Steam or HWLoop?

vaporvac

So while I'm waiting to finish the ceiling and concrete base for my boiler install, I've been thinking about the plan to heat a currently well insulated, but large space in order to use it year-round. I had originally planned to do a HW loop, but the thread on  "best system for large sporadically used spaces" got me thinking that maybe I don't want hot water due to the risk of freezing pipes coupled with a long heat-up time. I was so impressed with how quickly the steam brought my house up to temp after a deep set-back (basically 50deg when I couldn't get the system running). It was so fast and I have 1466 edr to heat up! Plus, it FELT really warm as it heated up which I never get from HW..



This is only a space that would be used a few hours max most days, so I'd hate to heat it all the time. It's also below-grade, although the ceilings are about the same height (maybe a little lower) than the mains. Can I use the steam to heat this space? Would I have to use ceiling rads as that could prove problematic. Can steam ever go downhill? I know that's a really stupid question, but I'm now thinking steam would be better for this space.

I need to read about the mimi-tube system, but my understanding is it's not compatible as an add-on and I suppose the laws of physics still apply!

There is a gas line, currently capped off,to this room, if that helps. I think it used to be heated by some sort of gas/wood stove. Any suggestions or questions welcome.

jumper

if you already have steam

if you already have steam use it. What's wrong with ceiling rads ? Steam can go downhill but water can't go uphill. So if condensate is lower than boiler you need some way to lift condensate.

vaporvac

Too Much weight?

Thanks for the reply, Jumper! I'd like to avoid ceiling rads as I feel they may be too much weight for the old concrete ceilings, although i could use the lighter weight modern ones. Mainly, I hate to drill into the old concrete and cause any fracturing. They are supporting 2ft of soil up above. Could I use the actual piping as radiators and run it up against the ceiing, but then what about the condensate? That might not work. Maybe I could put a rad high on the wall supported from beneath.

Would a condensate pump solve the issue of bringing the condensate uphill?

Jamie Hall

How about using fin tube?

Set it high enough so that it is above the water line when steaming, and run it around as much of the wall as you need -- surely the wall can support the weight of the pipe hangars for that.  You could run two or three times around, for that matter, if need be.  I probably would divide it into sections, with parallel feeds, so it would heat evenly, but even that isn't that hard to do.



Run the ends into a wet return to collect the condensate and you won't even need traps, but you would need a vent on each section where it goes into the wet return, of course.

jumper

good point

Jamie makes a good point. You can still use one pipe system in basement even if rest of house is two pipe.

vaporvac

Vacuum and 1-pipe?

This is getting interesting. Does one-pipe affect the vacuum in the rest of the system. I hadn't considered fin-tube so I'll have to do a little research, although I SHOULD be concentrating on the near-boiler piping.

Jamie Hall

Shouldn't

affect it... it would depend, though, on how you piped it and vented it (what kind of vents you used).  You would need to use vents which held closed under vacuum...



You could run a line instead of individual vents to your dry return, which -- I presume -- is where your vents are now?  That would have to be trapped, of course, or orificed...



Gets a little complicated, but if you think it through there is no reason it shouldn't work.

vaporvac

This could work.

This could work, Jamie. I only have one vent on my system...the Trane vaporvaccum vent with the mercury pot. I think I could use the fintube if they're not too heavy. I'll get back with this soon...If I don't get the boilers installed I won't have to worry about heat in the pool room!



Have you looked at the proposed piping diagram? We'll be drawing another, but wanted a few more comments concerning the current drawing. Thank you. Colleen