Gas boiler pilot goes out intermittently

JaredG

Hi all,



I've got a recurring problem that I hope you'll be able to help with, as it's getting cold here in the Northeast. I have a PB gas boiler (<a href="http://www.johnstonesupply.com/storefront/peerless/hydronics-plumbing/equipment/boilers/hydronics-plumbing/equipment/boilers/gas-fired//prodl98-509.html">http://www.johnstonesupply.com/storefront/peerless/hydronics-plumbing/equipment/boilers/hydronics-plumbing/equipment/boilers/gas-fired//prodl98-509.html</a>) on which the pilot goes out intermittently.



Sometimes it will happen once a day, sometimes once a week. The furnace will sound like it's working and I can hear it throughout the house, but there's no heat because the pilot isn't lit.  There's a small red button up in the opening between the two front panels (see at top of photo, between two wires) that will light the pilot when it goes out, but that's no help when it goes out at night or when we're away from home and the house gets frigid.



Any help is greatly appreciated!



Many thanks,

Jared

ProfessorTim

Call a Professional

No offense, Jared, but I get the sense you are not a professional HVAC technician?



Modern gas boilers will shut themselves down if they detect a condition where it is unsafe to try to operate.  For some "less serious" conditions the system will retry after a delay in case it was an intermittent issue.  If a very serious condition is detected it will shut down and stay down.



Those switches with the little red buttons are reserved for the very serious conditions and if pressing that button alone is truly what makes the system restart then you need to have a professional come in and service it.  Tell them everything you've observed, heard and done.



Best Regards,

Tim

JaredG

None taken, of course.

Thanks for your response, Tim!



I had a similar problem last year and did call a major area HVAC company, which sent a tech who said it was just a malfunctioning safety switch and he would bypass it while ordering the new part required. Despite numerous attempts to get in touch with the tech, I could never get him to come back. Now I realize the purpose of the new-looking alligator clip lead that I found directly in front of the furnace - his bypass relay fell off, which is why we're having the problem again.



If it were just a malfunctioning of the safety switch, as he said, would only that piece need to be replaced?

ProfessorTim

Sometimes it's just a sensor. Replace it. Don't jumper it.

Hi Jared,

Yes, if that safety switch is bad and giving a false indication of one of the very serious conditions (blocked vent), then it should be the first thing replaced. If I could find that technician I would give him a good hard slap for leaving that jumper on because it circumvents one of the safety interlocks that are there to keep folks from dying of carbon monoxide poisoning. You should get it replaced as soon as possible. I can't tell you what to do but don't jumper it.



Best Regards,

Tim

Tim McElwain

I am Tim, not Professor Tim

I notice in the photo that the vent damper is directly above the draft hood if I am seeing the picture correctly. The blocked vent switch as the Professor stated is a safety switch to shut the system off in the event the equipment is not drafting and removing products of combustion. It has been my experience that simply moving the vent damper away from the draft hood and placing it closer to the chimney or vertical vent will solve the pre-mature shut down of the blocked vent switch (also called a spill switch)



I would not have the guy who jumped it out back as he is dangerous and needs his head examined for doing such a dangerous thing.



You probably have an intermittent pilot type (spark ignition) system so solving the vent damper/blocked vent issue should also mean the no pilot lighting will go away.

kcopp

One other thing....

On the picture of the vent damper it has a solid plug installed in the damper. I think the wrong plug was installed... that is supposed to be a small hole plug on the damper not a solid plug if it is a standing pilot.... might explain the thermal switch going off.

JaredG

Thank you

Everyone, thanks very much for your advice. Although it sounds like it was a very poor tech that was sent here, I'll assume for the moment that he was correct that the spill switch malfunctions and replace that. I have a functioning CO detector in the same room as the boiler and it hasn't gone off despite the boiler operating for some time with that bypass, so I'm hopeful this is the issue.



If it doesn't fix the problem, I'll move on to addressing these other potential causes.



Thank you again!

Jared

Bob Harper

switch doing its job

The spill switch is doing its job telling you there is a venting problem. Have a pro pull the pipe, inspect the chimney and correct any issues. That includes depressurization of the Combustion Appliance Zone. Police the house for open windows upstairs, open attic access etc. have the pro measure your CAZ and provide makeup air as needed to maintain a slightly positive CAZ WRT outdoors and the adjoing space.

Only once you have eliminated those causes would I even look at the equipment because that's usually where the problem lies. Never leave a safety control bypassed. If you can't run it without the jumper then that house is uninhabitale so move out until corrected. Get yourself a low level CO monitor or two.

Tim McElwain

Jared G do not leave this system running with

this problem existing, it is not a matter of the device doing its job, it is warning you that you have a problem which could "KILL" you and your family. Bob Harper gave you the things to address, get a real pro to check out your system.