R-410A heat pump compressors 'de-coupling' during heat operation

[thermojohn]

Hi - Been a while since I posted here.

I am an HVAC contractor and am noticing a pattern with several R-410A compressors in (less than one year old) heat pump systems we've installed. After a cold night, I'll get a call from someone saying their outside unit is noisey and system is not heating.

What I see when I arrive is the compressor is running, but not pumping as pressures are equalized. Somehow the motor has 'de-coupled' from the mechanical assembly internally. It is not the same internal relief sound normally heard in R-22 based compressors.

Turning off the compressor for a day gives it time to cool down (or catch up with itself), then it operates normally again.

Anyone else experienced this? What causes this? Reversing valve sticking in mid-position? Long defrost cycle resulting in high head pressure?

BTW, these are Goodman units with Copeland scrolls. So far, have only seen this with 2.5 ton units.

[SBKold]

probably sticking rev valve

[seanddd]

There's a Goodman recall on this, that might be it.

[thermojohn]

There's a Goodman recall on this, that might be it.

Really? What kind of recall?

[seanddd]

SR-036 and SR-041. You can search for old discussion
threads in this forum.


Really? What kind of recall?

[tlb]

had same kind of problems RV's been sticking.goodman did have recall on "Danun" valves I think i got name right they are junk.had one just month ago screwed on gauges with compressor running pressures were equal and compressor sounded rough. got to checking and the valve was stuck

[VTP99]

[QUOTE=thermojohn;9151851] Somehow the motor has 'de-coupled' from the mechanical assembly internally. Copeland scrolls.

I don't think that is possible and then work again.

[thermojohn]

OK - Now we're getting somewhere. Danged ol' Chinese reversing valves. Looks like the imprint of a flower embossed on the valve. Don't know the brand.

Thank you for responding everyone. Anyone else have any problems with these?

[just_opinion]

OK - Now we're getting somewhere. Danged ol' Chinese reversing valves. Looks like the imprint of a flower embossed on the valve. Don't know the brand.

Thank you for responding everyone. Anyone else have any problems with these?

Before we are all shooting down those chinese this chinese that R-valve, read EVERY word on the side of the compressor. The answer is there. Too many compressor and R-valve have been changed for no reason. Except it does not speak the native tongue. :D

Sorry, I cannot give further information. I have to treat you as DYI.

[thermojohn]

I don't think that is possible and then work again.

I hear ya. I've experienced this twice, though. Sounds like only the motor is running (like a sheared shaft). It might have been operating through the 'stuck in mid position' valve, but usually I'll hear the whooshing sound of gas going through the valve if it is stuck in mid position. That was not happening the times I've experienced this. Give the compressor time to cool, and restart it and it operates like nothing ever happened.

I do not know how the shaft is connected to the motor internally. I was thinking like a magnetic drive to protect the compressor from high pressure or something. Only seen this with R-410 compressor and not R-22 types.

I'm all ears if you know something about this.

[seanddd]

internal relief?


I hear ya. I've experienced this twice, though. Sounds like only the motor is running (like a sheared shaft). It might have been operating through the 'stuck in mid position' valve, but usually I'll hear the whooshing sound of gas going through the valve if it is stuck in mid position. That was not happening the times I've experienced this. Give the compressor time to cool, and restart it and it operates like nothing ever happened.

I do not know how the shaft is connected to the motor internally. I was thinking like a magnetic drive to protect the compressor from high pressure or something. Only seen this with R-410 compressor and not R-22 types.

I'm all ears if you know something about this.

[thermojohn]

Before we are all shooting down those chinese this chinese that R-valve, read EVERY word on the side of the compressor. The answer is there. Too many compressor and R-valve have been changed for no reason. Except it does not speak the native tongue. :D

Sorry, I cannot give further information. I have to treat you as DYI.

I am a licensed contractor and not DIY. Do I need to post in the pro section to get the real scoop? It has been a long time since I've posted here at HVAC Talk. A lot of changes have taken place here since.

[BaldLoonie]

You've got the post count for sure, so apply for pro membership and it gives you access to the educational forum as well.

[thermojohn]

OK, will do. Again, thanks for the input everyone on this.

[Kevin O'Neill]

Lennox has had the same problem. Copeland 1.5 and 2 ton scrolls on R410a. They have switched to another compressor manufacturer for their small scrolls.

[VTP99]

.

[VTP99]

Lennox has had the same problem. Copeland 1.5 and 2 ton scrolls on R410a. They have switched to another compressor manufacturer for their small scrolls.

What is the problem with the compressors ?

[SBKold]

I wanna know too.

What is reading the side of compressor going to do?

We are not talking big scrolls here with that ASTS thing.

[thermojohn]

Lennox has had the same problem. Copeland 1.5 and 2 ton scrolls on R410a. They have switched to another compressor manufacturer for their small scrolls.

Interesting.... Here's something else I found out today regarding this unit:

The original compressor in this unit is a ZP25K5E-PFV-130
The replacement compressor for warranty is a ZP26K3E-PFV-930

I wonder what the difference is in the make-up internally? Other than 1,000 BTU nominal increase in capacity?

So is it the compressor or reversing valve? I'm not a parts changer until I verify the failure of the component. This situation I have not seen 'fail before my eyes' yet.

[Kevin O'Neill]

The compressors get noisy and stop pumping. Only happens in heat mode and below 30 degrees outside. Turning it off and waiting a few hours sometimes fixes it....for a while.

Jumping the defrost board for soft changeover helps sometimes as well.

Permanent cure, replace with another brand of compressor.

[tlb]

from the units i have had that had similar symptoms as this usually RV. acts like compressor is bad but is not. but if unit is run for extended period of time with RV bypassing could cause compressor damage check and see if this particular unit has the RV with a recall on it

[SBKold]

The compressors get noisy and stop pumping. Only happens in heat mode and below 30 degrees outside. Turning it off and waiting a few hours sometimes fixes it....for a while.

Jumping the defrost board for soft changeover helps sometimes as well.

Permanent cure, replace with another brand of compressor.

WHATTTT?????

Lets talk more about this in the PRO section.

[thermojohn]

[QUOTE=Kevin O'Neill;9156611]The compressors get noisy and stop pumping. Only happens in heat mode and below 30 degrees outside. Turning it off and waiting a few hours sometimes fixes it....for a while.
QUOTE]

Right on to what I've experienced. So we have liquid floodback during low load. That eats up reversing valves, and compressors. Since the compressor is downstream of the accumulator, and the RV is not, which one is the real culprit?

[Kevin O'Neill]

That is what Lennox thought at first.

Replacing the reversing valve does not help.

It IS the copeland scroll compressor, but only on the 1.5 and 2 ton sizes.

Maybe on the Goodman, it is something else.

[thermojohn]

WHATTTT?????

Lets talk more about this in the PRO section.

Wait for me........ I'm not allowed in there yet. Still gotta get my info to the admin.

[Kevin O'Neill]

Lennox just shipped us a new outdoor unit to fix that problem for a customer. 1.5 ton outdoor unit, r410a.

[bzzline]

why could it not be the txv on the outdoor coil

[Kevin O'Neill]

It could be a lot of things. I tested for that.

There is no pressure differential between the suction and discharge ports on the compressor. The compressor discharge pipe does not even get warm. The compressor amps are very low.

With a bad TXV, there would be a pressure difference.

With a bad reversing valve there would be a small pressure difference even if it was stuck in the middle. Plus the discharge pipe would get warm if not hot if the compressor was pumping at all because the motor heat would go into the discharge gas. A thermal imaging camera did not show any temperature difference between the suction and discharge lines.

To me, that is a bad compressor that is not pumping.

After extensive testing on other systems, that is what Lennox decided too.

They don't use that compressor any more and are not having any more problems of that type that I have heard of.

[thermojohn]

Good idea using the thermal imaging camera to diagnose this problem. Do you have a model # of the compressor handy?

Seems to be a pattern using compressors sized 1/2 ton lower than the capacity of the equipment. So in the 2.5 ton units I've been dealing with, a ZP25 compressor is used. (25,000 nominal BTU's)

[bzzline]

would be nice if goodman had a compressor discharge port for testing about time for a two stage txv on small ton heatpump condenser units

[just_opinion]

Like I said on first page, Let's read all info on the compressor itself before we go to next step.

Remember - Scroll will STOP pumping if it is hot. If this feature is within the compressor, then it does its job.

[Kevin O'Neill]

Like I said on first page, Let's read all info on the compressor itself before we go to next step.

Remember - Scroll will STOP pumping if it is hot. If this feature is within the compressor, then it does its job.

Internal overload will take any compressor that has one off line. Is there something about a scroll that it will run and not pump when hot? Where did you find this information? I have never heard of it.

[VTP99]

Is there something about a scroll that it will run and not pump when hot?

High pressure bypass internally.

[thermojohn]

IDK either. Maybe the low voltage temperature limit switch that Copeland used on their earlier generation scroll heads. None of those problems are happening here, though.

Update.... Since I haven't seen the reversing valve operate incorrectly, and verified it was switching properly today, I'm not going to replace it... Yet. I can't see replacing one unless it is a verified failed component.

There is a recommendation to install an RV switching delay kit which apparently solves the RV problem. Anyone have any input on that?

[Kevin O'Neill]

High pressure bypass internally.

The pressure differential was zero. The internal relief will not trip when the pressure differential between high side and low side is zero.'

Lennox says the scrolls seperate.

[VTP99]

The pressure differential was zero. The internal relief will not trip when the pressure differential between high side and low side is zero.'

Lennox says the scrolls seperate.

What if it trips prematurely. :toetap:

[just_opinion]

Internal overload will take any compressor that has one off line. Is there something about a scroll that it will run and not pump when hot? Where did you find this information? I have never heard of it.

I think Copleland designed this type of scroll 5 years back. Seen them in a lot of Lennox R-22 and R410A.

You often see them now in many Copeland scroll commpressor in the commercial unit.

Like I said, this sucker will stop pumping if the pressure get too low. AND every tech freaks out and say "IT IS BAD COMPRESSOR WITH BAD DISC"

[BobEPS]

Before we are all shooting down those chinese this chinese that R-valve, read EVERY word on the side of the compressor. The answer is there. Too many compressor and R-valve have been changed for no reason. Except it does not speak the native tongue. :D

Sorry, I cannot give further information. I have to treat you as DYI.
What does the compressor have to do with the reversing valve being stuck.
I had a SSZ14 2 months ago same symptoms after recovering the ref. the reversing valve (Un stuck and allowed some more ref to escape). by the way it was a 2.5 ton.

[SBKold]

What does the compressor have to do with the reversing valve being stuck.
I had a SSZ14 2 months ago same symptoms after recovering the ref. the reversing valve (Un stuck and allowed some more ref to escape). by the way it was a 2.5 ton.

So what did you do? Did you put a valve on it? Or replace the unit

[Crazy4thenucks]

It sounds like the scrolls are seperating (cant remember the exact term) due to liquid floodback to the compressor...scrolls cant pump liquid...If this problem persists you will smash the srolls into peices and it will not pump ever again. Find out why your flooding back before you start replacing the compressor and have the same issue with the next one....one clue may be the low ambient conditions at night.

[lions_lair]

Not trying to be argumentative..but one of the main features of a copeland scroll..is..it WILL pump liquid. We had a run on bad indoor txv's this past summer. Flooding liquid back..to the point that the whole compressor was sweating. No heat on discharge line,zero to negative super heat. Recip compressors..they can not pump liquid. Just sayin. :):munching:

[Crazy4thenucks]

Not trying to be argumentative..but one of the main features of a copeland scroll..is..it WILL pump liquid. We had a run on bad indoor txv's this past summer. Flooding liquid back..to the point that the whole compressor was sweating. No heat on discharge line,zero to negative super heat. Recip compressors..they can not pump liquid. Just sayin. :):munching:


You are correct.............to a point. Scrolls are more TOLERANT to liquid pumping...they will no survive for long doing it, but will last longer than a recip. Have you ever seen the inside of a scroll after liquid gets to it and destroys the scrolls, not cool.

[BobEPS]

So what did you do? Did you put a valve on it? Or replace the unit
Considering I had changed the indoor coil a month earlier after discovering a leak...In the middle of the !@@#$^&* coil . Customer was "Freaking furious" and insisted I replace the OD unit!
Customer described a intermittent problem of OD unit running constantly,Pre dating the coil leak.Told customer to not shut off the unit when problem occurred and call right away.Out tons of labor on this one plus dryers @ 410!
Adding insult to injury had another AEPF3137 leak a month later on a unit installed around the same time as that one. Rust in a few rows of aluminum fin rows?
Some kind of electrolytic action?

[lions_lair]

No I can't say I have seen that. Maybe I will google it or try to find it on youtube. Have u seen it..I mean seen a compressor disassembled to see what it looks like? If so could u describe it. I really can't get a mental picture of it in my head. In fact I don't ever recall having a scroll come up(locked rotor). Which I would think it would if the scrolls were desroyed. I've had lightning hit them,bad caps burn them up,a bad internal overload,a contactor weld in(causing a burn out). I've installed hundreds of them and had only a hand full of failures. Never once said..wow I don't know why this one is a burn out..ALWAYS another part failed, or act of nature was the cause of the failure. At least that has been my experience.

[BobbyBJr]

I am familiar with the problem that Kevin mentions with the Copeland compressors. We had to change out 6 or 7 outdoor units last winter because of it, but I thought it only affected the 2 step compressors that unload. Last winter it was all Lennox stuff we saw it in, but this winter we've had two Rheem units with the same problem. Lennox is using Interlink compressors in some of their stuff to avoid the problem. Rheem is still scratching their head over the two we have intermittently doing it.

[SJProwler]

That is what Lennox thought at first.

Replacing the reversing valve does not help.

It IS the copeland scroll compressor, but only on the 1.5 and 2 ton sizes.

Maybe on the Goodman, it is something else.

Kevin,

If there is an alert out from Davenet on this can you e-mail me the number or info on it so I can share it with my Dealer.

My XP21 (2 ton installed in Dec.) will not heat since this past weekend when it was in cool mode for a few hours.

Compressor is very loud (which is strange for the XP21) and get absolutely no heat. Will sit and run like this forever until the indoor temp drops enough to bring on the furnace. I have it on Emer Heat now and sent an e-mail to my dealer.

[wormy]

Copeland's Advanced Scroll Temp Protection
(http://www.emersonclimate.com/en-US/products/compressors/scroll_compressors/copeland_scroll_commercial/Pages/advanced_scroll_temperature_protection.aspx)
For those wanting to know more about
one of Copeland's ways to protect their compressors
(commercial compressors though.... don't think its on
the residential yet.... just posted this since its similiar)

[Crazy4thenucks]

Emerson will be releasing Core Sense technology standard on all scrolls...not sure when this will happen, but it should help with some of these issues peopke are experiencing with the scrolls....

[Kevin O'Neill]

Kevin,

If there is an alert out from Davenet on this can you e-mail me the number or info on it so I can share it with my Dealer.

My XP21 (2 ton installed in Dec.) will not heat since this past weekend when it was in cool mode for a few hours.

Compressor is very loud (which is strange for the XP21) and get absolutely no heat. Will sit and run like this forever until the indoor temp drops enough to bring on the furnace. I have it on Emer Heat now and sent an e-mail to my dealer.

I have been dealing with my tech rep. I do not have a bulletin on it. I will see what I can find out. I have not yet seen the problem on any 2 stage scrolls, but I understand they have it too.

[SJProwler]

I have been dealing with my tech rep. I do not have a bulletin on it. I will see what I can find out. I have not yet seen the problem on any 2 stage scrolls, but I understand they have it too.

Thank You VERY much for the bulletin you sent. My tech just left. Reversing valve sticking, both switching in to cool and switching back to heat. As soon as he tapped lightly with the handle of his hammer it would switch.

New Valve will be ordered first thing Monday along with a few spares since they installed several units just like mine around the same time frame.

The tech was VERY appreciative that I had the bulletin when he arrived.

I'm in emergency heat until the new one gets here but since my backup is SLP-98 it's no biggie. I feel bad for those with resistance backup heat though.

Thanks again!

Glenn :cheers:

[SJProwler]

Old Thread with an update,

My Dealer just replaced my 2nd reversing valve Saturday. After being in cool mode all summer and working fine, the first time the XP-21 went in to heat mode it had the same symptoms, Loud, no heat.

After my tech had a long conversation with Lennox over the issue it was discovered the original replacement reversing valve sent by lennox was defective and had the same part number as the original. The reversing valve has now been replaced a 2nd time with a different part number and manufacturer. So far no issues but it's only been a day.