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CGA weil mclain

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loadii
loadii Member Posts: 34
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
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Comments

  • Bernie_the_Brewer
    Bernie_the_Brewer Member Posts: 33

    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: 7,410

    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.

    tcassano87
  • loadii
    loadii Member Posts: 34

    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: 34

    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: 3,885

    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: 34

    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: 7,410

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

  • loadii
    loadii Member Posts: 34
    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: 34

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

  • loadii
    loadii Member Posts: 34
    edited February 4

    don’t sessions any more water leak but it threw the same error again. where is the flame sensor located for the cga 5.

  • HVACNUT
    HVACNUT Member Posts: 7,410
    https://forum.heatinghelp.com/discussion/comment/1886140#Comment_1886140

    Down in the burner compartment attached to the pilot assembly.

    The boiler is new, so unless its been burning terribly, I wouldn’t think that's the issue. What code is being displayed?

  • tcassano87
    tcassano87 Member Posts: 134
    edited February 4

    According to what someone posted, the flame error is saying flame when there shouldn’t be. I haven’t worked on the series 4 yet but to me that means something isn’t closing the gas valve after the boiler is supposed to to shut down. Allowing the pilot or flame to stay lit. Have you tried cleaning the pilot assembly and checking it looks ok?The Temp/LWCO probe may have just been a separate issue happening at the same time

  • loadii
    loadii Member Posts: 34

    The LCD turned red and it said fault false flame. I don’t recall seeing any code. Is the code on the lcd panel?

  • 109A_5
    109A_5 Member Posts: 3,885
    image.png image.png image.png
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    tcassano87
  • loadii
    loadii Member Posts: 34

    thank you for the picture. super helpful. If the wiring is in question, would it cause intermittent faults? What is the most likely cause when it is intermittent?

    It would work for several hours with multiple cycles and then it would stop working. A reset will make it work again and the cycle repeats.

  • 109A_5
    109A_5 Member Posts: 3,885

    I'd inspect the wiring for abrasions, being crushed or pinched and secure connections. I'd also inspect the insulation on the sensor probe for contamination or damage (the area of blueish shading in the image below), clean or replace if needed.

    If you have the proper test equipment (a multimeter or equivalent capable of DC microAmps) Flame Rectification current could be measured also.

    All assuming the flame goes out when actually expected every time, if a gas valve (main or pilot) is sticking open you may have to catch it in the act.

    image.png
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    GGross
  • michaelb0315
    michaelb0315 Member Posts: 13

    Unfortunately, the CGAs are having issues with the left cast-iron sections leaking. On cold fires, water leaks directly on to the roll-out. We were forced to change five of them out under warranty. All within a year old.

    HVACNUT
  • loadii
    loadii Member Posts: 34

    In my case, the leaking was from the LWCO and it was clearly visible. When it is under warranty, does it cover the contractor cost?

  • loadii
    loadii Member Posts: 34

    What is the fault code when the rollout is tripped? Would it also indicate false flame?

  • HVACNUT
    HVACNUT Member Posts: 7,410
    https://forum.heatinghelp.com/discussion/comment/1886281#Comment_1886281

    No. My WM Pro Tools app doesn't have the CGa Series 4 listed yet, but the CGi uses the same Unity-CI control board.

    Screenshot_20260204_180155_Drive.jpg

    You can turn off the power and remove the plate that the Rollout is attached to and set it aside so you can see if the pilot flame goes out when it's supposed to. When you turn the power back on to check, be careful to set the plate so the Rollout isn't touching anything but air. If it shorts out, its done. They used to give you a spare Rollout. You also should have the manual.

  • loadii
    loadii Member Posts: 34

    thanks for sharing. i also remember seeing manual limit, is that another fault? need to pay close attention if it happens again.

  • 109A_5
    109A_5 Member Posts: 3,885

    The Rollout thermal switch is actually a Thermal fuse. When tripped it would have to be replaced (Red Circle).

    These wires and aluminum tube (Yellow arrows) go down to the Pilot / Flame Sensor assembly.

    image.png
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • loadii
    loadii Member Posts: 34

    I called tech support and they were pretty helpful. Because the boiler is new, they said the most likely cause is the gas pressure. Will need to hire a person who was trained by Weil Mclain to do some diagnostic.

  • loadii
    loadii Member Posts: 34

    tech recommends checking the gas pressure. I live in NYC and we use gas from Con Edison. How does one check that pressure?

  • 109A_5
    109A_5 Member Posts: 3,885

    A Tech should easily able to test the Gas pressure with a Manometer. And it should be verified if not to just rule it out.

    The thing is, the way I see it, the way gas valves are designed so the inlet pressure would actually help the valve close not keep it open. To me the only way the pressure would keep it open is if the pressure is so high it can actually open (or keep the valve open) against the solenoid's spring pressure. Maybe the internal regulator is bad, but still the incoming gas pressure should not be that high.

    And if the pressure was that high the burner may have other combustion issues.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • HVACNUT
    HVACNUT Member Posts: 7,410

    @loadii , if you have the installation manual, all the answers about how to check gas pressures are in there. I don't know how NYC regulates static pressure, but WM wants no more than 13" wc static. They list pipe sizing charts and everything. Check it out.

  • loadii
    loadii Member Posts: 34
    edited February 6

    It has been a few days since the last trip. it seems to be related to the leak from the LWCO. Also don't see any water around the LWCO with the fix.

    tcassano87
  • tim smith
    tim smith Member Posts: 2,928

    Gas pressure should not be throwing false flame signal. When does it happen? Early morning, mid day or evening? once a day? Many times? Suspecting may condensation dripping down during cold start maybe. Just sleuthing a bit.

  • loadii
    loadii Member Posts: 34

    It started last Saturday. contractor came and noticed there was water around the thread of the LWCO sensor. contractor tighten the sensor but then it tripped again but it didn't stopped the leak. contractor finally took the sensor out and apply dope and put it back in. immediately the next morning in tripped again but didn't see any visible water by the sensor. I reset the boiler, and since the reset, it has not trip again.

    When it had the leak, I can see water dripping on to the burner tubes. Also I can feel the water on the insulation behind where the circuit board was mounted.

    I hope that was the reason it tripped the false flame. Many thanks for everyone's wonderful suggestions.

    tcassano87HVACNUT
  • HVACNUT
    HVACNUT Member Posts: 7,410

    Just keep doing what you're doing. Keep an eye on it.

    I wonder if there are more boilers that shipped with loose sensors. Sealant issue? Bad tap in the block? Or is this singular?

  • loadii
    loadii Member Posts: 34

    the good news is that I haven't seen a fault for more than a week now. however noticed a weird situation as if the boiler threw a fault but eventually reset itself and came back online. I keep the temp at around 63 at night, when the temp goes below it fires up the boiler, noticed from 3-5AM last night, the temp dropped down to 61 as if the boiler wasn't running. Also just now, the boiler is running however the temp in the boiler drop down to 100.

    What is the behavior when the boiler can't ignite? According to the documentation, it'll try multiple times and with some exponential backoff.

  • loadii
    loadii Member Posts: 34

    does the cga series 3 have a temperature differential lockout?

  • 109A_5
    109A_5 Member Posts: 3,885
    image.png

    With that controller is it a Series 3 or Series 4 ?

    image.png image.png
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • loadii
    loadii Member Posts: 34
    IMG_3271.jpeg

    i believe it is a series 3.

    ScottSecor
  • 109A_5
    109A_5 Member Posts: 3,885

    Looks like a Series 4 to me. Curious, why do you think it is a Series 3 ?

    image.png

    The only two temperature sensors I saw in the diagram were in the LWCO sensor assembly. I believe they are for a sanity check, although I could not find an error message if one has an implausible reading or the differential is too wide.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • loadii
    loadii Member Posts: 34

    you are 100%, i missed read that as serial number.

    again it threw the false flame and the red panel blinked 5 times.

  • HVACNUT
    HVACNUT Member Posts: 7,410
    https://forum.heatinghelp.com/discussion/comment/1887217#Comment_1887217

    That control is new to me. I thought WM was going with a universal U-Control to use throughout their line of boilers. And like I mentioned earlier, the Series 4 isn't even listed on the WM app yet. And it was updated 12-25. I can find your boiler with a CP# search, but I can't bring up any manuals on it.

  • 109A_5
    109A_5 Member Posts: 3,885
    edited February 10

    @HVACNUT Here is the manual I posted earlier in this thread.

    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
  • 109A_5
    109A_5 Member Posts: 3,885
    https://forum.heatinghelp.com/discussion/comment/1887217#Comment_1887217

    As far as the 'False Flame' error, is the boiler still under warranty ? If not the things mentioned previously in the thread should be checked, some of which may need some diagnostic equipment.

    For some reason the controller apparently thinks there is a flame present when their should not be. The actual presents of the flame may or may not be true.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • loadii
    loadii Member Posts: 34

    The boiler was installed Oct 2025. It should be under warranty, I hope. I got a contractor in the weil maclain site to come and diagnose the problem.

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