Faulty spill switch?

Michael Rogers

So the tstat called and I heard the relay on my 2 year old WM CGa-4 kick in. Then instead of a nice quiet woosh of combustion it sounded like light roaring. I go downstairs right away and it is loud, open the door to the boiler room and the room is cooking warm, humid and "smells" of combustion. I move out of the room right away and shut her down and open the bsmt. windows. I go back in, and the walls are damp with moisture from the exhaust, the stack to the hood it hot, but after the draft hood is cool. Right away I think that there is a blockage in the venting, but I turn it back on again to check and it is fine and the damper works fine and exhaust gasses are now venting. I went up on the roof and pulled the cap off and looked down the liner and it is clear all the way. I have now just finished putting a lighter to the inside of the hood right at the spill switch (Because it should have tripped) and left the lighter there for at least 30 seconds (too hot to touch), well it never tripped. Is this a common thing? I will order a new one tomorrow but still find this odd. The Dryer was on but is in another room and it along with the water heater running at the same time as the boiler have never been a problem before. We have made no new improvements to the tighness of the house and it is not windy (34°F & 100%humidity). Sorry for the long post but family saftey is my concern. Oh, just moved the CO detector into the boiler room. Thank you in advance for the replies.

bob young

spill swich.

sometimes spill switchs when they trip its a one shot deal & must be replaced. try the larger deluxe fields model. seems more reliable. annoying little control but when you need it nothing else will do.

ed wallace

spill switch

check the cap on the chimney if its to far down into chimney it will cause a problem

Mark Eatherton

Spill versus roll out switch...

The spill switch on newer boilers is a manual rest type of bi-metal switch. The rollout protection switch is supposed to be a one shot non resetable fuse type of protection device. If it blows, you've got a serious problem that needs immediate and direct attention.

The draft hood spill switch can be an occasional nuisance lockout caused by whole house fans, GenAire grills, and more. Bi-metal switches are notoriously sloppy.

First, try unplugging one leg of the switch and see if the boiler still fires. If yes, someone has bypassed the switch. Fix the wiring and get yourself a new manual reset spill out switch. If it continues to spill and trip, consider eliminating the open draft relief hood and installing a barometric damper with spill switch attached.

If you do a deep set back at night, and the boiler cools off, it is probably having a tough time overcoming the slug of cold air in the vent stack, and the barometric damper should take care of that problem.

ME

Mark Eatherton

Light roaring....

Sounds like flash back into the burner tube assemblies, and that is guaranteed to generate LOTS of CO.

Look at the face of the burner when it is roaring. If the flame is inside the burner, you have a burner pressure issue.

All appliances, by code, are allowed to spill products of combustion for a short period of time until they establish draft, but it should not be so long that you have condensation on the walls of the mechanical room...

ME