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CGA weil mclain

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loadii
loadii Member Posts: 6
in Gas Heating

got a new boiler installed recently and today it threw a fault false flame. the installer came a notice there is water on the plug. the plug on the upper left and it leaks to the safety switch on the lower left. What do you call this plug? This was installed in the summer. Is it fixable?

leak.jpg

Comments

  • Bernie_the_Brewer
    Bernie_the_Brewer Member Posts: 24

    Was the installer who came out the same one who installed the boiler this summer? What did he think?

    Trying to keep Bernie burning!

  • HVACNUT
    HVACNUT Member Posts: 7,326

    The 4 pin plug with the 2 reds, a yellow, and a white is the Water Temperature/LWCO sensor.

    And it leaked to the bottom left? The Rollout Switch with the yellow wires?

    Once the Rollout blows, its done. It needs to be replaced.

    As far as the sensor, I wouldn’t assume that's where the leak generated. I'd look at the 3/4" tap in the block on top of the boiler, behind the supply pipe. There should either be an air eliminator there, or it should be capped. Something is leaking from up high and trailing down between the block and the jacket.

    I would start by shutting off the power. Fix the leak. Disconnect everything from the board, and dry everything well. Use a hair dryer if you want. Disconnect the sensor and dry the area and the connector. If the Rollout is still good, plug everything back in. Turn OFF the gas. Turn on the power. Raise the thermostat and see what the board does. If it goes through the whole trial for ignition sequence (without actual ignition, of course), then try with the gas on. ONCE!

    WM would have the resistance specs on the sensor if needed.

  • loadii
    loadii Member Posts: 6

    The guy who installed the unit came out last night and tighten the temperature sensor and it worked whole day today. This evening it through the error again. I reset the boiler and it came back online.

    it looks like there is moisture around the teflone tape around the temperature senor.

    behind the supply pipe, it has an air eliminator.

    Will have them air eliminator.

  • loadii
    loadii Member Posts: 6

    I turned the heat off and i can see water sipping out from teflone tape around the LWCO plugin.

  • 109A_5
    109A_5 Member Posts: 3,723

    If it is that sensor is leaking at the threads and not something up higher, at some point you probably will have to drain (or partially drain) the system, remove the sensor, inspect the treads (sensor and block), and if all looks good put it back in with tape and dope. This should be done before it turns into a corroded mess.

    image.png

    The other thing is the "false flame" error means there is a flame when there should not be and the sensor leak may have nothing to do with that.

    image.png

    https://www.weil-mclain.com/wp-content/uploads/CGa-Series-4-Boiler-Manual-0425.pdf

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    ScottSecor
  • loadii
    loadii Member Posts: 6

    this is helpful. what could be the cause of the false fire and how to debug it. i can reset the fault and it will do a cycle and then the error is triggered.

    also noticed there are 4 wires coming out from the guard dog low water device but only 2 wires are connected. it is connected to the transformer. where should the other 2 wires be connected to. please share any diagrams if you have it.

    many tganks

  • HVACNUT
    HVACNUT Member Posts: 7,326

    Its pretty rare that a factory installed fitting is leaking. Could be, but rare. Start looking higher.

  • loadii
    loadii Member Posts: 6
    edited February 3

    yes have the contractor coming out again. As the boiler already have a LWCO, is a separate guard dog still necessary. I don't believe that device is completely connected because there are 2 wires that aren't connected to anything.

    From the manual for the boiler, looks like I can connect to the p4 limits. There is auto-reset and manual-reset. What is the recommended approach for the guard dog?

    Regarding fittings from factory, It make sense that it shouldn't have any issues. Was watching a video on youtube of Mikey Pipes, he was assembling the same unit and the nipple on the supply line was not proper secured and didn't have proper dope on it. I guess it could happen.

  • loadii
    loadii Member Posts: 6

    contractor came and re-apply dope on the LWCO sensor. so far it is ok and don't see any water.

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