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Rick, HVAC Supervisor
Category: HVAC
Satisfied Customers: 21547
Experience:  40+ yrs. experience as a licensed oil & gas technician.
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, Blocked vent switch has tripped a few times on very

Customer Question

JA: Thanks. Can you give me any more details about your issue?
Customer: Blocked vent switch has tripped a few times on very cold nights. Boiler company came, said nothing was wrong so I should check chimney. Chimney guy knew it was a new chimney, I checked it anyway and there is no blockage. Boiler is gas Buderus, installed new about 1.4 years ago, and new chimney at same time.
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Submitted: 1 year ago.
Category: HVAC
Expert:  Rick replied 1 year ago.

Welcome to Just Answer, my name is ***** ***** I will do my best to help you with your issue. If my initial response doesn’t answer your question then let me know and we can continue our conversation.

Since neither the plumber or the chimney guy found anything wrong I'd replace the switch. On very cold nights you'll have little to no draft initially (before the burners come on with a cold boiler) but that shouldn't trip the switch unless the switch calibration is off.

Customer: replied 1 year ago.
Do you think the boiler company should do that or should I just try to get a replacement? It would be nice if they did it at cost since I already paid them for the first visit when they said nothing was wrong.
Customer: replied 1 year ago.
Or, can I verify that the switch is not functioning properly somehow?
Expert:  Rick replied 1 year ago.

It's a pretty simple replacement that shouldn't take more than 5 or 10 minutes and it's something you can do yourself if you're inclined to. Then you won't have to battle the boiler guy over doing it at cost. There's no way you can verify proper switch operation other than the one you have now is apparently tripping when it shouldn't.

Customer: replied 1 year ago.
Ok, I'll try that. Could the damper be malfunctioning? It seems to be moving properly. If I understand, you're thinking that the cold nights make such a temperature difference that the back draft ends up causing the switch to trip, probably tripping too soon, is that right?
Customer: replied 1 year ago.
Would switches be available at Home Depot or would I need a specialty shop?
Expert:  Rick replied 1 year ago.

While anything is possible it's very unlikely that a damper this new would work sometimes and not others. I didn't say that the lack of a decent draft (never mentioned a downdraft) would or should cause the switch to trip. I was only pointing out the only relevant difference in conditions since you mentioned the cold weather. You'll have to go to a plumbing supply house that sell Buderus to get the right switch

Expert:  Rick replied 1 year ago.

Do you have any more questions?

Customer: replied 1 year ago.
That's all
Expert:  Rick replied 1 year ago.

I'd appreciate a favorable rating