Pressure in steam condensate tank.

Garret_9

What am I missing? The boilers run between 8 and 12 psi steam pressure. I have .5 to 2.5 psi pressure in a Skidmore condensate tank that is vented to the roof. Flash steam is pouring out the vent. All 50 traps have been checked by a trap survey company. A couple of traps are suspected of leaking by. They have been isolated. The 3" vent is run a long distance and is not pitched correctly before going through the roof. Is the hot condensate flashing to steam causing pressure in the return lines and condensate tank or is it the vent line pitch causing the problem or could there be more traps leaking that the trap survey company missed? Please help!

Michael Wilson

Does dropping the pressure help?

ed wallace

pressure n condensate tank

you need to turn down the settings on the pressuretrol its way to high drop it down to 2 psi cut out .5 cut in that will lower the pressure in the condensate tank it takes 5 psi to heat the empire state building

Steamhead (in transit)

Ed's right

it's flash steam for sure. Is there a large trap in the return line approaching the Skidmore? If so, get rid of it. It kills the return flow of both condensate and air.

Here's a thread that describes how we dealt with a similar situation:

http://forums.invision.net/Thread.cfm?CFApp=2&Thread_ID=59088&mc=13

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Mark_124

Condensate pressure

Thanks everyone.
I have to be carefull not to allow the building air handlers trip off on freeze when I lower the boiler steam presure setpoint. If the boiler shuts off at 8 psi and cuts in at 4 psi it takes time for the boiler to get up to high fire and by that time the pressure could be 2 psi and the air handlers would have tripped out on freeze.

The boilers are 2 500HP Cleaver Brooks CBE

We have 4 Air Handler at 35000 CFM that are 100% OA and 2 that have economizers.

I was thinking of adding a test valve on the unused port on an F & T trap to check the outlet pressure. If I have 2 psi in the condensate return lines at the air handlers in the penthouse could I add 1" tees in the return lines and pipe a 10'line up to the ceiling in the penthouse as an open vent in addition to the 3" vent at the condensate tank that goes to the roof?

Mark_124

I Just discovered what I think is a major factor in the pressurized return line. I checked the pressure before the traps at the strainers. It is 11 freakin pounds!!

My understanding is that an F&T trap needs only 2 psi differential to work. I wonder what the pressure is leaving the trap.

I hope I can get the 2" pipe plug out on the alternate return port on the trap so I can read the pressure there.