Air to air heat pump problem

Mark Eatherton1

Wallies, I got a request for help in an area I have little to no experience in and thought I'd throw this out for comments by some of the more refrigerant oriented wallies. Here's his problem...

BEGIN LETTER

I spoke with you on the phone this morning concerning a major problem I am having with a heat pump installation.

I built a 3800 ft2 living area home utilizing two Janitrol heat pumps totaling 5.5 tons. In the sale of the home 14 months ago there was a condition that stated we would eliminate a noticeable/shrill system noise.

To-date my HVAC company and I have failed to find any solution that has even moderated the noise.

We have taken the following steps, all of which have failed:

1) Sound blankets on both compressors
2) Replaced both compressors
3) Installed in-line bellows in the lines leading from the compressors into the wall
4) The two lines from the compressors to the air handlers in the attic pass through a 2x4 wall; during construction these were constrained in the walls to avoid potential vibration sounds. We have torn out the wall, removed the constraints and re-sheet rocked the wall -- all to no avail
5) Installed hard rubber sleeves around the outside lines from the compressor to the entry wall, then torqued them in-place

We have been unable to solve this problem that is likely to lead to litigation of some sort by the buyers.

Please help solve this mystery if you have any similar experiences that have yielded
to ideas you've tried out in their resolution.

Best regard,
Stan

END OF LETTER

My initial though would be a defective expansion valve, but that should cause other problems too. What think ye Wallies?

TIA

ME

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Ranger

Mark,Is the shrill ....

...right after shut-down or when the machine is running?Are both the machines having the same problem?What type of compressors are in the unit(s),Scroll or Recip?

Dale

Muffler

Many heat pumps as well as larger AC's have a muffler on the hot gas discharge that looks like a filter dryer, about the same shape. There is a baffle in the muffler that can come loose and make a heck of a noise, I would try a c clamp on the muffler tighten slightly and see if the noise changes, safety equip. is a must here a well as someone quick on the disconnect.

Randy Berg_2

Check and see if the line size of the piping is correct for the lenght of run. York ran into this problem several years ago and incresed the liq. line from 5/16 to 3/8. Just a thought, also has anyone contacted Janitrol about the problem? Keep us updated.

Matt Undy

I'll preface this with sayign i'm not all that familiar with refigeration but could the installer have failed to ream the tubing when they were making up the refigerant lines, possibly along with a perticualarly dull cutting wheel? If its on both units it is less likely to be a failure but a problem with component selection or installation procedures(of course a acomonent that always fails wouldn't surprise me either). Did the system always make this noise or did it crop up at some point? Was its onset gradual or sudden? Does using a screwdriver or similar object as a stethecope allow you to pinpont where it is coming from? Is the TXV matched to the system? Is the indoor/outdoor unit pairing recommended by the manufacturer? If a TXV was used, was any factory installed metering device removed?

Those are a lot of questions but the question about onset, if it was sudden or slow, did both or jsut one do it first, did it always do it, will make about half those drop out.

These are just some observations of things installation manuals emphisise that installers who don't seem to bother reading them miss.

Matt

Jeff Lawrence_24

I'm gonna go with Ranger

We need more information.

My first thought was a gross overcharge and the internal overload screaming.



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David_5

Heatpumps

I'm not sure what the problem is but we know what is isn't.
1 It is not internal to the compresso because of sound blankets.
2 Both compressors have been replaced and both units make the noise. Further rules out compressor.
3 I don't know what inline belows are. Maybe vibration eliminators. If so it didn't help. It also doesn't sound like a problem with the line sets. These systems may not have expansion valves. The may have fixed orifices. How do the systems run, ok? I have heard scroll compressors cause a pulsing noise that was transmitted through the lines into the house. Does the sound happen in heat and cool or just one. If only cooling, maybe a liquid line restriction. I hope my ramble helps.

David

jim lockard

wild thought

What size Machines ?? Are the serial numbers close to each other (same run)? Have you installed a sight glass in the Liquid Line? Bubbles?? what is your liquid line temp and pressure. vapor temp and pressure? have you checked internal piping of machines to make sure crossovers at Condenser coil are correct along with other in machine piping?? The TXV can be checked with gages, sight glass, removing the bulb and placing in warm water, even frosting of the coil at the distruber. ?? what would happen if you installed another heat pump on the system ?? Details , Details. J.Lockard

jim lockard

muffler

do not think janitrol has one on 2.5 and 3.0 machines. as for compressors they were using Bristol at the time(Copeland) Now

Floyd_5

Mark....

it's the reversing valve......the suckers not seating completely and a little bit of refrigerant is squeaking by, creating the shrill squeal....

Bet ya a beer or drink of your choice next time I see ya!!!!

Floyd

JimGPE_10

I'm liking this one.

The reversing valves squeel like crazy when the compressor shuts down and they switch over, equallizing the pressure. Some leakage through might just make this happen.

Suggest a sharp tap while the machine is running might be a good diagnostic tool. If an "impact adjustment" either eliminates the sound completely for a bit or changes it in some way, this could be your way home.

Also if this is it, I would think it would quiet down in the heating mode. Does it?

By the way, does the unit "work"? Does the home stay cool when the unit is running? If so, it probably isn't problems with the charge.

Lastly, pull open the casing and see if perhaps one of Chuck's wood chucks is living inside and howling when the unit runs....

Tony_8

Something I've seen

Quite a bit, is the compressor mounting bolts are too tight and the rubbers can't absorb the vibration. Seems to only happen on scrolls. Blankets, etc. don't help in this case either. Floyd's reversing valve idea sounds logical if it only does it in one mode but not the opposite.

I hope we find out the cause when it's discovered !

MikeB34

is the sound

located at the indoor or outdoor units? have they looked at the air movement equipment? the condenser fan motor or blower mtoe/bearings?

if you disconnect the power to the various components in the system, will the sound stop?

What has been lloked at. So far I see everyone looking at the refrigerant system, and not the entire system.

I would look at the fans and remove them from the sequence of operation. if the sound stops that is the component in Q.

If it is in the refrigeration system. I would check tubing/reaming. or the 4 way valve. Little else would cause the noise.

Good luck.

Mike

Mark Eatherton1

So many questions...

So little time. I'm going to make direct contact with the questioner and have him respond directly tio everyones questions. Thans for all your input. Even I'm learning something here:-)

ME

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Dale

Reversing valve

Reading the other posts got me thinking ( dangerous) reversing valves on residential systems are normally in the heating side. If the voltage to the coil was too low perhaps it's only partially shifting for cooling. I would check the voltage on the reversing coil when the unit is running.

Ken D.

Heat Pump

Mark, Where is the noise most pronounced? Is it indoors or outdoors? Take a screwdriver and touch it to the liquid, hot vapor and cold vapor lines. Put your ear to the screwdriver and see if you can narrow it down as to which component is the origin. You can use a stethoscope instead. Disconnect the indoor fan to eliminate that as a possiblity. Do likewise to the outdoor fan and compressor to narrow your search. If it is a scroll compressor, the discharge check valve can be the culprit. Make sure the service valves are open all the way. How old is the unit? Has this been happening a long time or just start? As you say, so many questions and so little time. Check and record the pressures, superheat and subcooling along with amperage draw of the various components. Let me know.

jim lockard

Rev. Valve

You would think with a brand new unit when the rev. valve slamed home in heating, if it was a valve noise that would cure it Wonder what happens when the rev valve is disconnected during the cooling cycle ??? is the noise gone ? has the system been evacuated to below 800 microns?
Copper chip in valve ?? on two machines?? J.Lockard

jim lockard

compressor bolts

Mark said that the compressors have been changed. you would think that over tight bolts would have been picked up on.

don_42

All

great replies,and boy it sure sounds like chasing one tail
with all the replacement compressor.

First thing one would need to do is to make sure its a match system.Then the next step would be look at the line set for proper size and distance from ah to hp.
Then one would need to look at the distribution system,very
important..overlook and not design properly by most which
create more problem then just noise.

Are we sure we are not just hearing gurgling noise thru the
lineset from it not being charge properly?

"System charge and performace evaluation we must take temperature across the entire system before we can effectively evaluate any part of the system."

As Dan would say you've got to get out of the boiler room.
Same holds true here,and a vapor compression system is less forgiving then a boiler system.

joel_19

hmm

Replaced the compressors? that's achore on most HP's I'd probably change the whole condensor before I did that. if they have a fixed orifice they can really scream if it's not the right size. Even if it's correct it still can be a problem can you add a hp style TXV??? Are the line sizes correct for the velocity??? Is it constant or onlu on shutdown?? Need some more info.

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jim lockard

TXV

ME suggested that the TXV maybe defective. I am not so sure that Janitrol's small air handlers have TXV's. What in the flow check circuit would cause the noise??
Wrong size piston? Rev Valve ? outdoor flow check ? compressor? If you close the service valves and pump N2 thru the system do you get noise ? liquid to suction/ suction to liquid? just pressure no change of liquid to vapor I know?? Looking for answers. J.Lockard

Mark Eatherton

Wallies...

The builder has read these threads and printed them and is asking his HVAC contractor for some answers. Thanks for your input, and hang loose.

ME