Munchkin Problem

Alan (California Radiant) Forbes

I service quite a few Munchkins and every now and then, I come across a problem that I have no answer for. The most recent is a 12-year old 140M with a flashing light circuit board (Rev. 1). The blower had died and a capacitor on the circuit board looked as though it had blown up. I replaced the circuit board with a new flashing light circuit board (supplier had it in stock and it would have taken awhile to get a 926 upgrade kit from the factory); also replaced the blower, igniter, rectification probe, target wall and refractory.

When I turn on the boiler, the burner lights off and then steps down to a lower flame and then turns off; over and over again. If I let it go long enough, the boiler will sometimes stay on and then turn off when it reaches limit. More often than not, the boiler will go into error mode, showing flashing lights to signify "Ignition Fault (No Flame)".

One guy at Munchkin tech. support said to clean the burner which we did and it didn't help. I don't think it's a problem with the burner since it lights off fine every time, but fails to stay lit. Brent at Munchkin tech. support this morning said the new blowers feed back a lot of information back to the circuit board and it may be too much information for the old, rev. 1 board; that I need to upgrade the board. The times are few and far between when I get accurate information from Brent, so I am not confident with his suggestion.

Any ideas?

Rich_49

Have you checked signals throughout the 925 Alan ?

Alan (California Radiant) Forbes

No I haven't. How do I do that on a flashing light board?

Rich_49

HTP Tech will be happy to walk you through the procedure . I'm sure Brent would be glad to do it while you are next to the boiler .

Mark Eatherton

Randy Wakeman with Priest-Zimmerman (Manufacturers Rep) in Denver knows these gems inside out and upside down. Tell him I sent you. It sounds to me like the stack pressure differential switch is dropping out, and the control is recycling. That isn't something that would send the board into alarm status. You can't bypass it or you will get an alarm output. If it see's a closed circuit there before it's supposed to, it locks out.

ME

hot_rod

What about Morgan Muir, right in you backyards? He's been a HTP rep since early on.

Charlie from wmass

.not just a bad flame sensor? I start simple.

Jr_12

On your list of parts I didn't see the burner gasket? What part numbers did you get for igniter/sensor? I would make sure the burner screws are cleaned up and get a combustion analyzer on it when she stay lit. Unfortunately there is no way to force high/low fire on these so it is a waiting game.

Rich_49

Sounds like Alan may have used the 7250P-995 rebuild kit which includes that gasket .

Alan (California Radiant) Forbes

Thank you, everyone for your comments and advice. In the end, the owner purchased a 926 upgrade kit online; we installed it and the boiler is now working properly.

All of the parts we previously used were good and the gas/air mix was within spec's. which tells me that for some reason, this little Munchie just wanted a control upgrade. Yes, I'll admit it: Brent was right.

One little glitch along the way was when we first did the upgrade, we got an E02 error message on the control. It was after hours and I couldn't rouse any technical support and the owner's had to go a day without hot water. Come to find out that E02 means that the circuit board was not programmed properly at the (online) supplier. I had to take it down to my local supplier and have them program it.

Hot Rod: Morgan has semi-retired and doesn't work at HSC on a regular basis anymore. He's got some irons in the fire with Hoyt Corbett as well.