Why do I have two pressuretrols?

MonasDad

Just now finished reading We Got Steam Heat (highly entertaining and riveting if you have current steam heat problems) so went straight downstairs to make sure my boiler pressure was low. One of the pressuretrols is where I thought it was (low) but as if looking at all this for the first time I see another pressuretrol! And the thing's over 10 PSI! What's going on here? Why are there two controls ... and if I had my boiler guy lower the pressure last year did it creep up or did he ignore one of the controls?



You can see in the photo that they are both connected to the same union, but what it doesn't show is that the power goes into the same junction box so I'm thinking they are both operational.

sreja

re: Why do I have two pressuretrols?

it's not uncommon to have one set quite high to trigger on high pressure and shutdown the boiler (and often require a manually reset button), in case something goes wrong with the main pressuretrol(s).



[some boilers also use multistage control where different pressuretrols trigger different amounts of gas.]

BobC

Safety

Srega is right about one being a backup to the other for safety. I see they are on separate pigtails also which is good because one blocked pigtail will not disable a very important safety.



Assuming one pressuretrol is set to trip at 2 PSI or less I would set the other to trip at 5 or 6 PSI, unless there is a specific reason for such a high setup on the backup.



Bob

JohnNY

Do you live in a multi family?

The setup you've got there is Code for a multi-family or mixed-use residence in NYC and other cities.

MonasDad

Thanks all

Thanks everyone, and yes I'm in NYC.



Should I trust this old honeywell? It looks like the older one is the one in control and the newer-looking one is just back up. Ive been thinking of just threading on a 0-3 psi gauge for some piece of mind.

BobC

that old honeywell

is probably better than the newer one beside it, just let keep doing it's job. If you add a 3PSI gauge just make sure it's on a pigtail, just put a T on one of your pigtails and use nipples and 90's to remount the pressuretrol and the new gauge. kill the circuit breaker before messing with the wires.



Bob

RJ_4

pressuretrol

Most cities require an operating control and a high limit on commercial boilers. In your picture the control on the left looks like a honeywell PA404 style control, This could be the oper. control.  The control upper right could be a high limit, it would have a L in the part no. like L407---    the older limit controls had a metal reset button on the top of the control.  Also Peerless used to use a 2 stg, control

JohnNY

Clearly,

the one on the right is the high limit control, with a manual reset button staring us right in the face protruding through the front cover.

RJ_4

clearly

You got a better resolution  I see a white reflection