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Brian HVAC Guy
Brian HVAC Guy, HVAC Technician
Category: HVAC
Satisfied Customers: 942
Experience:  I have been an HVAC/R mechanic/technician for 30+ years.
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I have a circa 1987 Dunkirk boiler. Honeywell l8148e

Customer Question

I have a circa 1987 Dunkirk boiler. Honeywell l8148e aquastat and a y8610u replacement kit including the new gas valve and control. Boiler has a power inducer vent. Installed by a pro, and still no heat. Ignitor will spark, but no pilot or main valve opening. Tech left the jumper in for vent damper and says it should stay in or I'm screwed. I paid 500 for the parts and haven't got a bill for labor yet. Now he says it's the ignitor not sending the signal back to the control. It is well grounded and about a month old. I can't get tech to come back and it is 15 degrees outside. Help.
Submitted: 1 year ago.
Category: HVAC
Expert:  Brian HVAC Guy replied 1 year ago.

Hi Pete, I'm Brian and I'm here to help! I'm sorry you're having trouble with your boiler and tech. I'll do my best to help.

Was the pilot burner assembly replaced at the same time the gas valve and control was installed? If I understand correctly the ignitor is a month old so all of these things were installed a month ago? Also, what level of help are you looking for? Do you have a volt meter and are you comfortable checking voltages on energized equipment?

Thanks,

Brian

Customer: replied 1 year ago.
The ignitor is a month old. All the other parts were installed Sunday.
Expert:  Brian HVAC Guy replied 1 year ago.

Ok thanks. You say "ignitor will spark, but no pilot or main valve opening", if you have no pilot flame then the issue can't be the ignitor not sending a signal back to the controller. If you do have a pilot flame then maybe that could be the issue. The fact that it's sparking, tells us that everything in the circuit is fine for ignition. At the point where the ignitor is sparking, the pilot valve in the gas valve should be open. You should have a voltage signal from the control to the gas valve between MV/PV and PV. If all that has been met and the gas valve has a voltage signal at PV then the pilot valve should be open and flowing gas to the pilot burner orifice. If you don't have voltage to the gas valve then there is a problem with the wiring somewhere or a remote possibility a problem with the control. If you do have a voltage signal at PV on the gas valve but there is still no pilot flame then perhaps there is a gas flow problem. The new pilot orifice may be at issue or there may be an issue with gas pressure.

Has the new control/valve/pilot burner worked at all since Sunday?

Customer: replied 1 year ago.
It fired once and then quit. Should the vent damper jumper be removed if i have a forced induction motor in the chimney which is actually part of the boiler
Expert:  Brian HVAC Guy replied 1 year ago.

I can't be sure of that but it's doubtful. I can't find the wiring diagram for your boiler anywhere. That would tell me definitively. Was your new controller/gas valve a retrofit or an exact replacement?

Expert:  Brian HVAC Guy replied 1 year ago.

If your boiler has a legible wiring diagram and you can take a legible picture of it and upload it here using the 'Attach Files' button, that would be extremely helpful!

Customer: replied 1 year ago.
Here is pic of old gas valve and controler
Customer: replied 1 year ago.
Here is pic of new y8610u kit
Customer: replied 1 year ago.
Pic of boiler
Customer: replied 1 year ago.
Pic of jumper for vent damper with green wire
Customer: replied 1 year ago.
Aquastat
Expert:  Brian HVAC Guy replied 1 year ago.

Thanks for those pics! It definitely helps me to get on the same page as you. I would have to say the vent damper jumper is not the issue. It would appear your inducer is controlled by the boiler control. The fact that the new control is sending a spark is indicative that all is well in the electrical circuit to the point of ignition. I see you have a meter there. While the new controller is sending spark can you tell me what the voltage is on the gas valve terminals between terminals MV/PV and PV please?

Customer: replied 1 year ago.
Does this have effect
Customer: replied 1 year ago.
It's bouncing all over from 2.8dc to over 4.
Expert:  Brian HVAC Guy replied 1 year ago.

Those switches have an effect on how long the controller waits to provide spark after the inducer fan starts (pre-purge) and 2) how long the unit will spark and wait for a flame sense from the pilot burner before soft lockout/time out retry for ignition (which is a 5 minute wait then retry. The default of no pre-purge and 90 second trial should be fine for your boiler. The settings for that are OFF/OFF.

Let me study your pics for a bit. Please bear with me.

Thanks,

Brian

Expert:  Brian HVAC Guy replied 1 year ago.

Ok, I want you to power down the power to all controls on the boiler. Wait one minute, then power back up. Ensure the boiler is set to run. The inducer fan should start and then when the control is sending spark to the ignitor, would you please measure the voltage between terminals TH-W and 24v GND. Then measure again between terminals MV/PV and PV. Just to be sure, you are measuring with one meter lead on MV/PV and one meter lead on PV. Don't worry about the MV terminal right now.

This sounds like your controller is malfunctioning but I want to be really sure!

Thanks,

Brian

Customer: replied 1 year ago.
Now I'm getting no spark and no voltage. I'm done. Which controller? They are all brand new.
Expert:  Brian HVAC Guy replied 1 year ago.

I'm sorry, the controller I'm referring to is the Y8610U. Now it seems we have a different problem upstream of that controller. When you powered back up, what came on? If the aquastat (the L8148) should have brought on your circulation pump and inducer fan. Did those two components operate ok? From there, the aquastat should have sent voltage to the y8610 on terminal TH-W to start ignition. That's where we were at before when you had spark. What has changed? Bear in mind there may be time delays for these components.