is there an overfill cutoff solution when switch sticks in 157S control?

Malcolm

I have a Boilersmith 30 hp steam heating boiler and occasionally the switch or switches stick in the 157S condensate return pump controller. Yes I am ordering new switches but it seems odd there is no protection against this failure - it causes flooding downstream (where there is not supposed to be a stream). I have a water detector sensor in the top of the remote condensate return tank and it has worked well but that tank is not a boiler. Is there a standard practice solution out there?

Jamie Hall

There's another thread on this -- look for high water cutoff. There doesn't seem to be a standard solution, though...

You are probably already aware that condensate return tanks and pumps -- as opposed to boiler feed tanks and pumps -- are prone to overfill problems, since even if the switches don't stick the condensate float and pump have no way of knowing how much water is already in the boiler -- and will merrily feed whatever is in the tank, regardless of the boiler water level. Since boiler feed tanks and pumps are controlled by the boiler water level, they won't do that (although they have been known to overflow onto the floor..).

EBEBRATT-Ed

If you have a boiler equalizer or header drip you could install a "boiler overflow trap" You cut a tee in the equalizer just below the top gage glass connection. On the branch of the tee a gate or ball valve, strainer and stem trap. I would use a 1" trap. Pipe the trap into the condensate or boiler feed tank.

The 150 pump control switches can be troublesome. The older mercury switches seldom failed but I and others I know have had some issues with the new ones. Always the same issue overfilling the boiler, have taken the controls apart, cleaned, cleaned pipe connections etc they work for a week or so and flood etc saga continues

Wondering if pump motor amps has something to do with it? Maybe switch can't "let go" Maybe go pilot duty using a relay

Jamie Hall

Hadn't thought of the boiler overflow trap idea, @EBEBRATT-Ed . I always learn something on here... brilliant.

EBEBRATT-Ed

@Jamie Hall
I must say brilliant has never been used to describe one of my ideas LOL. See them on a lot of commercial jobs. More often with pumped returns/multiple boilers. Good cheap insurance