steam keeps goin on and off

PFPH

I'm trying to fix a steam boiler I got a no heat call and I replaced the pigtail then the tsat.the heat keeps going on and off **** help please.

furnacefigher15

What is controlling burner?

What is shutting of the burner?

Pressure, Thermostat, Timer, Lwco?



How much does it cycle? Do you see it happen?



A lot of things can turn the boiler off.

nicholas bonham-carter

off and on

try putting a jumper on the terminals of the control, to simulate a call for heat, and see what part may be shutting down the burner. if it runs continuously, then the thermostat could be set incorrectly for steam.

if it is shutting off on pressure, then check the main vents.--nbc

Jamie Hall

keep in mind, too,

that you may have more than one pressure control and more than one LWCO.  You have to find out, as furnacefighter15 says, what is turning the burner off -- and then you have to find out why.



The thermostat, IMHO, is the least likely culprit.... at least, if the cycles are close together.