Prestige Triangle Tube Low Water Pressure

Discussion in 'Boiler Forum' started by TD Willis, Jan 3, 2019.

  1. TD Willis

    TD Willis New Member

    Joined:
    Jan 3, 2019
    Location:
    Alaska
    Hello,

    I'm looking for opinions here. I am not a plumber. I'm reaching out to the forums here because I don't have a lot of plumber options where I live in Alaska.

    I have a Prestige Triangle Tube system. It provides heat for radiant floor heating (2 zones) and DHW.

    We had an issue where the pressure was dropping below 10 psi which would shut the boiler down. We replaced the regulator and back flow so pressure now sits at 20 psi. Problem now is that whenever there is any drop in psi, the system reverts back to a low pressure error.

    What we see is that the DHW will cycle through and as soon as it reaches the set point/temp, the water pressure drops a bit and the system goes back to the low water pressure error. The water pressure tends to drop from 20 psi to 15 psi. Also, when the DHW is first turned back on, the water pressure jumps from 25 to 30 psi.

    Heat works fine as long as the DHW is shut off. However, if DHW is on, system cuts off due to low water before it returns to CH.

    However, on extremely cold days (i.e. single digits or below 0), the water pressure in CH mode will gradually drop from 20 psi to 15 psi over the course of 30 to 40 hours and then rise back up to 20 psi over the course of about 3 hours. Temps in the house never drop more than a degree or two below set point.

    Anyone have any idea what might be going on.

    Edited for typo.
     
  2. Dana

    Dana In the trades

    Joined:
    Jan 14, 2009
    Location:
    01609
    Most boilers on 1-2 story houses work fine at 13 psi. It's not unusual for the boiler to stop spit out an error at 10psi. Have you downloaded and read the manual on your exact model? (There have been several series from Triangle Tube using the term "Prestige", and they're not all identical.)

    Without more information on the model and system it's hard to make good suggestions.

    If your expansion tank is properly charged for the target system pressure and is sized properly for the water volume most radiant floor systems won't see that large a swing in pressure. AT 30psi the pressure relief valve might start spitting something.

    Zone valves or pumps turning on/off will cause spikes in pressure ( both high and low spikes) which could be what's tripping the sensor. With a properly charged expansion tank the tank behaves a bit like a shock absorber, damping out the pressure spikes.
     
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  4. TD Willis

    TD Willis New Member

    Joined:
    Jan 3, 2019
    Location:
    Alaska
    Thanks for the input.

    Our system specifically is a Prestige 110 Excellence
     
  5. Dana

    Dana In the trades

    Joined:
    Jan 14, 2009
    Location:
    01609
    Is this the right manual?
     

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