why are my reliefs blowing?

Brad White_185

Part of your post says that you can run the pressure up to 15 psi without a problem while the lesser boiler blows at 10 psi, but you also say that both blow simultaneously. Not sure I am getting it all.

Do you have a photograph you can post showing the piping arrangement? Are the valves on the boilers themselves versus the out-feeds or header?

Is there a boiler feed unit and at what pressure is that running? Is it just hitting a certain pressure that triggers the release or is there another variable coincident to the lift-off?

Are the relief valves piped identically on their outlets? For example a drip-pan elbow or an induction cone? Or hard-piped where there might be a dip-seal? Fishing I know, seeking deltas.

Tom DesRoches

boiler safety releifs

Hello, I maintain, among others, 2 burnham 250hp fire tube boilers. There is a common steam header and they run on a lead/lag setup swapping once a week. These are low pressure boilers, and only during the coldest days do I need 10 to 12 psi. My problem is, one of the boilers will consistently blow off water from the safety relief valves if it calls for anything over 10psi. and only when it is running. I can run the other boiler as high as 15 psi. and the problem boiler will be fine even with the common header. I've had the pressuretrols, gauges, and controls inspected, and Ive replaced the relief valves(conbraco), and the problem persists. The strange thing is that both safeties let go simultaneously. I would greatly appreciate any sound advice.
Thanks, Tom