Repetitive Flame Loss Error

samfiller

I have a Peerless 63/64 with a Capable Controls intermittent pilot ignition series 5.

After the boiler is running for 10 minutes or so the flame turns off, the igniter relights it and its last about 3-4 seconds and this repeats itself - eventually (it may be after 10 tries) the unit completely shuts down for 5 minutes and this cycle start over again -
Based on the manual https://www.capablecontrols.com/series-5-ignition-control-instruction-manual
It sounds like its detecting flame loss - I dont see a flame sensor (which i assume would be the issue in this case?)

Any thoughts?

Thanks!

JUGHNE

The flame sensor may be part of the spark igniter or the igniter itself. It needs to be clean of scale etc. A dollar bill is sometimes used to clean and polish the surfaces.

That is only 1/2 of the flame sensor the other 1/2 is a ground return path from the pilot to the control module.
That could be just a loose connection. Removing and replacing push on terminals may restore the contact.

samfiller

Which part need to be cleaned?

gfrbrookline

Check your gas pressure, before the gas line was replaced on my street with a larger main I was plagued with the boiler shutting on low gas pressure.

unclejohn

The skinny shiny rod at the end of the white wire.

samfiller

@gfrbrookline - I will look into that.

@unclejohn - Thank you, I "cleaned" it so far it didnt help.

Should I try replacing?

JUGHNE

The other path of the flame sensing circuit is thru the pilot flame to ground. This is flame rectification, AC current passes thru the sensor and then when the flame is in contact with it the current changes to DC current. The control module senses the DC and allows the pilot and main burner to stay on. If the flame is lost for just 1-2 seconds it will shut down.

I would remove the pilot assembly, there is a clip holding the sensor in place. With that out of the way you can unscrew the tubing....then unscrew the fitting that the tubing was screwed into. This will expose the gas orifice. Might be a separate little thimble looking piece the size of a 22 bullet. Or it may be built into the fitting. Just do not lose it. It will have a pin hole in it that needs to be clear....hold up to a bright light to check. Do not enlarge.
Then brush the 2 wings for the pilot burner and blow out with air. Put the tubing back on the burner and make sure you can blow thru it.
Replace the sensor into the pilot and reinstall the whole thing.
The other end of the sensor must have a good connection.
Pull/push all the connections on the control module to get a new "bite". The entire furnace must have a good ground connection all the way back to the CB panel.

For me this is the first step in troubleshooting. Then look farther if need be.

samfiller

@JUGHNE
Thank you, took it all part it looked clean used some "canned" air to be sure.
The ground looks to the control board.
It still seems to be an issue..

Thanks

JUGHNE

When only pilot is on, do you see flame coming from both wings of the pilot burner. The pilot flame may be adjusted higher also.

And as said above sometimes the gas pressure drops as weather gets colder.

samfiller

@JUGHNE
Its not possible to see the igniter as its too high up past visibility - even if you are lying down...

Pressure can always be an issue, but it seams to be consistent after 10-15 minutes, I assume pressure would be an issue right away or at certain times of the day.

JUGHNE

Your wiring diagrams posted show a separate flame sensor wire and separate spark wire.
Is there a diagram posted on the door or cabinet?