Sections of piping that don't allow easy drainage

dave123

Am sketching the piping for new rads. I was planning to use the bottom edges of the floor joists as the lowest plane in the distribution piping, but in this particular house, there is a steel I-beam running the length of the basement, upon which the joists rest at their midpoint. This means that the piping to the four rads on the other side of the I-beam will need to rise above the I-beam and come down again, because they will need to run flush to the bottom of the joists on that side of the I beam.

If the piping beyond the I-beam ever needs to be fully drained, the fluid there will be trapped by the rise/fall at the I-beam, and will not be drainable via the main drains near the boiler. Is this considered bad practice? Would the pros add separate drain valves for the trapped piping? Or just plan to let it all drain out into a floor bucket at the point of any needed work?

Also curious whether a rise/fall of 3-4 inches should get any sort or air vent?

Thanks.

Jamie Hall

This is hot water heat? If so, getting all the air out may be a bit of a hassle, but not that bad if you have adequate air vents on the radiators. As to draining, on the side which is otherwise hard to drain do yourself a big favour and instead of an elbow at the bottom of the return back down use a T and put a drain valve on a short nipple on the bottom of the cross (the other end goes up and the leg over).

EBEBRATT-Ed

If you want to follow best practice you would vent the high point and a drain at any low point,

But in a heating system it is common to have areas that won't drain completely.

I wouldn't give you a smack down for not doing it.

What you could do cheaply is rise up over the I beam and use a tee on top of the pipe that drops down. Put a bushing in the top of the tee and put a 1/8" coin vent in it to get the air our.

If you want a drain, put a tee on the pipe before it rises up to go over the I beam and use another coin vent for a drain or just use a pipe plug.

Cheaper than valves and it gives you access to drain and vent for low $$

If your running copper you can buy "baseboard tees" which look like elbows with a 1/8" female tapping for the coin vent

mattmia2

What about running it across to the joist bay that it needs to go in before you bring it up over the beam?

dave123

Thanks for the suggestions. The only other piping arrangement would be to run all four sets of pipes inside the joist bays and above the I-beam throughout their length, which would maintain the proper slope back to the boiler, but this would require 175 feet of 1/2 inch piping, as opposed to the 75 feet of 3/4 piping I was going to use to run a reverse-return loop over the I-beam and back. But then that requires extra measures for drainage and venting.

Which option makes more sense?

EBEBRATT-Ed

I would run it in 3/4" just put a coin vent on a baseboard tee as previously mentioned to vent. Don't worry about draining. Is this piping going to be exposed in the basement or a hard ceiling or a drop in ceiling??

Hot water heating you can run up, down sideways...any way you want.

Most don't worry about draining. If it's easy to make draining provisions ...fine if not don't worry about it.

as far as venting goes if the flow has enough velocity the air will be carried back to the boiler and removed at the air separator. a short rise up and down (a foot or so) probably a non issue especially with a small pipe like 3/4". But the only reason not to put a coin vent on it would be if it's behind a hard ceiling with no access and you can always put a access panel in the ceiling.

I know your trying to do it right but you may be over thinking it

dave123

EBEBRATT-Ed said:

I would run it in 3/4" just put a coin vent on a baseboard tee as previously mentioned to vent. Don't worry about draining. Is this piping going to be exposed in the basement or a hard ceiling or a drop in ceiling??

Hot water heating you can run up, down sideways...any way you want.

Most don't worry about draining. If it's easy to make draining provisions ...fine if not don't worry about it.

as far as venting goes if the flow has enough velocity the air will be carried back to the boiler and removed at the air separator. a short rise up and down (a foot or so) probably a non issue especially with a small pipe like 3/4". But the only reason not to put a coin vent on it would be if it's behind a hard ceiling with no access and you can always put a access panel in the ceiling.

I know your trying to do it right but you may be over thinking it

Thanks. I've done a lot of HVAC and plumbing in my life but I'm not a professional. But I hate to think of anyone seeing my work down the road and thinking "Ugh, what moron did this."

This piping will all be through exposed basement ceiling though.

mattmia2

If it would make it a lot longer then the added fittings for draining make sense. If you set up the boiler as pumping away with the expansion tank in the right place and a good microbubble scrubber air eliminator and valves to be able to purge each section then you shouldn't need a vet on the loop, just a drain.