Which Vaporstat to get?

Steve_175

I need to get a vaporstat for one of my boilers. It currently has a Honeywell PA404A1033  but it does not seem to do anything. The other boiler has an older Honeywell with a mercury switch but no model number anywhere on it.

I called Honeywell and sent them a picture of the one I have. They thought it was a model L404F1060/U. But that model is rated for 2-15 psi. 

If my knowledge of residential steam boilers is correct, I should get a vaporstat that operates in oz’s like the Honeywell L408J1025. Which one should I get?

46823_PROD_FILE.pdf

Here is the old vaporstat and it works well.

The boiler I want to put the new vaporstat on

EdTheHeaterMan

Is there a problem with the way the system operates?

If it is heating properly with no banging or surging or water coming from the air vent, then don't fix what ain't broke.

Of course that 5 PSI pressure difference between those two tappings in the front plate is kind of interesting.  I did not know that the internal pressure of such a small residential boiler could fluctuate so much in that short distance.