New York Advice on blowing out desuperheater lines for shut-down

Discussion in 'Maintenance and Troubleshooting' started by libby, Nov 12, 2014.

  1. libby

    libby New Member


    I'm trying to shut down the heat pump system when away and not sure why blowing out desuperheater lines with a compressor is not completely successful. Since there are lots of loops (creating "traps") in the lines running inside the heat pump, not all the water is coming out probably because it is hard to push water up a pipe.

    Will a bigger compressor work (if so what size), or is there another strategy that can work?


  2. ACES-Energy

    ACES-Energy Member Industry Professional Forum Leader

    Why are you draining the desuperheater loop? Are you going away for winter and shutting down the system?

    Are you completely isolating the internal desuperheater loop from the hot water tanks and house (to be sure nothing is coming back from the storage tanks for house lines)?

    We use the propress version of this valve to isolate the de-super loop. This allows us to easily drain if necessary, but more importantly to a cleansing back-wash/flush/clean as needed.

    Attached Files:

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  3. bill41

    bill41 New Member

    Thanks for your reply.

    The draining is for shutting down for long periods, but not all winter. Just for about 3 weeks at a time. Previously I drained the entire water line system by gravity with no issues. With the addition of the desuperheater the fun begins.

    As I see isolation of tank, it is for a better performance from the compressor. Since lines are first emptied in the rest of the house, there is no pressure exerted on the water lines of the desuperheater. Your idea of using the valve from the URL should work on the hot water heater side and perhaps then a compressor to finish the job on the other. The drain of the valve assists in this providing a second exit for water.

    I have also unscrewed the pin on the small pump to release any water there. I was wondering if a small compressor would do (at present it doesn't with h/w tank not isolated) or a bigger compressor is better to provide sustainable pressure.

    Appreciate the advice very much.
  4. libby

    libby New Member

    But the most important point for us is to be able to blow out the desuperheater lines within the heat pump where there are a lot of pockets for water to collect in small "traps". Without sustained pressure from a compressor I fear water will be left. I just don't know how big a compressor I have to go to make sure everything is cleared out. My small oil-less compressor with a small 1 gallon tank does not seem to do the trick.

    Any help would be appreciated. Thanks
  5. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    air should be adequate, are you letting the house freeze?
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  6. libby

    libby New Member

    Yes the house will freeze. However the room with the heat pump and h/w tank never freezes except if I accidentally close the door to the mechanical room. But with an expensive heat pump I just don't want to take the chance and leave any water in the lines just in case.

    This is all new to me so I appreciate the help.
  7. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    It is getting to the time of year to winterize my travel trailer. I drain the fresh water. Then I blow out the pipes with air then I blow in the pink non-toxic RV antifreeze. You could do the same to the de-super-heater coils.

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  8. geoxne

    geoxne Active Member Forum Leader

    DSHHX.JPG Most DSH "coils" are not really a coil. See pic. Have a look inside the box and see if it will drain by gravity. If not, with those nice tball isolation/drain valves you could pump in PG very easily.

    Please remember to disable your DSH pump if you drain it.
    libby likes this.
  9. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Nice illustration.
  10. libby

    libby New Member

    Good idea. Odd that non-toxic is a bit hard to find where I am only one outlet does when not sold out.
  11. libby

    libby New Member

    Thanks. I'll check. The lines are hidden behind insulation but I should be able to peel back and check. Screw on pump already pulled in case water trapped.
  12. libby

    libby New Member

    Thanks to everyone here. This is really helping.

  13. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Check the RV dealers. The auto parts store around Cleveland carry it.
    libby likes this.
  14. libby

    libby New Member

    Thanks Mark.

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