Gas boiler not staying working
I have an old natural gas boiler that I need to keep going for one more winter.
I have replaced the thermopile but the unit continues to shut off and the pilot is out after a a couple of hours. I had the unit cleaned and inspected but I have doubts about the technician. While vacuuming the dust with a small handheld vacuum he never put a bag on it and my basement was then covered in dust and the air quality was “Visible”.
What do I have to do to keep it running? What pressure should the pipes be at-it seems to like to settle at 12psi even if i jack it up.
I keep the circulator pump running, will this keep the pipes from freezing even though they do not have hydronic antifreeze, like leaving a kitchen sink dripping?
How come the baseboard air release screws don’t vent air/water out even to the point of full screw removal?
Thanks for your wisdom.
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Replies
12psi is more than enough pressure for most full basement + 2 story buildings with a boiler in the basement, pressure measured in the basement. You may need to bump that to 15-18psi for a basement + 3 story.
System corrosion can block baseboard air bleeders if it's really cruddy. If there's a plug of ice in the plumbing that could block flow too.
Keeping the circulators going will keep the pipes from freezing in colder rooms as long as the average room temperatures throughout the system aren't substantially below freezing, as long as you have flow through all the baseboard. The pump itself would be adding some heat to the water. But if the average temperature in the house is in the low 20s it's probably not going to be enough.
Fluctuations in gas pressure from faulty pressure regulators can blow pilots out, but the valve assembly could also be sticky or failing. If the thermocouple isn't properly placed in the pilot flame it could be on the hairy edge, where an air draft could move the flame far enough off the sensor to cause it to turn off.
Without more information on the system and your local temperature conditions (interior and outdoors) it's a bit hard to say much more. It's not clear why the system would lose pressure after raising the pressure by adding more water. The system pressure would normally work within a range, it'll be lower when the boiler is stone-cold, higher when the system is hot. A properly sized expansion tank properly pre-charged to the design pressure for the system would moderate the swings in pressure with system temperature.
I'm no pro and know jack about boilers but we resurrected an medium efficiency boiler that everyone wanted to replace with a new power vent and a new pump and some air entry vents into the boiler room. Bonnet went from half light to full and it is still running great years later. Several tech/sales guys looked at it without suggesting air flow. So I wanted to throw out that if there is any chance you are starving the boiler for combustion air, you might look into ensuring adequate combustion air and exhaust air flow. Good luck.