Weil McLain gas boiler, possibly bad gas valve?

[Pete C]

Got up this morning to no hot water.

Went down to the basement and found the boiler cycling through its start up routine. Blower on, igniter fires, visible pilot flame, 24v to gas valve. solenoid clicks, but no gas to burner.

I tried smacking the to see if it would open, but no luck.

Went upstairs, called the service company and was told the tech would be out in a few hours.

About a half hour later, I went back down to make sure I had remembered to turn off the boiler so it wouldn't keep trying to start.
When I got down there, the boiler had successfully started and was already up to operating temp.

Seems to me that the valve eventually unstuck itself.

My GF said she was gonna have the service guy check it regardless. Not a bad idea.

The tech came after I left for work. He cleaned draft inducer and hoses. Replaced highvents.

I talked to him over the phone and he said the blower was not creating enough of a draft.

If this is the case, why was I getting voltage to the gas valve? It seems to me that it wouldn't energize the gas valve until all conditions were met.

I this not so?

Im not questioning the stuff he did, but I suspect I still have a valve that is questionable.

 

[Fitter30]

Brand and complete model of gas valve?

 

[Sponsor]

 

[Pete C]

Can't see a model number anywhere. It is a honeywell valve. I'll see if I can attach a pic

Boiler is a Weil McLain CGi-4-PIN, series 2, 100k btu.

There is a Weil McLain indirect water heater connected. Multiple zones, 3, I think. Nest thermostats.

 

[Pete C]

 

[Fitter30]

Do you have the manual that came with the boiler. It may contain a parts list.

 

[Pete C]

Do you have the manual that came with the boiler. It may contain a parts list.

Don't see it. I'll look inside tomorrow.

 

[Pete C]

Was talking to a buddy about this who ran it past a friend of his in the biz. He said that the gas valve will not open with the solenoid firing alone. Said it also needs to sense vacuum on the output.

This makes sense to me now.

 

[John Gayewski]

If you have voltage to the actual gas valve and it's not opening it'll need replaced. I seem to have to fix these gas valves frequently. They wil un stick amd work for a while then stick again. If you go to start looking for one that exact model will no longer be available. They should have a direct replacement. I usually go to the supply house for this.

 

[Fitter30]

Look at pages 3 & 37 3 is what your boiler looks like & 37 sequence of operation

WEIL-MCLAIN GOLD CGI 2 SERIES MANUAL Pdf Download

View and Download Weil-McLain GOLD CGI 2 SERIES manual online. Gas-Fired Water Boilers GOLD CGi Series 2. GOLD CGI 2 SERIES boiler pdf manual download. Also for: Gold cgi-25, Gold cgi-3, Gold cgi-4, Gold cgi-5, Gold cgi-6, Gold cgi-7, Gold cgi-8.

www.manualslib.com

 

[Jeff H Young]

seems an answer to the question hasent been given as far as . why would pilot light and main main gas click if blower wasent Creating sufficient flow to switch. im curious too because I try to understand these systems even though Im not working on them . Im thinking its not blower related at all , like john mentioned wouldnt have juice going to main burner or would it ?

 

[Pete C]

Thanks for the manual.

As I understand the sequence of operation, on page 37, I am back to my original thought. The inducer pressure switch has to be satisfied before it puts 24v to the main gas valve. Once the valve is powered, gas should flow. Period.
It didn't, for quite a while until it decided to.
This tells me I still have a questionable valve which will fail a again, eventually. Probably in January when it's 3 degrees out.

 

[Fitter30]

Thanks for the manual.

As I understand the sequence of operation, on page 37, I am back to my original thought. The inducer pressure switch has to be satisfied before it puts 24v to the main gas valve. Once the valve is powered, gas should flow. Period.
It didn't, for quite a while until it decided to.
This tells me I still have a questionable valve which will fail a again, eventually. Probably in January when it's 3 degrees out.

I'd replace it.

 

[Reach4]

If the terminals to the gas valve are accessible, I would run some temporary wire to where the meter can monitor the voltage across the valve's coil while the furnace is closed up. I am not saying that you should do that. It is just what I would do.

 

[Jeff H Young]

Thanks for the manual.

As I understand the sequence of operation, on page 37, I am back to my original thought. The inducer pressure switch has to be satisfied before it puts 24v to the main gas valve. Once the valve is powered, gas should flow. Period.
It didn't, for quite a while until it decided to.
This tells me I still have a questionable valve which will fail a again, eventually. Probably in January when it's 3 degrees out.

outcome ?

 

[Pete C]

The outcome is that the boiler is still working with the questionable gas valve. FIngers crossed, but not much confidence in the valve continuing to work.