Problem with Weil-Mclain boiler

CamR

My WM boiler is acting up. Have had no heat for the last 2 days. I have it shut off for now. When I turn it on, the power light comes on, then the TSTAT/Circ light, and then that's it. I'm thinking the control module is bad because no lights flash to tell me there's any kind of error or bad sensor, and the flame light doesn't flash after the allotted 15 seconds to detect flame from the pilot. BUT - could the electric pilot ignitor be bad? It's a CG model, and control module is 11365-605

Tom_133

CamR,

Dont just swap that control (though it could be the problem), make sure your igniter works, and your air switch is working. You can ohm out your igniter for continuity and check voltage on the air switch. Then if those both pass, you can think about the board.

Steamhead

What model series W-M CG? Does the ignitor light up as the control goes thru the trial for ignition?

Tim McElwain

Do you perhaps have a picture of the Integrated Boiler Control? It will help me to look up the troubleshooting for that control.

CamR

Steam head, the ignitor doesn't light up. After the boiler is turned on, about 5 seconds later the circulator kicks on, and then from there nothing else happens to it. Tim, the control module is a UT 11365-605

CamR

Here's the module

CamR

It was working, working, working, then it just wasn't. No failure lights, no smoke or gas smell, the heat just stopped.

Steamhead

@Tim McElwain will confirm this, but I believe on most of those units the igniter runs on 120 volts. If there is voltage at the igniter plug but it doesn't light up, the igniter is bad.

Tim McElwain

Does this unit have a Spark Ignited Pilot or is it a Hot Surface Igniter? Which version of CG is it an "a" (CGa) version?

CamR

I believe Spark ignited, but I'm not sure. The gas flows into this metal thing with a knob you can turn off or on, then down to the tubes on the bottom of the boiler. Yes it's a CGa Gold

CamR

Here's the inside

JUGHNE

Can you post a good shot of the wiring diagram, it may be on the back side of the doors.

Tim McElwain

From the picture of the boiler it is a spark ignited pilot system. When you call for heat do you here it sparking at all? Do you have a multi meter? If so at the Honeywell gas valve see if you have 24 volts to PV to PV/MV. If no spark and no 24 to the gas valve do you have 120 volt power to the United Technology integrated Control 1135-605? If so is there 24 volts coming from the Integrated Control. If not then replace that control.

CamR

When it calls for heat there is no spark at all

CamR

Unfortunately do not have a voltmeter, have purchased the pilot ignitor/thermocouple (comes as an assembly, will replace those, also bought the control module. I will replace the PI/TC assembly first, see if that fixes it. If not, then I'll assume it's a bad control module and will replace the module

Tim McElwain

Really not the way to properly troubleshoot and diagnose you may be throwing away money. I would suggest you spend some and hire a professional to take a look at your system. By the way your system does not have a thermocouple so you may have the wrong assembly. What are the numbers on the pilot it is usually stamped in the metal?

CamR

Well it has this steel tube that comes off the gas valve and goes under the burner tubes and goes next to the pilot ignitor, guess maybe it's not a thermocouple, but not sure then what it is

CamR

This is what I'm talking about

CamR

That matches what's on my system

HVACNUT

Yes that's the spark ignitor and flame sensor.
If the existing assembly and wires look clean and intact. All molex connectors fully seated. Good ground.
But like you said, there were no dummy lights at all, for flame loss or any other code.

JUGHNE

Before the module will spark, it must see that there are no open limits and that the vent damper is open. Any one of these simple devices could keep the ignitor from sparking and pilot gas flowing.
Your wiring diagram would show us what limits there are....some might even be resettable with the push of a button.

Tim McElwain

Here is the diagram for this boiler -https://www.weil-mclain.com/sites/default/files/field-file/CGa Series 2 Boiler Manual 1016 Web Version - Starting CP7540456.pdf

Tim McElwain

The diagram will not do you much good unless you have a meter so otherwise we are just guessing.

JUGHNE

After you cir pump turns does your vent damper open?
That must happen before firing.
You can read the sequence in the manual that Tim has posted above.
One of the limits has a small red reset button.

If you are not sure of any of this happening you can change your parts, maybe work or not.
Then call a pro for help.

CamR

Sorry, Jughne, nothing on my system has a reset button. At least not one I can see anywhere. Vent damper does not open. Lighting sequence suggests it has to have power, then turn on circulator/get call for heat from thermostat, then limit light has to come on, then damper opens, then flame. Also, I just noticed my Vent damper has been in the "hold open" position at least since we moved in just over a year ago. Boiler was installed 10-10-2013

CamR

Here's the wiring diagram. And nevermind, found that reset button

CamR

Finally got boiler to work, after hitting that reset, heard an odd noise, then got flashing flame light. Now we're making progress!

CamR

Haha so that weird noise was because I forgot to reopen the gas valve. Opened the valve, turned boiler on and it's working! Do I still need to replace anything?

HVACNUT

Well, that button you pushed was to reset the spill switch.
If it happens again you'll need a pro to go over the whole system including the chimney.
The spill switch is a safety device that basically prevents the boiler from firing if it reaches the spill switch max temperature.
The flue gases are not escaping out the chimney, but coming back through the draft hood. That means carbon monoxide.
I could have been a downdraft or other obscure situation but to repeat, if it happens again, it must be checked. It could be a life threatening situation.
Do you have a low level carbon monoxide detector?
The damper can be left open but you'll lose a few % in efficiency.

JUGHNE

That could be why the vent damper was in the lock open position. The chimney draft could be marginal. By leaving the damper open there is some draft established by the basement warm air flowing upward.

You should have a good CO detector or 2 near the boiler.

You might be able to return the new parts if they are still sealed as they come off the shelf.

You should download and print the manual.
This will give you some idea of future issues.

arod1521

Im having the same problem with a cgi4 series 3...New help the flame will come up for a few seconds then I can hear a click flame turns off n then it starts the cycle again.

HVACNUT

Do the burners each ignite, or just the pilot?
Could be the flame sensor in the pilot burner assembly needs to be cleaned. Using a dollar bill works. You don't want to scratch it. So don't use four quarters.
Also check all grounds for tightness.

arod1521

They do ignite for a few seconds then turns off making it start the cycle again.

HVACNUT

So try what I said and post back.