condensate problem in school

soak123

I work in the maintenance dept of a school system.One of the high schools has 2 cleaverbrook 350 hp firetube boilers and along with it a boiler feed tank to recieve the condensate.The feed tank has 3 inlets to it, 1 main,1 smaller main from lockroom and aux gym, and 1 from a condensate tank(pumped) 400-500 feet away that does upper industrial art wing.The problem is that at nite the vent at boiler feed tank is ripping steam or flash steam into the boiler room.any ideas?

soak123

BTW

the steam traps have all been rebuilt 2 -3 years ago

Pumpguy

The only way...

 steam can get into your boiler feed tank is past a bad trap out in the system, or possibly past a bad check valve on a boiler feed pump. 



Typically, boiler feed pumps discharge into the boiler below the water line, so that's not very likely. 



I suppose it's possible there's a steam leak across an equalizer line between the steam header and return line.  Again, not very likely because that leak would cause steam in the return line all the time. 



Now, if your steam header pressure is high enough to allow the condensate to flash back into steam on the return side, that's also a possibility, but not very likely unless your operating at excessively high steam pressure. 



Traps don't last forever.  Something to keep in mind.



Hope this helps.

JStar

Steam

Are you using steam to make hot water through a heat exchanger?

What pressure are you operating at?

EBEBRATT-Ed

Traps

Most likely bad traps. If your steam pressure is high you could get flash steam back at the boiler feed tank.

Either way the high condensate temperature will kill your feed pumps and pump seals if not fixed