Weil-McLain gas boiler continues to run

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Old 10-20-10, 06:37 AM
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Weil-McLain gas boiler continues to run

My Weil-McLain GOLD CGa gas fired water boiler sometimes fails to shut down after thermostat temp is achieved. When this occurs turning the thermostat all the way down has no affect. I replaced wiring from thermostat to boiler. Then replaced thermostat with a New Honeywell CT87N. I wired it to pins R & W.
The unit has worked fine for about a week, cycling on and of as needed. Then it started acting up again staying on, until I open the breaker to the boiler.
What should I test or replace?
 
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Old 10-20-10, 04:38 PM
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Wow... another one... it seems as though this season has brought a rash of 'stuck on' systems!

What's the full model number of your boiler... from the dataplate on the boiler?

Do you know if it has a continuous standing pilot, or a spark ignition? (which one?)
 
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Old 10-21-10, 05:29 AM
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Weil - McLain

The model # is CGA-4-SPDN
It has a continuous standing pilot.
 
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Old 10-21-10, 03:08 PM
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In that case, look inside your boiler for something that looks like this:


image courtesy Honewell.com

The item on the bottom, the one with the wire 'bail' holding it in is a relay. There's a good possibility that relay is sticking intermittently.

W-M's product literature does not give the Honeywell equivalent part number so it isn't possible to tell you the 'cheap' way out... you can buy a whole new assembly for about $50 and change, but all you need to do is change that $15 PLUG IN RELAY. That 'bail' swings to the side, and that relay will unplug from the socket base. Plug a new one in and yer done...

IF that's the problem. There is not guarantee, only a GUESS.

Wanna take a look at the relay and see if there are any part numbers on it? If you find something that starts with R8222______, then we can find you a replacement... or any other numbers that you can find.
 

Last edited by NJT; 10-21-10 at 03:46 PM.
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Old 10-21-10, 03:30 PM
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FOUND the Honeywell number!

For the entire unit, the Honeywell number is R8285D-1000

There's a White-Rogers number for the same part: 631-9001

Then, there's a White-Rogers number for the relay only: 91-322000-11000

I THINK this is the correct relay for your control... VERIFY before using, do NOT trust a stranger on the internet!

Patriot Supply - R8222U1079
 

Last edited by NJT; 10-21-10 at 03:46 PM.
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Old 10-22-10, 07:55 AM
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I removed relay and it has the following label :
W-R/RBM
91-1120006-11000
COIL 24V 50/60 Hz

12AFL 60ALR 125V
6AFL 36ALR 250V
21A RES 277VAC
ASSEMBLED IN MEXICO

I took a continuity test across terminals 1 & 3
0 resistance

And across terminals 4 & 6
0 resistance

If I am reading the diagram on the back of the relay correctly, they are both normally open circuits. and the relay is stuck closed



I am going to replace the relay, if I can find one locally and will post the results.
 
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Old 10-22-10, 02:49 PM
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Yes, 1&3 and 4&6 should be the normally open contacts.

I'm reasonably sure that the Honeywell number will work too. If you hit a supply house they should have a cross reference to look it up. They may also have other brands, such as MARS that will work.

If you are in the Northeast, Patriot will get it to you in a day if you order... about $15 plus shipping... which could be another $10 ... so if the supply house wants $40, you are better off ordering on line.
 
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Old 11-03-10, 06:37 AM
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Heater is working GREAT !!!


Thanks NJ

I received the part from Patriot yesterday, and after 24 hours of operation all is well.
Thanks again for pointing me in the right direction for troubleshooting the unit, the part number and supplier info.
 
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Old 11-03-10, 06:25 PM
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Glad it all worked out well for ya! Thanks for stopping back to let us know... good luck!
 
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