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Weil McLain Gold GV Series 2 with Honeywell S9201a module - intermittent issues

MikeWeeks Member Posts: 3
Hi everyone,

I'm a relatively new homeowner with a 4 zone radiant heat setup, installed by a prior owner who was a steamfitter by trade. The system worked beautifully last winter, and now that we are starting to have cold weather in NJ this year we're noticing some intermittent issues.

We have a McLain Gold GV Series 2 boiler with a Honeywell s9201a control module, feeding into a Weil McLain Plus 40 water heater.

Over the last few weeks we've had issues with running out of hot water, and the last two days we've noticed the boiler not running normally. I've had PSEG (our local utility who provides HVAC servicing as well) out to look at the boiler and they are unable to determine what the issue is short of telling me to monitor, power cycle if the issue persists, and potentially replace the control module proactively to see if that's the issue.

In checking the boiler - we have done the following:

1. Monitored the light sequence on the control module to ensure it's not registering a fault: it is not

2. Checked and cleared out the venting pipes/tubes to ensure no obstructions: they're all clear

3. Checked the water levels, gas pressure and general mechanical health of the boiler: all looks good

Overall it runs perfectly fine - but periodically it is not able to prove the flame and goes into a repeat cycle followed by a lockout, which leaves us in the cold.

I'm open to suggestions on next steps - is there something I can do to further troubleshoot, or should I be looking for a local technician to come investigate?

Thanks in advance!


  • Tim McElwain
    Tim McElwain Member Posts: 4,506
    edited December 2011
    The control you have is

    a Honeywell S9301A Integrated Boiler Control which is no longer made. It can be replaced by a United Technologies 1013-200 if needed.

    Have you ohm tested the igniter?

    Did the gas company check microamps?

    What is the pressure differential across the pressure switch?

    The problem you are experiencing can be the result of the igniter not sensing flame and producing adequate microamps to always trigger the Integrated boiler control. The pressure switch affects operation sometimes when it does not completely make a manometer check should show 1.4" W.C. if lower than that check the following:

    1. Blockage in hoses

    2. Loose blower wheel on motor shaft

    3. blower motor not at proper RPM

    4. Blockage in air inlet or hose

    5. Blockage in flue pipe or termination

    6. Condensate trap filled with condensate.

    What was the inlet and outlet gas pressure?
  • icesailor
    icesailor Member Posts: 7,265
    GV Series 2:

    Those GV Series 2's seem to be a real bear. I have one in my customer base that has been going off for years. It gets worse with time. It goes off when you are standing there for no reason. The LP gas supplier services it. Your suggestions sound like it may be part of the problem but most everything on it has been replaced and the person who works on it is really on top of his game.

    In this case, I've felt that there are phasing/neutral problems because they are always blowing underground primary cables. I went to a house last summer, across the street that seemed to have lost their neutral when it was a problem with the transformer in the street. They had to put some sort of electrical back flow device on the transformer. There was voltage in the neutral and the two feeds weren't equal, then they became equal. I see it all the time.Everyone tells me that it doesn't matter. I think it does. But what the #[email protected]! do I know. I'm just a dumb plumber.
  • JStar
    JStar Member Posts: 2,752

    Where in NJ are you? I'd be happy to service your boiler if the problem persists.
  • Tim McElwain
    Tim McElwain Member Posts: 4,506
    One of the first things

    I teach in my classes is to determine correct polarity and power. Any voltage of any kind on the neutral leg will drive microprocessors crazy. The other thing is no ground or a poor or erratic ground when in doubt run a new ground from the pilot to the gas valve.
  • icesailor
    icesailor Member Posts: 7,265


    Where I work, the power was at one time, generated on the location with diesel generators. Now it comes by two large extension cords.

    There were four primary 3 phase circuits. A problem they had was keeping 3 phase circuits in balance. It was easy to let a phase become overloaded in relation to other phases in an area. Phases working together, become a neutral to each other. Isn't that why they have three light bulbs, one on each phase to see if one is using more power than the others?

    There was (and still is) a time when an area had a subdivision that only had one phase going into it and was fed from a branch of a three phase circuit. We plumbers started getting calls about people getting shocked when in the shower. Especially outside showers. The power company was at a loss as to the cause of the problem. They recommended that we put hoses on the handles to insulate the persons from the electricity trying to get to ground. I once measured 14 volts with a volt meter clamped to a screw driver stuck in the ground. This occurred for many years. I've gone into houses that had a failing neutral  or the other secondary leg not connecting completely. It isn't always easy to spot and if you believe some, it can't happen but it does. I've seen water get into an outside weather head and travel through capillary action, through the wire and drip down all over the neutral bar, making the connections lost. The guy called the shop in the AM to ask the boss why his dishwasher was shooing sparks from his dishwasher to his refrigerator. Water down the SE cable.

    If I see the lights dimming, I look for a problem. I just wonder when these unusual and hard to detect  drop outs, what relationship squirlly power has to do with it.
  • Plumdog_2
    Plumdog_2 Member Posts: 873
    Trouble with the Gold

    I found a Gold Series that ran for 12 years with polarity reversed! Then the board began buzzing and failed. The most common problem is the pressure switch not making GOOD contact. Sometimes the sequential light for the switch will be dim, or flicker when this occurs. Sometimes rust forms blockages inside the exhaust connector, which is tough to remove and clean. You have to poke, scrape and vacuum it out, and you can only get partway into it. But it makes a big difference in the pressure readings at the switch hoses.
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