Removing radiators

rcrit

I have a 1920 3-story home with an undersized one-pipe boiler and no A/C. I'm investigating getting a high velocity air conditioning system installed (the one with the 2 inch tubes instead of ducts) to cool the first and second floors. For the third floor where I have a home office and lots of computers they want to install a Mr Slim wall-mounted unit. The is also a heat pump.



The first floor cooling will consist of a 10" trunk around the perimeter of my 3rd floor that will feed the tubes for the first and second floors. This would run right through the two radiators I have so they would need to be removed. Not a huge loss since the heat pump would probably be fine to heat my office with the amount of solar radiation and computers I have.



This is a long way to ask: if I go ahead with this and have them run the trunk line and remove the radiators, how far should I take this? Each radiator is fed from a riser hooked to a different radiator on the 2nd floor. Would I want to remove the riser completely and cap it off at the 2nd floor radiator or cap it off in the 3rd floor crawl space? Would I want to hold onto this pipe for future repairs? If I do end up removing the radiators I'll definitely get a non-knucklehead out to do the work separately to ensure that it's done right.

Nick_C

My thoghts

I would cap the takeoff as close to the riser/main as possible.  Heating pipe is just a waste.  Plus you never know when a perfectly fine pipe will spring a leak.  Cap it as close to source as possible.  I'd probably leave pipe that's buried in a wall well enough alone, though.  It can serve as a nice conduit for things like fiber and ethernet cable.

Steamhead

I wouldn't do that

all you need to do is elbow your pipes over and relocate the radiators. Despite having some sun and computers, you'll never be happy with a heat pump.



This would be pretty easy for someone who has pipe threading equipment. And I know you know who does......... ;-)

rcrit

I wouldn't do that

LOL, true enough.



At this point I'm wondering if I need any direct heat in here at all. It's 83 right now, 19 outside and I have a window open. I shut off the radiator valve last week as an experiment and it's fine so far. Probably brings my EDR closer in line too.

nicholas bonham-carter

turning off 3rd floor rads

as a temporary turn off, you can turn the air vent upside down to prevent air from getting out. this stops the steam from rising.

if the top floor is too hot with the valve off, maybe your system could use some balancing, or TRV's.

i wonder if those high velocity ducts are noisy. a mini-split would probably be quieter, and involve less disruption.--nbc 

rcrit

turning off 3rd floor rads

Well, yes overheating is another part of the story. My second and third floors are quite warm while the first is cool (and this may be partly due to poor insulation, leaks, etc). This is most pronounced when the boiler runs very frequently. What I see on mild days is some of the second floor radiators don't get any steam at all, even with a Hoffman 1A variable vent with the set screw removed (aka most venting possible).



I have two mains, one shorter than the other. The shorter main is vented at the end with a Hoffman #75. The longer main is vented about half-way down with a Gorton #2. Both vents are above returns.



In my office I had the vent set to the slowest setting and still it heated all the way across. I shut off the valve and now it's nice and cool.



A TRV for my 1-pipe system might be something like this, right?

http://www.pexsupply.com/Danfoss-013G0140-Thermostatic-Rad-Valve-w-Vac-Breaker-1-Pipe-Steam-5551000-p



In this case the V in TRV is a vent, not a valve? That would make installing it a lot easier for me too.

nicholas bonham-carter

out of balance system

definitely increase the main venting, and get the system balanced, so that steam arrives at all radiators at the same time. check that with the surface temperature of the radiator, and not the room temperature. this will need to be done to help the trv's do their job more easily. those from pex are fine i am sure.

check your thermostat for anticipation, or correct setup for steam=1 cph..--nbc