Hi all,

I'm new here, so bear with me, please!

I have a Weil-McLain boiler (M#-CG-8-SPDN, 245,000 BTU) that I use to heat my home. I attempted to start it last week, but the pilot light was out. I tried to re-light it, to no avail. I removed and 'shined up' the thermocouple, but that did no good.

Assuming that the thermocouple was bad, I removed it and replaced it with a new Honeywell universal unit. That did not work as well. I called the local Weil-McLain dealer to purchase a new gas valve, since the problem seems to lie here. Now here's the problem:

That particular boiler had one of two gas valves on it, a Honeywell (which I have) or a White-Rogers (which the vendor had in stock). I bought it. The problem is that there were no instructions/schematics with the unit. Other than the wiring, installation is very straightforward: gas in/out (3/4" NPT), pilot line, and thermocouple. However, the configuration of the tongue terminals is different between the manufacturers. The White-Rogers terminals (M#-36C74, Type-474) are labelled 1 through 4. Terminal 1 is a pair of tongue terminals standing alone. Terminal 2 has a black jumper fron terminal 4, which has a brown wire from the gas valve also connected to it. Terminal 3 is shares with a yellow wire from the valve. Terminal 4 is used up with the black jumper and the brown wire.

My best guess is this: Terminal 1 is not used. That leaves terminals 2 & 3. Since 2 & 4 are jumpered together, I'm assuming that that should have the hot wire from the transformer (black) going to terminal 2. The remaining wire going to the gas valve from the damper control (red) should go to terminal 3.

This seems logical to me, but I don't want to screw up and ruin a $100 gas valve (plus the vendor has no more gas valves in stock). HELP!

Thanks!

Ron

P.S.:

I'm not exactly a rookie at this. I was a member of Engineers Local #399 (AFL-CIO) for over 20 years before retiring last year. I'm HVAC/R certified through a two-year course sponsored by the union which I took. I worked maintenance (electrical/pneumatic/hydraulic) at the heating plant which I worked at the local university for 23 years.

Got to this site and type in the model # of the Honeywell valve you have. Lower right corner.

Default - Honeywell Environmental And Combustion Controls

Thanks hvac1000!

Does White-Rogers have a similar site?

Ron

White-Rodgers, Emerson Climate Technologies

Quote:

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Originally Posted by RonGH

Hi all,

I'm new here, so bear with me, please!

I have a Weil-McLain boiler (M#-CG-8-SPDN, 245,000 BTU) that I use to heat my home. I attempted to start it last week, but the pilot light was out. I tried to re-light it, to no avail. I removed and 'shined up' the thermocouple, but that did no good.

Assuming that the thermocouple was bad, I removed it and replaced it with a new Honeywell universal unit. That did not work as well. I called the local Weil-McLain dealer to purchase a new gas valve, since the problem seems to lie here. Now here's the problem:

That particular boiler had one of two gas valves on it, a Honeywell (which I have) or a White-Rogers (which the vendor had in stock). I bought it. The problem is that there were no instructions/schematics with the unit. Other than the wiring, installation is very straightforward: gas in/out (3/4" NPT), pilot line, and thermocouple. However, the configuration of the tongue terminals is different between the manufacturers. The White-Rogers terminals (M#-36C74, Type-474) are labelled 1 thru 4. Terminal 1 is a pair of tongue terminals standing alone. Terminal 2 has a black jumper fron terminal 4, which has a brown wire from the gas valve also connected to it. Terminal 3 is shares with a yellow wire from the valve. Terminal 4 is used up with the black jumper and the brown wire.

My best guess is this: Terminal 1 is not used. That leaves terminals 2 & 3. Since 2 & 4 are jumpered togehter, I'm assuming that that should have the hot wire from the transformer (black) going to terminal 2. The remaining wire going to the gas valve from the damper control (red) should go to terminal 3.

This seems logical to me, but I don't want to screw up and ruin a $100 gas valve (plus the vendor has no more gas valves in stock). HELP!!

Thanks!

Ron

P.S.:

I'm not exactly a rookie at this. I was a member of Engineers Local #399 (AFL-CIO) for over 20 years before retiring last year. I'm HVAC/R certified through a two-year course sponsored by the union which I took. I worked maintenance (electrical/pneumatic/hydraulic) at the heating plant which I worked at the local university for 23 years.

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Post your fax number and I'll send you the schematic for the Weil-McLain

tsa7man,

Sorry, I don't have a fax. Could you possibly just send it as an attachment?

Thanks a bunch!

Ron

You can get this same information from the Weil-McLain web site under the headings professionals, product manuals, wiring diagrams, look for the CG, I don't know which series you have... so if my attachments work correctly, they both are here...

Thanks, I found thas site. My unit is a CG-8-SPDN, not the same unit, but close (wire colors match, anyway). I also found a CLOSE White-Rogers gas valve on their web site. I'm still squeemish about wiring it up. It looks like terminals 1 & 2 control the main gas valve. There is (was) a jumper between terminals 2 & 4, but the directions said no jumpers for standing pilots, so I removed it. The Weil-McLain schematic doesn't give specific terminals for the black and red wires. I'm thinking that since it is a coil (on the main gas), it doesn't really matter which side of the coil the power comes in. Does that make sense? I wasn't able to access the Honeywell schematics. It said my computer was unable to translate the text.

I'm about ready to try my hunch (treminals 1 & 2). I just hate to think that I might burn up a coil and fry the gas valve:eek:. Oh well, no pain, no gain! Thanks for your help! If you think of anything else, please ping.

Thanks again!

Ron