STEAM COMING OUT OF A CONDENSATE PUMP

NORM53

WE HAVE A CHURCH WITH 2 STEAM BOILERS THAT ARE PIPED TOGETHER.  THE CHURCH IS A 1 PIPE STEAM SYSTEM.  ONE OF THE BOILERS DEVELOPED A LEAK AND WE REPLACED THE BOILER.  SINCE THE BOILERS NOW HAVE DIFFERANT WATER LEVELS WE INSTALLED A PUMP CONTROL ON EACH BOILER.  ON A CALL FOR MAKE UP WATER A SOLONOID VALVE AND A CONDENSATE PUMP ARE ENERGIZED AT THE SAME TIME.  WITH 1 BOILER OPERATING EVERYTHING WORKS PROPERLY.  WHEN THE SECOND BOILER COMES ON RUNS FOR A WHILE STEAM STARTS TO POUR OUT OF THE VENT OF THE CONDENSATE PUMP.  WE ADDED A P TRAP TO THE INLET OF THE CONDENSATE PUMP AND THIS HELPS SOME.  WHEN THE STEAM IS COMING OUT OF THE CONDENSATE PUMP WE HAVE .5 LB OF PRESSURE ON THE GUAGE.  ANY IDEAS WHAT WE CAN DO TO ELIMINATE STEAM COMING OUT OF THE VENT ON THE CONDENSATE PUMP?

Dave in QCA

pictures please

It sounds like there is a piping error.  Could you please take pictures of the boiler, the piping and especially the returns where they  connect to the tank. 

Pumpguy

What are

the steam pressures when one boiler is running vs both boilers?  I would think if the steam pressure is the same with one or both boilers running, the system conditions would also be the same. 



Are there any steam traps in this system?  With both boilers running, you would be sending more steam out into the system, and this combined with a leaking trap could cause this problem. 



Sorry, I don't know too much about one pipe systems, but this site is slowly changing that.

As Dave says, pictures or sketch of the piping arrangement would give us a better idea of what's going on.

jumper

if you resolve this issue

if you resolve this issue please post how. Multiple boilers are complicated even when water levels are nominally equal. Who replaced the boiler ?

Jamie Hall

Oh dear...

that difference in water level spells nothing but trouble.  And is one of the commoner and more subtle errors in installing new boilers.



The steam coming out of your condensate pump from the new boiler indicates that somewhere in your system -- and it could be way out at the far end of the building -- what should be a water seal isn't any more (the problem could also be right at the new boiler, for that matter -- or the old one!) and steam is passing from the main to a return, and thence into the condensate tank.



Review ALL of the piping in the building, and look for a place -- or places -- where the new water level is below what should be a water seal from the steam mains to the returns.



The fix may be simple.  It may not.  It may involve changing the boiler installation to what it should have been, with the water level in the new boiler the same as it was in the old boiler, give or take no more than an inch. 

JStar

Steam

And that brand new trap at the pump inlet is both trashed and unnecessary right now. Take it out.

ttekushan_3

if I'm understanding this correctly,

you have one pump attached to a vented return tank (condensate receiver) of some sort. The pump on the vented tank is operated on a call for water from one or both boilers and the solenoid valve chooses which boiler gets the water.



If this correct, my guess is that the tank is sitting on the floor with its water line considerably below that of the original installation's water line, originally being at the prevailing water line of the original boilers. I think the return was originally "wet" with the return well below the boiler's water lines (fully immersed in water) and kept that way by being directly attached to boilers and subsequently held back by the steam pressure pushing down on the boilers' water line. It seems that now the return goes "dry" as soon as there's enough pressure in the system because the vented tank has broken the line of communication from the boilers backward into the return system.



Long and short of it is that I think you need a false water line. Instead of a P trap, you need a tall upside down version of a P trap with a thermostatic float type air vent on top. There may be something on this subject in the "Library" of this site, but I know for sure that it is covered in Dan Holohan's "The Lost Art of Steam Heating" available here in the shopping section. There it will explain what has gone wrong in your system and how a false water line brings the water level in the returns back to where they should be, keeping the steam out of the return system.

Paul48

Either

There's no F&T trap, or it has failed.

Greg S

Flash option

Norm,

This used to happen dramatically on my system when the pressure was too high. Condensate under pressure is above 212 degrees. Condensate tanks have open vents and are at atmospheric pressure. When condensate goes through a steam trap as water, it immediatly turns to steam with a pressure drop. Lowering the pressure through better venting combined with lowering the pressure limit on the furnace may solve the problem and make the system run more efficiently.  If the venting is fine, just lowering the furnace pressure is an easy starting point without engaging the complexities of two furnaces.

I am not a pro.

Greg S

NORM53

FALSE WATER LINE

This makes a lot of sense.  I looked up the false water line and we created one.  this took care of the problem.  Thank you for your help.

Charlie from wmass

Thanks for the feed back Norm

Here on the wall we often never get that unless we show up in person. I saw your post today and started reading down and was about to suggest the false water line and then I saw your reply. Bet you look wicked smart to the church now. It is not about having all the answers most days. just about knowing how to find them.

Thanks again for letting us know.