I have a this boiler that starting having problems last year with igniter not working. I pulled the igniter out and found black soot falling out. Then it started to flameout. I cleaned the combustion chamber out with a wired brush and vacuumed.Previous owner said he never cleaned it out.
I also replaced the burner(flameholder) cause it had a few cracks in it and replaced the gas valve as a precautionary. It worked fine for 2 weeks and now it has a start up problem. It cycles through a few times then the Red Flame light on the control board starts flashing. I take power off for 10-15 seconds & with the timer off and it starts right up and works great for a few days.
I replaced the igniter, no more soot or particles falling out of the combustion chamber and set the timer back 4 minutes.
On a cold start the igniter reads 54 ohms with a current draw of 3.8 amps.
On a warm start the igniter reads 68 ohms with a 3.8 current draw. The gas valve reads approx. 25v across.
The stack switch seems to operate normal.
I sealed the gas flue with speed tape.
I have a pressure diff sw on order cause its leaking water at the housing.
Could some lend a hand in my troubleshooting?
Those boilers are really frustrating to work on. They have fancy controls that really don't tell you what is going on.
I had a similar experience that ended up being a bad gas valve harness.
Any chance you can talk the owner into a replacement? The exchangers usually fail about now.