambarton]

Easy enough to pipe in an accumulator if this is a "big deal," along with installing a CCH.

I still want to hear the sound file!!!!!!!

I think that's a heat pump so it should have one already. You can't pipe accumulators in series.

[catmanacman]

Im curios if the crankcase heater solved the problem should ave been installed bu now

[timebuilder]

I think that's a heat pump so it should have one already. You can't pipe accumulators in series.


I'm not going back to read the whole thing. I recall that an accumualtor was talked about to prevent slugging. :angel:

I want to hear the sound!!!!!!

[timebuilder]

Maybe I should "occupy the noise thread!"

[timebuilder]

:toetap:

[mark beiser]

Sooo, off topic a little bit, back when the TXV and coil were changed, did they replace the filter drier, and purge nitrogen through the lines while brazing it in?

[jpsmith1cm]

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