I have a Burnham Boiler and had the luxury of disecting a bad aquastat.
There is no mercury bulb in it. The probe which sits in the boiler tank is
responsible for temp feedback. You have a low limit and a high limit. The
aquastat I disected was faulty because of the high limit switch. There are
some springs incorporated in the switch and it had popped off.
Basically, if it keeps shutting off at 180 even when set higher, you too
have a problem with the high limit switch or circuitry attached to it.
I'm curious though, why would you need it set higher than 180?
"Tom" wrote in message
oups.com...
When contractor installed, the boiler was spec'd around 25% over my
needs to accomodate a home expansion we plan. So no, the boiler should
be sized ok. The "not working" simply means: I set the aquastat to
ANYTHING above 180deg and the gas is turned off when the boiler temp
guage hits 180deg. I set the aquastat to 220 (max it would go) and the
boiler shuts off at 180deg. The contractor used remote temp guage to
confirm boiler guage is accurate. I am not sure how to tell of pressure
of gas, but my fireplace (40k btu) worked fine when I tested it last
week. Since they share the same gas source, this confirms I have ample
supply of gas. For past 11 years, with old boiler, I ran fireplace and
boiler, stove, hw heater, dryer etc. all together without ever having
this problem. It would really help me sleep to understand why the
aquastat will not function correctly, but moreso- why would Burnham
authorize a letter indicating the jury-rig is an approved setup?

Still looking..... Thanx, Tom.