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Thread: This is odd

  1. #14
    Join Date
    Feb 2002
    Posts
    525
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    If both systems were in heating mode and water flow light came on, this means that temperature of water/refrigerant hx has reached less than 15 deg for closed loop or 30 deg for open loop. Could be low water flow from loop side or on an older WF unit low on refrigerant from leaky air coil. If units were in cooling mode, low water flow would normally be indicated by a high pressure fault light (loss of outside fan motor or dirty condenser coil on and air-air system).

  2. #15
    Join Date
    Sep 2007
    Location
    State College, PA
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    2,970
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    Thread Starter
    So I added less than a pint of water to the one system and all was good.

    On the second one, I added a few oz. of R-22 and all was good. I checked for leak, but could not find one. Pressure was a little low.

    Watched it run with no issues for over an hour. Next day, customer cales and low pressure fault again.

    This is 2 stage with dual pumps for the well. It seems at one point during diagnosis that only one of the pumps was running, But at other times they were both running and at others times none were running.

    Any thoughts, ideas, suggestions?
    Can someone please explain to me -
    Why is there never enough time to do it right the first time, but plenty of time to do it twice?


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  3. #16
    Join Date
    Nov 2001
    Location
    Seattle, WA
    Posts
    8,103
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    Sometime, and just sometimes if these systems use pressure switches to indicate water flow the calcium or other material can plug up the line to the pressure switch, typically 1/4", and cause a fault even though nothing is wrong with the unit. Remove the line to the pressure switch to see if there is any build up. Most any swimming pool place has those switches if you can't find them anywhere else. I have a few machines that do this about every two years. I just put new switches on and clean out the taps.
    "The American Republic will endure until the day Congress discovers it can bribe the public with the public's own money.
    - Alexis de Toqueville, 1835

  4. #17
    Join Date
    Feb 2002
    Posts
    525
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    WaterFurnace geo hp's don't use water pressure switches, they use thermistors to sense line temperatures. With this being a two-stage hp, is it the old Bristol TS compressor, or a Copeland two-stage scroll? The TS system did use staged flow center pumps for systems 4 tons and up. The Copeland scrolls bring both pumps on for stage one. If the units are the Primer E models (with the TS compressors) and have had a scroll replacement kit installed, be sure to check the pumps wiring at the control board and at both pumps. I was assisting an area Tech following up such a compressor replacement job. The original installer's electrictian had run a three wire BX cable from the unit to the pumps, using black and white wires for stage 1 and stage 2 pumps and the green wire for common on one side of the 240 wiring (and not to NEC!). The tech wired the control board end as one would--green to equipment ground and white and black for 240. At the pumps end, this put the two pumps in series and caused one pump to overheat. It got so hot that it melted the GL fitting on top of the flow center, as well as the o-rings on the three-way-valve. We found this after replacing the defective pump and trying to pressure up the loops. Ended up having to replace the flow center itself.

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