Gas boiler heating house without call for heat
Comments
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That relay is available from any HVAC or Plumbing supplier. Here is the lowest cost one I could find that will do the job. Jard 24v. coil GP relay. If you want a name brand like White Rodgers or Honeywell you can spend another $10.00. If you purchase the OEM relay from the manufacturer you can really over pay for the same part. Here is an example of that from Weil McLain: 510-350-221
Lets hope that it is just that simple and you can get the part for under $20.00
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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I do have a multimeter. Somewhere 😂
The boiler only buzzes when the thermostat is set to Heat, so it’s only something I hear during heating season. I can’t remember if the buzzing is continuous when the thermostat is set to Heat or if it only buzzes if there’s an actual call for heat.
I suppose I could go upstairs and set the thermostat to Heat and jack up the set temperature as an experiment.The boiler temperature is back down to 100 so first I’m going to power the boiler back up without the CR relay and see what it does. Uno momento.
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I powered up the boiler with the CR relay removed. No damper opening, boiler does not fire up.
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This is the same CR relay that’s in my boiler now:
https://www.supplyhouse.com/Honeywell-R8222U1006-24-V-General-Purpose-Relay-with-DPST-N-O-switching
Pretty reasonable price
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Ok, here is where is gets more interesting and a multi-meter would help a lot. The relay has control.
So are the contacts welded closed or the relay is mechanically jammed in the active state (continuity or Ohm meter function on the multi-meter).
Or
Is there actually 24 VAC being applied to the coil of the relay due to a wiring error ? The 24 VAC (or lack of) could be measured at the relay socket relay coil pins.
So with the relay removed and applying the power everything is probably silent.
With the relay reinstalled, at the moment the power is applies do you here it pull in, a noticeable click ?
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
Won’t link for some reason
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Let’s find out! Hold on a sec
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@109A_5 Sure sounds like a click to me, see what you think:
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OK now I am puzzled, what caused the apparent delay from when the circuit breaker was closed to the click of the relay ???
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
The damper probably opening .
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
Yes, first I flipped the breakers on, then sat down and flipped the boiler switch on. That’s when you hear that little squeal, which is the damper opening, then a pause, then what I heard as a click, then the whoosh of the burners firing up
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I would say the Damper may be wired in wrong. Looking at the wiring diagram the 'click' the relay activating should be first then the damper should open. Once the Damper opens then the Boiler should fire up.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
Hmm. Let me compare the actual wiring for the damper with the diagram
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1. Thermostat closes in your case the thermostat via the Taco SR501
2. The coil of relay CR is energized.
3. Contacts CR1 and CR2 (CR2 not used in your case) are closed.
4. Damper opens, closing its 'End Switch' when fully open.
5. Gas valve is energized.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
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The Damper should not be activated until the relay CR is energized.
As near as I can tell it looks like the colors are correct. I wonder if the Damper was changed and it is different, what make and model is it ?
Also where do the coil wires of the relay go to, I suspect they are Blue and Black, from the pictures it looked correct.
Also the set of contacts wires used. Maybe the 24 VAC is bypassed around the relay contacts CR1, then when the relay is energized (Damper 'End Switch') the relay contacts effectively latch the circuit on forever.
Something is not right, the event sequence is wrong and it latches on forever.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
Damper model # is: RVGP-PC-6BKF
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The Damper wires are correct. There is some confusion as to what side of the connector is "To Damper"
I have added a red and a blue arrow for clarification above and in the photo.
The Y, G, Bk and BL are inside the black shrink wrap. Look past the black shrink wrap to see the wire colors
Regarding the Click you heard in the video just before the flame "woosh", that click is the sound of the gas valve clicking open. that was not the sound of the relay click.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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It almost seems to me like the Orange and the Blue in the drawing are reversed or their functionality in the Damper cable. But that does not explain all the symptoms.
I would disconnect this wire (Orange above, Red arrow below) with all the rest intact and see what it does. Does the Damper still open ?
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
To prove what the 'click' actually is you could disconnect the Gas Valve wire. If it is the Gas valve as @EdTheHeaterMan believes you are back to a stuck relay, or the relay's coil is being energized erroneously. Testing with a multi-meter may help, that is what I would do.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
i'd start with a meter to see if there is 24vac to the coil terminals and if the no terminals on the relay are indeed open.
it looks like the factory gave 0 f*$ks when they wired it but it doesn't look like anyone messed with it.
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which means it could be burned or chaffed and shorted somewhere too
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If you have a replacement relay, since they are so reasonable, just replace the part. I believe that will solve the problem.
@109A_5 has the Sequence of Operation correct on the diagram.
- Thermostat calls for heat
- SR 501 pulls in and
- the circulator operates
- The 5 and 6NO close to call for the boiler CR relay to operate.
- The boiler CR relay will close the CR1 and CR2 contacts.
- The burner will then operate if all the limits and the vent damper end switch are closed. (the vent damper end switch will make at the 6 pin plug at pin 5 and 2 to complete the circuit). I have added the wire color codes to this ladder diagram for clarity. The gas valve circuit starts at R on the transformer > CR1 > Y > Spill Switch > Water temperature limit > Rollout > Pin 5 on damper plug > Pin 2 on the damper plug > gas valve > back to C on the transformer.
- The thermostat circuit has only the CR relay coil on it
I believe there is an easier test for verifying the relay clicking.
Just take the 2 black wires at the wire nuts here and touch the wires together and then disconnect them. There should be a click every time the wires connect.and another click when disconnected. You can even send Morse Code with those wires if you know it. _ _ _ . . . _ _ _
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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If you check the relay with a Multi-meter.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
@EdTheHeaterMan OSO . . _ _ . .
@FrankMaraschino You could also jumper here. The thing is even if the relay clicks it still could be defective. The meter will tell you what is really going on in the circuit, but you have to work on it live and that has risks of its own.
With relay in the socket I believe you can measure the coil voltage here, Yellow arrows.
Testing a Bad Honeywell General Purpose Relay and Taking Apart to See the Burn Marks!
https://youtu.be/u_7K5GJoxBkNational - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
@109A_5 Great Video! I believe the opposite happened to @FrankMaraschino's relay. The contacts are not open like in the video, but they are closed or welded together so they do not open when the coil is not energized.
I just thought of a fix for this that will not need any parts. If you use the 5 and 6NO on the SR501 to do what that general purpose relay is supposed to do.
Diagram to follow:
Since all the CR1 contacts on the problem relay do is connect Y to R on the Transformer terminal board, then we can just use 5 and 6NO to connect R to Y on the transformer terminal board. The SR501 is already doing what the CR2 contacts are supposed to be doing, just use the SR501 to do both jobs.
It is easy to do… Just take the wire that is connected to G on the transformer terminal board and place that wire on Y on the transformer terminal board. Very simple fix…. Just remember to leave the CR relay out of the socket.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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@109A_5 I removed the CR relay and tested resistance using my multimeter, following the procedure in the video you linked. The results:
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For proof of concept of @EdTheHeaterMan's no parts required fix, remove the 'CR' relay and jumpering R to Y should have control of the boiler. R to Y closed boiler fires, jumper removed R to Y open the boiler shuts down. Seems promising since the boiler did not fire with the 'CR' relay removed.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System1 -
O means Open or Zero resistance (0.0 Ohms) ? If Zero Ohms the relay is bad. Probably a mechanical problem if both sets of contacts are closed.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
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relay is bad. once one contact welds it can hold the other contact closed or it could be a broken spring or dirt making it stick.
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I ordered a replacement from Supply House. Will arrive tomorrow
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I think OL means open and zero (0.00) means closed.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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Just making sure, OL without the L is O. O could mean Open.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
@109A_5 You give me ideas and I try to give you ideas back. I think the SR501 can do the job. …and it is just moving one wire on the transformer terminal plate.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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Either way should work, although having relays in series is just more stuff to fail. However it keeps the boiler wiring consistent with the OEM drawings.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System
1 -
@EdTheHeaterMan, Yes I agree. Either way should work, having relays in series is just more stuff to fail when you need heat. However it keeps the boiler wiring consistent with the OEM drawings.
Not up to me it is @FrankMaraschino decision. Maybe a future plan 'B'.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System1 -
You need to know your meter…. on my digital meter 000.0 ohms means no resistance. Closed circuit. For an open circuit my meter would read OL which was translated from the infinity symbol (∞) on the old analogue meters in the original instruction manuals. But that was back in the day when old farts were converting from analogue Simpson multi meters to Digital stuff and they thought we needed to be told that ∞ = OL.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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Unless there was a wiring error or a shorted thermostat or wire the CR relay pretty much had to be the issue.
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That's the same as my Ideal meter, which also has an optional audio tone to indicate anything other than an open circuit
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