Massachusetts Zero flow through water side

Discussion in 'Maintenance and Troubleshooting' started by Gary Wilson, Dec 24, 2017.

  1. Gary Wilson

    Gary Wilson New Member

    I would typically call the tech support but hoping to get some idea what’s happening before life gets back to normal Tuesday.

    I installed a Waterfurnace NDV049 9 years ago. We had a flow meter that wasn’t working well some we removed it this week, while we were here doing other things unrelated to the geothermal.

    Homeowner emails and says unit is faulting out and he’s running his aux. I suspect my guys may have picked up some air when removing the flow meter.

    I go yesterday with my flush cart and no flow through the unit’s Hx. The homeowner had some hoses so out of sheer curiosity I hooked up street pressure; 60 psi and it’s just dripping out the other side, both directions.

    I have a hunch the unit stopped working before we got there.

    Thanks for any advice. Merry Christmas
  2. arkie6

    arkie6 Active Member Forum Leader

    Did the unit have any lockouts indicated prior to removing the flowmeter? What type of flowmeter? Is the removed flowmeter fully intact? Could part of the flowmeter have come free and traveled down the line creating a blockage?
  3. geoxne

    geoxne Active Member Forum Leader

    Check antifreeze concentration. If the unit was in a no flow condition because of air lock, it is possible to freeze the coax with marginal freeze protection. If it is frozen, you can quickly unfreeze it by running in cooling. Then correct antifreeze level.
  4. Gary Wilson

    Gary Wilson New Member

    I don’t know, I’m sure my guys weren’t looking for a code. I went yesterday (Saturday), didn’t call them asking questions. When I got there the lights were blinking on Water Flow and Low Pressure Comp.

    This is similar to what I installed in the initial install:
    Blue And White (F-451004LHN-24) 4.0 - 40 GPM Flow Meter; 1.5" FPT; IL-Blue & White

    The meter is still on site; I didn’t don’t pay much attention to it. I will check it out more thoroughly.
  5. Gary Wilson

    Gary Wilson New Member

    Thanks, I hadn’t thought of a freeze. This loop runs above freezing temps so that thought hadn’t crossed my mind. No antifreeze, just water. System runs in high 30s back to the field.

    One code was low pressure compressor; so that could be possible. Although the homeowner is an engineering professor (a nice guy!) and he did the hose trick during the week; he got no flow just like I got no flow. I thought he was mistaken when he emailed me saying he had a blocked Hx

    I could be a weird coincidence. The power is off to the unit at this point so it certainly will eliminate the freeze as a possibility.

    Possibly a cold loop and low of ref?
  6. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    Sounds like it froze solid.
  7. Gary Wilson

    Gary Wilson New Member

    Ok I’ll ask him to see if he can send Water through the coil with his hose setup. If yes I’ll go flush it and see what’s up with possible Low pressure on ref side Thanks for the help

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