conversion

joe amadio

I have a customer that owns an old funeral home.. Currently they heat the place with oil fired steam. The current system is a one pipe steam system with wet returns.It is two zones. 1st floor, 2nd floor. This was accomplished by using two zone valves. ( See pictures).The 1st floor zone consists of one steam supply header feeding a blower coil which heats the entire 1st floor through a duct system. The coil is lower than the height of the steam supply main. It is being fed downward off the main. I think utilizing the hot condensate return water. The return from this coil then comes back to a Sarco steam trap then into a condensate pump to be sent back to the boiler. (See pictures). The 2nd floor zone has one supply header leaving the boiler and branching off to feed each radiator. There are two returns coming back from the 2nd floor. Both are trapped using the same Sarco traps and both then enter the return pump to be sent back to the boiler. I would like to remove this boiler and install 2 gas boilers in its place. One will be steam for the 2nd floor only. Do the traps and condensate pump need to be reused? I cant see any reason why the 2 second floor returns can't be piped directly into the boiler. The only thing I can think of is that the current boiler is a replacement for one that held a lot more water. and that the replacement being smaller was boiling off the water on a call for heat. Then over filling via the auto feeder, The 2nd boiler I would like to run as hot water. Can I simply just feed the existing blower coil using forced hot water? Do I need to continue to feed the blower with steam? If so can I still split the 2 floors using 2 boilers and eliminate the condensate pump altogether? Can I run the coil without the pump and just the second floor through it? Or do I need 2 pumps one for each boiler?

jumper

yes

Coils I've seen can be piped for steam or hw. Zone valves make steam less simple. I'd try to eliminate pumps. OTOH if the condensate pump is really pumping hot water through that duct coil it sounds like a brilliant design.

Steamhead

Check your heat loss

for the first floor. Just like a radiator, a steam coil will only emit about 2/3 as much heat on hot-water as it will on steam. And if it needs a trap and is discharging into a condensate tank, it's definitely running on steam.



What is your total radiation load? You may be able to use a boiler with lo-hi-lo firing to accommodate the load variations when different zone valves open and close.