Piping Multiple LP steam boileers

steve_25

We are replacing two 24 year old LP steam boilers in an old church. I have

read that IECC 2012 requires the boilers be isolated from each other (probably

with check valves) so the lag boiler is not soaking up heat from the lead boiler.



It seems like a good idea both to reduce heat loss from the idle boiler

and also because the church office is right above the boiler room and

they are often overheated by heat from 2 hot boilers coming up through

the floor.



I have not been able to find a specific isolation requirement in the code and wonder if it is really required??-



and I'd like to hear what the Pros think about the idea of boiler isolation with check valves?



Thanks for any input.

nicholas bonham-carter

Tag team boilers

The manufacturers instructions will have some specific instructions for piping two boilers together.

Are these serving different areas of the building? It would be important to keep the pressure as low (ounces), as possible, so as to prevent any flow the rough the returns into the inactive boiler. They could be staged on a vaporstat, with both firing at zero pressure, and then the lag cutting out at 4 ounces or so. Ample main venting is a must here at those low pressures.

I hope you have sized them correctly by the EDR of the radiation!--NBC

steve_25

Piping Multiple Boilers

The Mfg (Smith) has no info on multiple boilers in the installation manual.

 Since  both boilers connect to a common header the idle boiler

 gets steam from that header. The isolation check valve would

eliminate that.

JStar

Boilers

Steam will want to go where the air can get out. An idle boiler has no way of letting air out. We don't find it to be that great of a concern. Plus, I've never seen a check valve on a steam supply.