I have a Teledyne Laars boiler
model number PW0400CN12KBASN, a
two stage unit. The gas valve is a Robertson Grayson 7000DER2HC, it
has a Honeywell S8600F electronic control and a Honeywell two stage
temperature controller L6008G1009 (Laars part number RE0093200).
The problem is the boiler fires O.K. and the flames come up, but after
operating a little while the temperature increases the the point where
the high limit cuts the unit off. Then after it cools down the unit will
work again and go through the same cycle. If I turn the temp controller
down during this time the boiler will NOT cut off (even whenever it is turned all the way down to the stop).
I was thinking of replacing the temp controller and the immersion well
(I figured I would not be able to get the old bulb out).