My parents were a victim of a blow and go

[dave and julie]

We had a hot week a couple weeks back and at some point my mom noticed the a/c wasn't working very well anymore. She made the call for service on their 14 year old Bryant, they said they would come out the next week. Turns out it was a bad fan motor in the condenser. My dad replaced that himself to get it working again. Since they already had the appointment they decided to keep it, even though the system was working, and use it to get a check up.

Here's the scary part. I asked my mom what the tech said about their system. She said they told her it was low on charge and they had to add freon. I asked my mom "where did it go"? These guys apparently convinced my parents that over time the freon leaks out through "pores" in the metal. I said b.s., if you're low on charge it went somewhere, you have a leak and the leak needs to be fixed.

One more thing they said that scared me was that the system was "25% low on charge". They must have vacuumed the system down and weighed it right? I doubt it. You can't know how much volume a given system has and then derive a percentage can you? Aren't they all going to be different due to line set sizes and lengths? And if it was really 25% low on charge, wouldn't that have caused other problems like coil freeze ups, as well as possibly slugged the compressor?

I couldn't convince my parents they recieved poor service. They think it is normal for charge to just disappear over time even though I told them it a system is done right it should never need freon to be added.

[stevehvac]

Well since the system was cooling fine until the fan went and was fine again after it was fixed I dont think this was a blow and go. I think it was not low on freon and probably has no leak. This was a Bill and Go call.The owner probably feels they can make an easy 20-30 bucks per call by "topping" off the freon on those type of calls.

[DeltaT]

You may be right or you may be wrong. Point is is your parents are happy. Why are you trying to make them unhappy?

Communication is a funny thing. It is very possible that the tech attempted to explain to them in terms fitting to a non-tech person that systems do get or have pores in them that leak. Most old systems do. Most systems have little leaks around service valves, old and cracked joints, etc. The time spent trying to find a very small leak is too costly to the customer until that leak become bigger and tracable.

Maybe the tech was wrong...but your parents are still happy and cool, I hope. I would not make a federal case out of this just to be right. But it does certainly give you reason to watch the system and overlook any further service if that would make you satisified.

[Jultzya]

...there are several things you seem NOT to be familiar with.

#1 Metal and braze joints do have pores. Whether they are large enough to cause problems is a different point.

#2 Depending on the size of leak, it 'may or may not' be cost effective to fix and repair the leak. (although, I do prefer to find/repair them)

#3 '25% low...' That can be an easy... What is the total system charge? Then if they weighed the amount (like they should have). They could easily figure out what percentage that is of the total charge. They would first have to make sure 'everything else' with the system is correct.

#4 Line set lengths normally change the charge by oz NOT lbs.

#5 'Low on charge causing problems...' Would all depend on conditions and run times.

#6 'Low on charge cause slugging...' No possible way. Do you know what slugging means???

#7 'I told them it a system is done right it should never need freon to be added...' I think this is the only thing you should assume to be correct in your post! :D
(although a couple of oz in a system in 18-20 years can be achieved due to hose connecting/disconnecting)

[dave and julie]

That's why I posted, to see what you opinions are. So it doesn't seem to be a big deal. I just thought 25% seemed like a lot to lose and not hurt anything.

I'm not an hvac person, just something I'm interested in learning about even though I never plan to actually work on any equipment. I always thought when you ran low on charge you risked a coil freeze up, then you would get liquid back to the compressor and that was called slugging since you can't compress a liquid.

[DeltaT]

Maybe this will help you in your desire to understand all the possibilities.

The condenser fan motor was bad which meant the head pressure went very high. Any leak of any size in the high side of the system would now become bigger as the increased pressure would drive out more refrigerant then would happen during normal head pressure with a properly operating condensor fan motor. Or the increased head pressure worked against the walls of the old and very thin copper and created a small leak.

So when the tech got there he found that problem which would most likely not have been the main problem previous to the failed condensor fan motor hence no coil freezing or major loss of cooling previous to this event.

Everything in these systems are dynamic. One failure can cause other problems in the system. When the head pressure went up the amp draw from the compressor increased which could now have set up a furture failure at the marginal contactor points or a failure at any loose wiring terminals anywhere within the system on the line voltage side.

Or the compressor, old and loose, is now on the way out due to that extra load on the bearing, electrical winding, run capacitor, compressor terminals, etc, etc.

So don't be surprised if a new problem arrives from this call which may show up in the next weeks or, especially, when the temperatures are the hottest and the system is under the heaviest load.

[dave and julie]

That's very true, I didn't think of the head pressure magnifying any leaks that might have been there, or having even created new ones. At least now it makes sense to me, which is why I posted. Thanks!

[Edited by dave and julie on 06-22-2005 at 03:45 PM]

[Jultzya]

Now go tell your parents that you learned something today and that the company servicing the equipment could have very well been on the up and up. :D

[RoBoTeq]

Also, over time and especially after an adverse condition such as the condenser fan not operating, the system can simply change as to its function with the amount of refrigerant that is in it.

There are many reasons for refrigerant to be low. Because weighing in of refrigerant requires that all components be perfectly matched, exact length of refrigerant lines be known and all mechanical components be operating within manufacturers specifications, I much prefer all systems be checked by superheat and subcooling.

In other words, there could be exactly the proper amount of refrigerant in a system that the manufacturer originally required and the system charge could be off due to reasons not calculated by the manufacturer.

[HVAC Pro]

Your parents 14 year old Bryant system has likely reached/or may very well be approaching it's normal life expectancy. Would you have felt better if they had coaxed your parents into spending several hundred dollars to repair a leak in this dinosaur? Sounds like they were looking out for your parents best interests to me.

Doing this day in and day out increases a sharp technician's awareness on when to suggest investing in expensive repairs and when to take a wait and see attitude. The same rules don't always apply to each and every system. Glad to hear the system is back on line.

[beenthere]

No size of unit or line set info means we don't know how much charge it should have.(25% sounds alot, but not out of the ordinary).

maybe it was 10% low and the tech stretched the truth(bad on him).

Maybe it wasn't low at all(no way we can tell).

Just check in with your parents once in awhile to make sure everything is ok.

We all hope they weren't taken advantage of.

Congrats on being children concerned about their parents welfare.

[Freezeking2000]

I have seen refrigerant blow out of schrader valves,when a condenser fan motoe goes bad.

[Mr Bill]

My parents were a victim of a blow and go

I was a victim of that 31 years ago and it's been costing me ever since. :D

[dave_slo]

Originally posted by mrbillpro
My parents were a victim of a blow and go

I was a victim of that 31 years ago and it's been costing me ever since. :D

So was Monica. :)

[Jultzya]

Here's a link (http://www.edwin-fine.com/air_con/index.html) I was thinking about, when the idea of a 'small leak' happening over time was meantioned.

[Irascible]

I think your suspicions are entirely reasonable Dave. The effect that low refrigerant has on performance is not linear. In other words, a charge that's low by 25% would most likely affect performance by more than 25%. If the system was that low it's highly unlikely that your dad would have been happy with its performance after he replaced the fan motor. And in the unlikely event that your dad was happy with its performance while it was that low then the “pores explanation” is a copout. The tech should have been looking for leaks or should have scheduled a time to come back and look for them.

The odds that the tech was being technically precise as exemplified by jultzya or that he had Delta's desire to not confuse are pretty freakin low. It's much more likely that he's a typical hack padding the bill. The propensity of hacker AC guys to add a little Freon to pad the bill has been documented over and over again by investigative journalists. If so, the system is now overcharged. Its efficiency is down and so too will be its life expectancy. OR... It may be that the system was just a smidge low so he added a smidge but characterized it as more in order to charge more. In the one case your parents could lose a lot down the road. In the other they just got stiffed for a little up front

In any event I'm more than willing to hang my so called peer out to dry simply because he either did the job wrong or he described his work wrong. A pro gets both right and can do so without confusing the customer. There’s simply no way around that conclusion.

[Shophound]

Irascible, well said.

I'd bet good money if I went out to his parent's unit I'd find it overcharged. I'd go double or nothing the system probably uses a piston metering device.

Overcharged piston regulated system.

Sounds like double trouble to me.

[Irascible]

Indeed. I'd bet good money and my own time. If he were local I'd go check it for free just to prove how right I am. Of course... if I were wrong you'd never hear about it. :D ;)

[dave and julie]

I haven't asked them how the system is working since the tech's visit, I'll be sure to do that soon.

I think it is a 4 ton in a 2750 sq ft. house with a finished walkout basement that adds another 1500 square feet. That thing has it's work cut out for it. Especially since it is a ranch house with the furnace at one end. The ductwork is nowhere near right, even with boosters in the ducts the furthest bedroom bakes in the summer and freezes in the winter. It's in a fairly affluent neighborhood too and recent construction. I've learned from you guys how critical installations are. When I was even younger and dumber than I am now, I just figured that was the best they could do. In reality the builder should have been made to fix the system.

It's probably half my dad's fault, he wanted the condenser out of sight and where it is I bet it reciculates 25% of the air that goes through it. It's in the coner of a courtyard in front of the house.

Anyway, I wish I could take you up on that bet, it would be interesting.

Oh yeah, it's got an eletronic air cleaner too! I knew you would like to know that.

I don't know if it is piston metered or not, I know mine is.

[Edited by dave and julie on 06-27-2005 at 04:09 PM]

[zzyzzx]

I got mine topped off a couple of weeks ago. It hadn't been serviced since it was installed in 1996. In a perfect world, it would not have leaked one bit, but I feel it was unrealistic for a unit to go that long without needing any (and it maybe needed one pound).

[chillbilly]

Leaked through the pores huh?
A serial blow and go'er.

[alexb]

In a perfect world, it would not have leaked one bit, but I feel it was unrealistic for a unit to go that long without needing [...]


Just tell me I'm full of it & I'll go away. --An engine in a car needs its oil changed, becuase the bits of crud & impurities are collected in the oil, and it needs to be changed from time to time. Isn't a compressor also a high-stress device that can produce such crud, that would be deposited in the oil? Would you laugh if I said I had someone out last year to evacuate & recharge my system because of this reason? I thought it must make the compressor run easier. Didn't see the guy put oil in though. How does this work..?

[Shophound]

Just tell me I'm full of it & I'll go away. --An engine in a car needs its oil changed, becuase the bits of crud & impurities are collected in the oil, and it needs to be changed from time to time. Isn't a compressor also a high-stress device that can produce such crud, that would be deposited in the oil? Would you laugh if I said I had someone out last year to evacuate & recharge my system because of this reason? I thought it must make the compressor run easier. Didn't see the guy put oil in though. How does this work..?


Main problem here is in your analogy. A car engine has internal combustion occuring while the engine is running. Some of these products of combustion blow by the piston rings and pollute the lubricating oil. This, more than any other factor, is why engine oil must be changed regularly. When I was on a Navy ship, it used lubricating oil in the main reduction gear, which was subject to heat and exposure to mechanical parts that would wear, but we used a lube oil purifier to continually reuse the same oil. Rumor had it some ships had their original furnishment of lube oil years after leaving the shipyards.

In an air conditioning system, the compressor lubricating oil operates in an extremely low moisture and atmospheric air environment. If the system is maintained, the compressor oil is never subjected to heat to the point where it might begin to break down and lose its lubricating abilities. It is true the oil may pick up bits of mechanical wear over time, but this is what filter/driers are for (as well as for continued moisture removal).
Any seasoned service technician can tell you that he's come across at least one old clunker system that's been churning away since the 1960's or earlier, complete with its original furnishment of oil, and even refrigerant charge. This indicates how a properly sealed, hermetic system can run an incredibly long time without an oil change.

As for your efforts at having your system evacuated and recharged with virgin refrigerant, you certainly didn't hurt anything if it was done correctly. Chances are that level of care didn't happen at installation, so you may be in better shape than before.
As your service technician I might have thought your request a bit unusual, but I was running around in a service truck before the internet came along, so I'm sure the customer base for many resi techs has changed considerably since my windshield time days.

[Irascible]

You're full of it Alex. :D

No... really. Shop gave the long explanation. I'll give the short. The tech that did the work should have looked befuddled at your request and should have tried to persuade you to not do it unless there was legitimate cause.

[Jultzya]

Originally posted by zzyzzx
I got mine topped off a couple of weeks ago. It hadn't been serviced since it was installed in 1996. In a perfect world, it would not have leaked one bit, but I feel it was unrealistic for a unit to go that long without needing any (and it maybe needed one pound).

I guess I need to schedule all my clients that have 10+ yr old equipment to schedule a 'top off' then! And check out their 'flux' capacitor for aliens while I'm at it too...

'maybe needed one pound'... I take this as the serviceman DIDN'T wiegh the refrigerant that he/she installed???? :eek:

BTW, I have several systems over 10 yrs that have not needed any refrigerant! Am I the only one doing something wrong here? :p

[Irascible]

You're doing something VERY wrong. You check flux capacitors for magnetic alignment, not alien infestation. Freakin' hackers. :rolleyes: