reversed loop?

Discussion in 'Maintenance and Troubleshooting' started by ant, Feb 3, 2012.

  1. ant

    ant New Member

    Well the whole lot came to a deathly silence last night; the unit cuts off with the FP1 error everytime I restart now. I've given up. Luckily I booked a service call for Monday morning before it gave up the ghost. Of course, it's cold outside but I have great things to say about our gas fire insert. It is keeping the house from getting too cold. Yes, the JW3 jumper is cut - the installer cut it 2 years ago when we had these problems before. The compressor ran continuously for the rest of that year, but it warmed up shortly after that and we didnt realise that it continued to struggle. Ah so the DIP switch just runs the HWG pump. Well I'm impressed because the HSW was disabled and the pretank was definitely very hot at the top. The DIP switch was set to ON which according to the manual means that the HWG is disabled. Are there any important questions I should ask the HVAC guy when he comes on Monday?
     
  2. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    I'm starting to feel like a broken record...

    This may be another case where low refrigerant charge problem is being perceived as a water side problem.

    This can be consistent with high DSH temperature since low charge can cause very high compressor discharge superheat - unit could just about boil water in the little DSH exchanger if the DSH circ pump was not running.

    Depending on location and plumbing of buffer tank, thermosiphoning could move some hot water into the top of the tank - natural convection / no pump

    One brand of aftermarket DSH I've tested is designed to be mounted at the base of a water tank and works entirely without a pump (not well enough for me to buy them, though)
     
    Last edited: Feb 11, 2012
  3. ant

    ant New Member

    So the engineer came and found that there was mud in the ground loop and it needed to be flushed before any further work could be done on the system. As the system was still pressurised then I'm assuming that the mud was there from the beginning and the system hadn't been flushed properly. This explains a lack of water flow. Any idea of what damage has been done to the system?
     
  4. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    perhaps a little abbrasive wear to some parts, but it is likely ok if it flushes.
     
  5. Calladrilling

    Calladrilling Member Industry Professional Forum Leader

    You should be okay.
    Mud is not to harsh.. Sand is a lot more damaging than mud would be. Purge the hell out of it in both directions. Maybe your original contractor didn't have a strong enough purge cart to flush the mud out?
     
  6. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    Has that cleared the errors?
     
  7. ant

    ant New Member


    Of course I'm caught between the original installer and the well driller. The well driller says that he'll be here either tomorrow or Thursday and flush the system. Hopefully this is the cause of everything.


    I shall report back once everything is flushed and started again.
     
  8. ant

    ant New Member

    The well drillers came and flushed the ground loop. It was perfectly clean. The HVAC engineer had given up when he found water with sediment come out oft he centre of the ground loop motors. I turns out the water had been sitting there for 3 years and there was a little corrosion collecting there. This was not the problem. Sigh. The well drillers were champions.

    So the HVAC bloke came back and and found the real cause. The prize goes to broken record Curt - the refrigerant was low. The tech refilled and the system works better than I every remember. The test will come tomorrow when the temperature drops below freezing but so far the system is producing lots of hot air.

    So the next question is where did the refrigerant go. He put in some dye so we can see if and where it is leaking in 2 weeks.
     
  9. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Leaks

    Leaks in the refrigeration side of any system can be tough to find, I've spent 30 years looking for leaks. I took me 15 years to learn that leaks can be intermittent. The first place I now look for a slight or intermittent leak is the service ports for the refrigerant system. The little Schrader pins, (think tire air valve) can fail to fully seal.

    The act of attaching charging hoses to a system can re-seat the seal, so the leak is never found. If the seals on the pins are damaged there is a tool to replace them without removing the refrigerant charge. I have also had brand new out of the box systems where the pins are not tightly sealed from the manufacturer.

    All that said I did have a fifteen year old unit in Connecticut leaking R-22 into the loops.

    Good luck.

    Mark
     
  10. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    Glad to have guessed correctly.

    Beware dyes - Some compressor manufacturers are quite adamant that nothing other than refrigerant and oil be in their units. I've heard some will void compressor warranty if dye is used.

    HVAC bloke should return with a sniffer and some soapy bubbles and find the leak that way. Starts around the service ports and brazed joints.

    Request proof of factory authorization to use dye.
     
    Last edited: Feb 18, 2012
  11. ant

    ant New Member

    Thanks for all the advice. :)

    Now when I look at my temperature charts I see the the EWT is higher than the LWT and the world is sane again. So why should low refrigerant cause the temps to reverse in the ground loop. Could it be that the compressor is working so hard to extract heat inefficiently it is actually heating up the ground water?
     
  12. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    I don't get the angle you are coming from...What charts? The EWT is supposed to be higher in heating mode!
     
  13. ant

    ant New Member

    I've taken temperature readings from the outside of the ground loop pipes. Now that the system is working (in heating mode), I see that the EWT is indeed higher than the LWT.

    When the system was low on refrigerant, the system didnt produce very much heat and the EWT was actually lower than the LWT. I was curious if any one could tell me why this might be so. Could the compressor be heating the LWT when the refrigerant is low?
     
  14. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Not happening.I would check instruments and temp readings.
     
  15. ACES-Energy

    ACES-Energy Member Industry Professional Forum Leader

    Post photos of where you are taking measurements on the unit..maybe the unit is incorrectly labeled?
     

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