Use the overhead Main in a basement, instead of a radiator?

rhodie_

Hi Guys. I have a 1/2 finished basement with a single pipe system and 2.5" mains (i believe). We used to have a baseboard loop running off the old boiler to heat the finished part of the basement, but I don't really want any water running through there with kids who are prone to destroying stuff, so the loop is turned off, capped, and the baseboard pipes in that part of the room were removed. The main runs the full length of the closed off room (25' or so) in a 25'x14' room. When that room was remodeled, the pipes were insulated and a box was built around them to conceal them. The room gets cold, so we use a space heater, but I was thinking to cut out the bottom of the box, remove the insulation from the pipes, put reflective insulation inside the box, above the pipes, and then put a screen inside the box, to cover the part that I cut out. Basically, it would create an overhead radiator, using the mains. I'd have to adjust the vents on all the radiators for the newly-lost heat, I suppose, but my boiler puts out plenty of steam already, so I think it would be fine. The whole room is insulated, so I really only need a few degrees every time the boiler runs, to keep it relatively warm down there, I think, My question though, is, can you have an overhead radiator? I know heat rises, but will opening up that box and putting insulation ABOVE the pipes be enough to reflect some heat back into the room, or will it all just hover at the ceiling and be a waste? Obviously, having a radiator or baseboard system on the floor would be preferable, but not in my case.

ChrisJ

I've got a feeling you're going to get a lot of mixed feelings on this.

My opinion is if you can find a way to use the condensate (dry return, wet return) to heat the space it'll be a lot more beneficial but opening up and exposing the main could work as long as the system will still heat the rest of the house properly.

Overhead will work, but as you said not as good as something down low. Same way as many central air systems work with the vents in the floor or down low on the walls, they work, just not great.

If you can come up with a way to promote air flow through the box it would be better. Such as a wide slot all across the bottom, maybe 4" wide or so, and then a 1" slot all the way across on each side near the ceiling. It would create a natural draft through the enclosure. 100% guessing on this one, but it works in my head.

KC_Jones

The big question really is what are your expectations? A 2" pipe (2 3/8" OD) has an EDR of .88 per foot which translates into 211 BTU's per foot. So with 25' of main you will get 5275 BTU's out of that pipe theoretically. The other problem is it would be centralized around that pipe not really spread out around the room. If your expectations are that it would be anything like the hot water loop you disconnected or the space heater you are using I don't think it will get you there. As Chris said there will probably be many opinions on this. Another possible option could be a ceiling radiator hooked into the steam system....a pro would know more about that.

vaporvac

How long is the main we're talking about?

rhodie_

Thanks guys. I think there's about 20 feet of main that's concealed right now. On the other side of the basement is the boiler room, and it's closed off with a door. When we first bought the house, there was very little insulation on the piping in there. Most of the main surfaces were covered with 1/2" home depot tube wraps, none of the risers, nor the connections. With the door open, that was enough to actually heat the entire basement, but was wasteful. Plus, I like that door closed to keep the kids out of the boiler area. I have since insulated everything quite well, which is why it's too cold down there. It gets down to about 62 degrees at the lowest, in the basement, even with the door closed, so I really only need about 8 degrees. Remember, that room is insulated. I like the idea of side vents and bottom vents, but if I'm going to cut that much out, I might as well just remove the whole box and go with exposed pipe. It won't be pretty though. I probably should just put the baseboard loop back in there. Certainly more efficient, but the idea of 6+ gallons of water leaking onto the floor after one swift kick from my kids has me too worried. Space heater is fine, but it's dry and a bit loud. I suppose I could just get an oil radiator down there, too, but they're super stinky. Anyhow, you guys are great. Thank you for the thoughts, and the BTU calculation!

SWEI

I would probably look at piping a radiator or a length of commercial fin-tube in series with the condensate line. http://www.slantfin.com/index.php/products/baseboard-commercial/fin-tube-bare-elements are available in steel.

Keep the main insulated if you can.

ChrisJ

rhodie_ said:

Thanks guys. I think there's about 20 feet of main that's concealed right now. On the other side of the basement is the boiler room, and it's closed off with a door. When we first bought the house, there was very little insulation on the piping in there. Most of the main surfaces were covered with 1/2" home depot tube wraps, none of the risers, nor the connections. With the door open, that was enough to actually heat the entire basement, but was wasteful. Plus, I like that door closed to keep the kids out of the boiler area. I have since insulated everything quite well, which is why it's too cold down there. It gets down to about 62 degrees at the lowest, in the basement, even with the door closed, so I really only need about 8 degrees. Remember, that room is insulated. I like the idea of side vents and bottom vents, but if I'm going to cut that much out, I might as well just remove the whole box and go with exposed pipe. It won't be pretty though. I probably should just put the baseboard loop back in there. Certainly more efficient, but the idea of 6+ gallons of water leaking onto the floor after one swift kick from my kids has me too worried. Space heater is fine, but it's dry and a bit loud. I suppose I could just get an oil radiator down there, too, but they're super stinky. Anyhow, you guys are great. Thank you for the thoughts, and the BTU calculation!

I think you missed my point, though.
The point of the side and bottom vents was to create a convector, of sorts. The draft through the enclosure should increase output vs just a bare pipe.

I'd look into cast iron radiation to replace the baseboard, I think you'll find it more effective and a good swift kick will only hurt the person with the foot.

Jamie Hall

The biggest problem -- other than rather uneven distribution of heat in the space -- that I can see is that on startup you will get a LOT of condensate from that pipe. You should definetly slope it so it is parallel flow, and drip the far end into a wet return or at the very least put in a trap going to a dry return, which will have to be a foot or so lower. Could be a bit difficult? Otherwise, you will almost certainly get some hammer from it.

I would seriously consider a wall or ceiling hung radiator, if you don't like the hot water loop (which is the best bet, by the way!). So long as the outlet from the radiator is above the boiler water line plus you 28 inches or so, it will get only steam. The outlet through a trap, as usual, and then T into a vertical -- top goes to your dry return, bottom to a wet return.

Dave0176

Or you can pick up some new cast iron radiators made by Burnham and run you hot water loop through them.

RobG

Dave0176 said:

Or you can pick up some new cast iron radiators made by Burnham and run you hot water loop through them.

Simple and no demolition involved (except what it would take to run the piping).

ChrisJ

RobG said:

Dave0176 said:

Or you can pick up some new cast iron radiators made by Burnham and run you hot water loop through them.

Simple and no demolition involved (except what it would take to run the piping).

There may be some demolition of sorts if someone kicks one.