Spill switch tripping

[nonstop10977]

Hi all, I’m servicing an apartment building with 7 small Penco boilers in the boiler room. They have a spill switch on bottom right outside the burners, where you typically find a roll-out switch. 2 of them keep tripping. I replaced the switch, didn’t help. The chimney is sized right, they seem to be burning ok, and the other five boilers are fine. Any suggestions?

 

[Twowaxhack]

Might have a source of negative air pressure. Like a big fan coming on intermittently.

Or not enough makeup air in the room

 

[nonstop10977]

Thanks, that would be my first guess. I’m just confused about the fact that it’s always the same 2 boilers.

 

[Twowaxhack]

Thanks, that would be my first guess. I’m just confused about the fact that it’s always the same 2 boilers.

I’d have to be there to give you any real useful advice.

Maybe try swapping the spill switches to a different boiler rather than replacing them. See if the problem follows the switch.

Might be the control valves with a fault ?

Are the vents different in any way on the two that are tripping ? Location innthe room ?

Moon phase ?