# Weil McLain Gold trouble shooting



## jimdad07 (Mar 15, 2010)

I was on call this past weekend and got a call for a boiler that was down. I arrived on site and found that it was a Weil McLain Gold series boiler. The boiler would prove airflow, start the hot surface ignitor, open the gas valve and fire. Almost as soon as it fired, it would go out with no error code on the boiler control module. There is no flame rod in the system, it proves ignition through the hot surface ignitor. The only thing it would do was turn the flame indicator led off when it lit. I went through every thing that I could think of and could find nothing wrong. Went through the Weil McLain trouble shooting guide and they said what I was thinking, bad control module. The unit starts the draft motor, proves airflow, puts power to the ignitor, ignites and quits. Went back today with the new control module and had the same problem, $#!%. The only difference in the new control module and the old one, is one more indicator light for the ignition sequence: Proven Airflow. This model boiler has a dual pressure switch which has a port for positive airflow and one for negative. What was happening was that the pressure switch was not holding even though the combustion fan was still running and still making pressure (tested with manometer). Replaced the pressure switch and the unit took right off and stayed running. The moral of the story is watch yourself when trouble shooting the older Honeywell boiler control modules that are on the Gold boilers, even the Weil McLain book didn't say anything about that switch doing what it did.


----------



## mtfallsmikey (Mar 16, 2010)

Had a little problem on my own furnace yesterday, has a Beckett AFG burner, R7184 primary...forgot how to bring it out of lockout...gone are the days when a couple of jumpers would make anyting work!...I'd be kind of lost on the newer controls, been out of the biz for a few years....good call, rep for ye.


----------



## mtfallsmikey (Mar 16, 2010)

catfish1 said:


> Ever have trouble with the gas regulators? I've got the odd call for a boiler that starts briefly, and then shuts down right away. Turns out if the gas regulator is to close, the boiler sucks the pipe empty of gas (between the boiler and reg) before the reg can respond, shutting down the boiler. Natural gas is fairly new here, so that had several of us stumped for a bit.




Is it a 1/2, or 2 psi natural gas system? Not much in the way of regulator problems with natural, some with LP,


----------



## jimdad07 (Mar 16, 2010)

catfish1 said:


> Ever have trouble with the gas regulators? I've got the odd call for a boiler that starts briefly, and then shuts down right away. Turns out if the gas regulator is to close, the boiler sucks the pipe empty of gas (between the boiler and reg) before the reg can respond, shutting down the boiler. Natural gas is fairly new here, so that had several of us stumped for a bit.[/QUOTE
> 
> I have seen that a few times on LP, but not on natural gas. I have had many times when an installer set the gas pressure wrong and the gas valve would not even open, or there is a negative pressure gas valve on the unit and some one tries to set the manifold pressure to positive pressure. Good luck with natural gas, you will find it much cleaner to work on.


----------



## mtfallsmikey (Mar 17, 2010)

catfish1 said:


> I _think_ it was 1/2 (I've not seen too many higher pressure regs here) It was a tandem boiler set up, with one reg doing both boilers. I did not think that was correct, and was causing some of the trouble also. There is still a bit of a learning curve with natural gas up here.




In my locality, 2 psi natural is the norm now. also, I would imagine pipe sizing could play a role too...


----------



## tmschuller (Mar 17, 2010)

my 2 cents worth... had similar problems on that boiler.. but it turned out that a spider had built a web in vent tube that came off the gas valve... not letting it work right... Its things like that that make you want to put a new one in. I have had some really strange things with the lochnivar boilers that we have here on the campus... we just put in a couple of the camus (spelled?) and are smaller look like good units.. anyone here work on those?


----------



## mtfallsmikey (Mar 17, 2010)

tmschuller said:


> my 2 cents worth... had similar problems on that boiler.. but it turned out that a spider had built a web in vent tube that came off the gas valve... not letting it work right... Its things like that that make you want to put a new one in. I have had some really strange things with the lochnivar boilers that we have here on the campus... we just put in a couple of the camus (spelled?) and are smaller look like good units.. anyone here work on those?



Only older ones.....are they condensing boilers? At my old job, a new building was going up when I left, were going to install 2 large Lochinvars to preheat the fresh air....I believe they were each 1 mil. BTU.


----------



## Joe Antonio (Mar 10, 2017)

tmschuller is right. if you have this problem (airflow switch) the boiler try to start when power switch is turned on but shuts down. Jump the thermostat wires, if boiler starts open the jump, check that the two rubber/plastic hoses are not disconnected, if everything looks right could be what tmschuller said, "spider had built a web". What I did was; disconnected the hoses blow them end put them back. Worked like a charm.
Good luck.


----------

