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  1. #1

    Sluggish reversing valve

    To give a little history, this is a Goodman 5 ton heat pump 15 or 16 seer, can't remember which. Installed 4 years ago and have not had one heating season without problems. One year in service and the compression goes out and had to be replaced along with thx valve. 6 month later reversing valve gets stuck in cooling. Valve taken out and replaced with whole dryer assemble, only thing left was the compressor. 8 weeks later new reversing valve gets stuck in between heat and cooling mode. Added Zerol Ice to help free valve. With a little work of banging and switching the valve from heat and cooling many times, the valve does switch but sluggishly. It will take about 5 minutes once the compressor turns on to fully switch into heating and the same with cooling. For that 5 minutes, the compressor is a little noisey and little to no refrigerant is moving. I have had a local Goodman installer do the repairs from day one but I think maybe the proper procedures where not followed. What should I expect from the tech that replaces it again. I read that there should be a Nitrogen purge placed on the unit during brazing. I know for a fact that was not done for the compressor nor the reversing valve. Should a sweep of the system be done with R22 before another reversing valve is put back in? Any help would be appreciated.

  2. #2
    Join Date
    Dec 2004
    Location
    maple ridge, bc
    Posts
    107
    Cut your losses now friend. This heat pump was not installed properly initially (sloppy work) and you should expect more expensive repairs every year you keep this loser.
    Do the math then replace with a quality machine. Forget the nitrogen business, that isn't causing your problems.

  3. #3
    deerwhistler, That very thought is on my mind. Oh for the rest of you I did forget to say that it is a R410 system. If not the nitrogen business, could it be caused by the first compressor going bad that could have contaminated the system. I just hate for things to defeat me and I hate even more tossing money at a problem only to have it bite me in the end..

  4. #4
    Join Date
    Dec 2004
    Location
    maple ridge, bc
    Posts
    107
    I've been in the business for 30 years and have seen this too many times. There are very definite install procedures and the good a/c mechanics know this and faithfully follow them, always. When corners are cut, like not evacuating the new system properly, you get what you got. This isn't your fault but next install ask the installer lots of questions and make sure his company knows that you are paying attention. To keep you off their back they are more likely to send out a qualified mechanic.
    Good luck.

  5. #5
    I know that I have been told not to beat a dead horse but today a new reversing valve which included everything except the compressor was put in. System was flushed and recharged only to find that the same thing was happening. Now the real question. Has anyone ever come across a Copeland scroll compressor that would work at times and not at other times? By not working I mean there is no difference in pressure from the low to high side. After 5 or ten minutes you can hear the compressor chatter in an oscillating way as it become louder, then nice smooth very quite operation. This can happen in the heat mode or cooling but in the cooling I have noticed no cooling down of the suction line. It may run for a couple of days then as if the reversing valve is stuck in between or the compressor is not compressing to cause the valve not to work happens again. I have another compressor on the way with both the inside and out THX's on the way. What has perplexed the Tech is that it works sometimes. This will be the second compressor in 1.5 years and the 3rd reversing valve.

    Second question, could the outside THX failed causing the compressor to fail making it look like the rv has failed? At this point I am in for one more compressor refit, any more problems deerwhistle I cut my losses this spring.

  6. #6
    Join Date
    Dec 2004
    Location
    maple ridge, bc
    Posts
    107
    Actually, this sounds like an over charge of refrigerant, that may well be the culprit. I have never seen a scroll compressor fail the way you've described. The scroll is a constant volume machine and can take a lot of abuse. There are no valves in the comp.
    Too much refrigerant will cause a warm suction line, meaning no appreciable cooling.

    I'd like you to start up the hp and with a bare hand (be very cautious here) touch the liquid line, it should be close to your body temp. Next do the same for the suction line and if possible use whatever thermometer you have. This will be used to check the system superheat. It's here where I need to know the operating system pressures.
    Do this before the tech shows up as all your problems are likely the result of too much
    refrigerant. When the comp was changed last time, very likely the tech simply removed the R22 and placed it in a separate bottle. After the parts are in he probably just re-installed the old R22 (and an overcharge). Your tech should absolutely have checked for the sub-cooling and the superheat.
    Good luck be careful

  7. #7
    The Tech replaced the refrigerant (which is 410) by weight according to the manufactor's specs as a starter. At start up, the guages show extreme low pressure differences to no pressure changes from suction to liquid, just as if there has been a disengagement between scroll and motor (broken shaft). When this is happening there is no movement of refrigerant and the pressure on the guages is mostly at static. This could go on for 5 to 10 minutes and at times much longer, then for what ever reason, refrigerant begins to move and delta is achieved between suction and liquid until this happens there is no temp difference between the two thus no superheat or sub cooling. I can tell if it is going to engage by sound that I have described above. Oh, another sign is that when the system in on if you pull the electrical disconnect and then engage it again you would expect a hard startup because of refrigerant back pressure but there is no resistance and motor starts up easily. This is being done mostly in heating mode. In cooling or defrost we get the same results except if left to run long enough in cooling the liquid line is a little colder then the suction line which is the reverse of what is suppose to be. I have mentioned this to techs, they say because it is so cold outside that the refrigerant is not behaving as it should as during summer operation.

    Sorry to be so long winded but wanted to give as much info as I can.

  8. #8
    Join Date
    Dec 2004
    Location
    maple ridge, bc
    Posts
    107
    Has anyone mentioned wiring in a 'hard start kit'? All that is is capacitor and current relay.
    On start up, if the comp is seizing and won't spin, the hard start zaps the windings with approx 6X the normal starting current. Cost about $$$ and installs simply by piggy-backing on to the run capacitor. There are only 2 wires involved and this is definitely worth the low cost.
    In winter low ambient conditions it is possible the liquid line could get cool to the touch, this is why low ambient switches are sometimes used. In cooling mode with low ambient the outdoor coil is run either 'on/off' or modulating type. Neither is expensive but if the hi-side pressure is tapped through a schrader valve you need to hire a journeyman.
    good luck
    Last edited by jpsmith1cm; 01-07-2012 at 12:14 PM. Reason: Removed Pricing

  9. #9
    At no time is the compressor seizing, it is free wheeling.

  10. #10
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,397
    How did you make that determination?



    Assuming that is true, then the RV is the logical cause, BUT determining why is another thing altogether

  11. #11
    You can hear the compressor motor running but no difference in pressure and the revesing valve has been replaced 2 times in the last 8 weeks to solve what was thought to be a sticking valve.

  12. #12
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,397
    I can't conceive of a situation where the compressor would run but not pump, then start pumping properly at some point later.

    Where are the pressures being taken?

  13. #13
    Quote Originally Posted by jpsmith1cm View Post
    I can't conceive of a situation where the compressor would run but not pump, then start pumping properly at some point later.

    Where are the pressures being taken?
    LOL there in is why we are preplexed. That is the reason that the rv was replaced first because we could not think of a reason for the comp to act the way that it does, that did not point to the Rv but after two installs of rv it's hard to believe that you can get 2 bad ones in a row. That is why we are looking at the comp. The pressure is being taken at the shrader valves using the service ports. I noticed on youtube that a fellow had the top cut off and showed unless the top seal forces the scroll down there was little compression. The fellow said that as the compressor starts up the lack of compression allows for a earier startup with less amp draw but as a little presssure builds on top of the seal forcing it down and thus putting more pressure on the scroll then the pressure builds quickly. What do I know, sounded good to me.

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