Munchkin 199M Going \"Bang\" On start-up

Paul Rohrs_7

This has happened to me a few times. Generally it happens after servicing the boiler and cleaning the spark-ignitor and/or rectification probe.

The refractory material that covers the combustion chamber cover has the ability to ground out the spark-ignitor, so as the combustion chamber fills with the gas/air mix and we the spark is delayed intermittantly,......bang. It sounds like a shotgun blast and can really test ones bladder control.

After servicing the ignitor, I will bevel off the refractory (ever so slightly) where the spark-ignitor enters the combustion chamber and I isolate contact between the two. This has always solved it for me.

Paul

Glenn Harrison_2

Call came in as Burner going bang and won't stay lit.

I'm posting this as information, as I haven't seen this problem posted before.

Anyways, the call came in as no domestic hot water, and homeowner noticed Munchkin lites with a bang and won't stay lit. I checked it out and it "banged" to the point the floor shook a little. I pulled the burner, HX was OK as well as the burner head, electrode, and flame sensor. I then looked at the burner motor, and noticed the swirl plate between the Dungs gas valve and the motor was brittle. I separated the gas valve and found the swirl plate was actually decayed and cracked in the middle.

Ordered a new swirl plate and replaced, and now it s running fine.

Anybody else seen this on a Munchkin? Just curious

bobbyg_8

It's been mentioned here on the Wall before. It is important to correct the situation that caused the swirl plate to deteriorate or it will do it again.

Negative pressure in the room with the lid being loose (weatherstrip to tighten up) and correct the negative pressure. This is but one reason this may be occuring.

Call the factory for more suggestions.

Paul, I know what you mean about the bladder control, well said. :-)