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crown bwc 90 gas boiler

samber
samber Member Posts: 5
in Gas Heating
looking for help with the above boiler that's a little over 10 years old. start sequence seems fine, boiler will start and run till water temp reaches 115 to 120 degrees then shuts down, after post purge it repeats. no error codes. it's a direct vent unit and there's combustion smoke coming out so I don't think there's an obstruction. the inducer motor failed about 5 years ago and I replaced it. could the pressure switch be failing after running a few minutes and causing a shut down? any help would be appreciated.

Comments

  • HomerJSmith
    HomerJSmith Member Posts: 2,635
    Any B or E fault codes? Not enough information to make a comment. It could be a lot of things. Give us a description of the installation a pic of the display at shutdown, etc.

  • samber
    samber Member Posts: 5
    edited February 2023
    no fault codes. just goes into standby mode. sequence is call for heat code, check pressure, pre purge, ignition, runs a few minutes and turns ignition off, post purge, never reaches set point of 160 degrees, acts as though it reached hi limit, standby mode.
    no error codes no soft or hard lockout. it then starts the cycle over again.
    waiting for a new pressure switch to arrive, wondering if it could be something else.
  • delta T
    delta T Member Posts: 884
    edited February 2023
    I'm skeptical that its the pressure switch, I would expect that to throw a fault code. I'd be checking the demand circuit if it were me, maybe a failing zone valve end switch, or maybe a wonky thermostat heat anticipator? (depends on what kind of system you have). Hard to diagnose without a multi meter and being able to see the screen when it shuts off. Any chance of taking a video? Is this an intermittent random failure, or is it consistent every time? How long is it off before it re-cycles and runs again?
  • samber
    samber Member Posts: 5
    the system has 3 zone valve and 3 very basic tstats, they are currently all in the manual open position. the display shows the following: 1stanby prepurge, 2 ignition, 3 call for heat, after about 1 minute of running, 1 post purge, brief 7 call for heat ended then 0 standby, 5 check pressure, after about 1 minute starts over and does this constantly.
    one thing I've noticed is when doing a prepurge the inducer motor seems to be having trouble starting it starts and stops 5 or 6 times before it stays running. maybe in the inducer motor going bad again?
    I do hear a click from the pressure switch when the inducer motor stops.
    last time the inducer motor went bad it did throw a fault code for fan not running.
    don't know how to test inducer motor

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