Church steam heating system

wsm232

I was brought into an old existing church which has steam heat and constantly overheats. I found that the 3 inch zone valve is blocked open as the motor does not work. I found that the main church building has a 6 inch zone valve which also does not operate. The 3 inch zone gets heat every time the main church calls. The main church 6 inch steam main heats a heat exchanger which then circulates hot water to the main church. My question is this. Can I just install a new 3 inch zone valve to regulate the heat to the small building and remove the old 6 inch valve that feeds the heat exchanger and leave the system like that. Or is the 6 inch zone valve needed so that the heat exchanger does not boil the water if the main church is not calling. I think the latter makes sense but the church does not have the monies to change the 6 inch valve and piping. Any suggestions out there.

Jamie Hall

A six inch valve

will cost most churches their annual budget -- and then some.  You really only need to replace the 3 inch, and I would wonder if you need to replace the whole valve, or just the actuator?  Worth checking.



Having steam to the heat exchanger all the time won't boil anything.  Remember that the boiling point of water increases with pressure, and presumably (I hope!) your hot water circulation in the main church is under at least some pressure.  The water will get up to 212 or thereabouts (you are running low pressure, aren't you, in the steam side?) but then it will just sit there -- and, in fact, the heat exchanger will stop condensing steam (well, almost stop...), and effectively completely remove that demand from the system (I presume there is a trap on the heat exchanger?).



So -- bottom line, you'll be just fine taking that 6" right out (or, for that matter, leave it in blocked open!) and putting a new valve and actuator, or just a new actuator, on the line to the little building.

Scott McGuire

reply

Thanks for your response. Makes sense to me. It is a low pressure boiler and there is a F/T trap on the heat exchanger. We will give it a try and see what happens.