Spill switch activates once a week

qemls29

My 30 years old Burnham IN6 gas steam heat boiler has been shutting down once a week for the past five weeks. Does anyone know why the spill switch would activate almost exactly once a week? I tried installing a chimney cap, changing the gas valve, changing the spill switch, changing the damper (it was locked in the open position), checking the chimney ducts, and moving the spill switch. Thanks.

Alan (California Radiant) Forbes

Strange that it should start happening after 30 years. And you've done everything I would suggest except a thorough examination/cleaning of the entire length of the flue. Can you look down the entire length from the roof?

ChrisJ

Any new exhaust hoods installed or modifications to the building such as spray foam, sealing drafts etc?

SuperTech

Maybe you have something wrong with the heat exchanger and it's causing the flue to overheat? A thorough inspection of the heat exchanger and venting then a complete combustion analysis should be performed. That's an awfully old furnace, I'd be concerned about its integrity.

qemls29

Reply to "Alan (California Radiant) Forbes": Yes, the chimney is clean from the roof down to the basement. And, the pipes to the boiler are clear. Thanks.

qemls29

Reply to "ChrisJ": No new exhaust hoods installed or modifications to the building such as spray foam, sealing drafts etc. Thanks.

qemls29

Reply to "SuperTech": Okay, I'll ask my guy to inspect the heat exchanger. Thanks.

qemls29

Today, I swapped out the generic SP220 spill switch to one made by the manufacturer of the Burnham IN6 boiler. Hope it helps.

HVACNUT

Is it a standing pilot?
If so, is the knockout open in the flue damper?

Alan (California Radiant) Forbes

HVACNUT said:

Is it a standing pilot?

If so, is the knockout open in the flue damper?

That's a good one! Do you think it would generate enough heat to trip the fuse?

icy78

Spill switch is open because of flue gas spillage. Flue gas spillage is caused by back drafting and or too much draft in the flue. When you get too much draft it makes an air curtain across your draft Hood and the flue gas spills out the easiest way which would be back into the space. For that type of installation you need the draft Hood removed or capped off and a barometric installed with a spill switch.
This needs to be installed and set up by a professional with a combustion analyzer that knows what the analyzer is telling him.

The combustion analyzer combined with a draft gauge ,will also determine if what I mentioned above is what you need.

HVACNUT

> @Alan (California Radiant) Forbes said:
>
> That's a good one! Do you think it would generate enough heat to trip the fuse?

I don't know. I thought it might be plausible. I've been in many small boiler rooms with a standing pilot and I'm surprised how hot the block can get.

Robert O'Brien

I'd do a worse case depressurization test.

SuperTech

> @Robert O'Brien said:
> I'd do a worse case depressurization test.

Exactly. The spill switch is obviously doing its job, which is a bad thing. It's not a faulty switch, gas valve or other component. Combustion by products are entering the home. If this isn't figured out it is time to hire someone who can.

DZoro

30 years working fine.
Clear chimney, so that is good to go.
Boiler heat exchanger, has someone actually ran brushes and physically cleaned it. Not just a poof with a shop vac, but actually brushed it out top to bottom?
Pretty sure the safety is doing its job.
D

icy78

> @DZoro said:
> 30 years working fine.
> Clear chimney, so that is good to go.
> Boiler heat exchanger, has someone actually ran brushes and physically cleaned it. Not just a poof with a shop vac, but actually brushed it out top to bottom?
> Pretty sure the safety is doing its job.
> D

30 years working fine,

Could also mean that it heated, but maybe Spilled Out the other side of the draft hood , and now something has changed and it's spilling out this side of the draft Hood. Or something in the house changed and with certain wind pressure, it now trips.

HVACNUT

Something changed. Whether its combustion, chimney or free air related, it's time to see pics of combustion and draft tests and go from there. You need boots on the ground.

captainco

Over time buildings shift and settle. What once was a tighter home is now a looser home. The spill switch is doing its job now someone that understands venting, combustion air, combustion testing needs to come in and identify the real problem.

SuperTech

The fact is that combustion byproducts like carbon monoxide are entering his home. I wonder the frequency of the back drafting? I would definitely look into buying a low level CO detectors, and absolutely call a trained professional.

qemls29

The spill switch activated again after turning on the boiler 20 days ago. Could someone recommend a contractor in Brooklyn, NY, to troubleshoot the problem? Thanks.

neilc

blue bar, top of the thread,
https://heatinghelp.com/find-a-contractor/

Tim McElwain

You need a professional to come and do a combustion analysis. Ask them if they do that (combustion testing) before hiring them.