Basement Radiators....Free Lunch?

AdmiralYoda

Since it isn't heating season I'm having crazy ideas of modifying my system again. I have a 40 year old boiler that is in great shape and still going strong, but it is 40% oversized.

I have a field stone foundation and the basement tends to run a little chilly and I was thinking of putting a wall mounted radiator in the basement above the water line. Since the boiler is already running and has more then enough capacity.....will I essentially be heating this radiator for free?

Adding some additional EDR should reduce cycling on pressure as well. Maybe.

Thoughts? Oh, btw....it is a single pipe counterflow system.

Jamie Hall

Well, it won't be free -- the steam the radiator condenses has to come from somewhere. But it will work just fine.

As you note, the bottom of the radiator must be above the boiler water line -- plus the pressure factor (28 inches per psi). You may have to mount it horizontally from the ceiling, depending on your heights. That's not a problem -- just hang it securely (!) and make sure it is tilted enough to drain. You may not be able to get the slopes you need to make that one counterflow. No problem. Inlet as usual, then from the other end take a condensate line (doesn't have to be big -- 3/4 inch copper will be ample) and run it below the water line back to the boiler. Air vent on the radiator, of course.

AdmiralYoda

Thank you @Jamie Hall! I do have a couple follow up questions. First, the perfect place for a wall hung radiator to go would be on the opposite side of the wall the boiler is up against. There is a main on the ceiling right there and the return will only have to go 4ft back to the boiler.

Questions:
1. Will steam move down in a pipe? It would be convenient to have the inlet for the radiator a foot or two below the main. Would I just have to configure it so that the condensate returning down the main won't enter the new runout?
2. Since this radiator would essentially be piped as two-pipe, will I need a vent on the condensate return to the boiler? I'm picturing the steam entering the condensate return....but I'm not familiar with two pipe.

EDIT....I'll add another twist to the question.
What about adding some sort of hydronic panel to use some of the hot condensate return? Say a 6ft' section of 12" hydronic panel heater below the waterline? The condensate drip legs would feed it and the output would go back to the Hartford loop. Would this do any good?

ethicalpaul

Steam will move any direction in a pipe. Witness the drop header.

EdTheHeaterMan

Have you considered a water filled radiator set below the water line? Add a circulator pump to run. on a basement thermostat.

AdmiralYoda

@EdTheHeaterMan I have, but I'm trying to keep it simple-ish. I was thinking of just installing the radiator high enough so that the bottom is 28" per psi above the water line of the boiler. I run at about 12 oz so maybe 24" should be fine.

I'm still not sure if I'd need a vent on the return from the radiator, I have one-pipe counterflow and this radiator would be installed as a two-pipe. (Unless I install it on the ceiling, which I'd rather not do).

The location I am thinking is 4ft from the boiler so it shouldn't be too difficult. But I could be way off, a hot water loop with some cast iron baseboard might be the way to go.

Jamie Hall

Your best and simples bet, @AdmiralYoda , is to run the outlet down below the water line and back to the boiler, and yes you'd need an air vent on it if you did that. Pipe the outlet straight out with a short nipple and a T, the vent goes up and the condensate return goes down. As I said before, 3/4 inch copper would be ample -- for that matter, 1/2 inch would do.

The idea of radiation on the condensate return is always attractive -- free heat! But precious little of it. Consider that even a fairly typical residential boiler -- say 100K or so -- will only produce a pound or two of condensate per minute. Not much heat there.

The advantage of the hot water loop is control. The disadvantage is complexity.

mattmia2

The vent just has to let the air out of the radiator so it can be on the radiator more or less opposite the inlet or on the condensate return, right?

Jamie Hall

mattmia2 said:

The vent just has to let the air out of the radiator so it can be on the radiator more or less opposite the inlet or on the condensate return, right?

Yup. Whatever works...

AdmiralYoda

Jamie Hall said:

mattmia2 said:

The vent just has to let the air out of the radiator so it can be on the radiator more or less opposite the inlet or on the condensate return, right?

Yup. Whatever works...

Great! So nothing too fancy then. Just a regular old Maid O' Mist or Gorton radiator vent like I have on all my radiators upstairs? Or something a little more robust?

Oh, and do I need a steam trap or something on the inlet side of the radiator? My system is single pipe counterflow, the way this radiator would be installed is technically two pipe, right?

mattmia2

AdmiralYoda said:

Oh, and do I need a steam trap or something on the inlet side of the radiator? My system is single pipe counterflow, the way this radiator would be installed is technically two pipe, right?

That is why you connect the return below the water line, it uses a water seal instead of a steam trap.

Anything above the water line in a 1 pipe system could have steam in it so an attempt to use a steam trap could result in the trap being closed by steam at the outlet

AdmiralYoda

Got it, thanks again everyone!