Radiant Heat off a Steam Boiler

rhl

My friend is trying to add floor heat to his gut reno in lower manhattan. His complex has a steam boiler and one pipe feeds to various radiators.

How do you do this? He's spoken to a few plumbers and most have thrown there hands up.

We were guessing off of a return or supply pipe a heat exchanger to a hot water loop with expansion tank and standard trim?

There was some concern that the plate heat exchanger is not steam capable. I have no idea if this is true.

JUGHNE

You use the water in the lower 2/3 of the steam boiler for heating to a heat exchanger. Use a stainless steel pump for the boiler water to the heat exchanger. Need temp control to run the boiler without making steam if not needed at that time.

Then mixing valve to temper the water for the floor loop.
Another pump with all the trimmings you mentioned.

Many here, with considerable experience, have done that.
You need a steam/boiler/pipe fitter person.....probably not a plumber.

Check above for "Find a Contractor" in your area.

HVACNUT

You cant use the existing steam piping for a steam to water transfer. Not the way you're thinking anyway. Surface area, regulation. Tell him to look into electric radiant.

Jamie Hall

Well... in principle you could use a steam to water heat exchanger such as you seem to be thinking. In principle. Don't do it -- it's much too complicated. Do it the way @JUGHNE suggested. Simple, easy to control. Any competent steam person can set it up. If you can't think of someone, get in touch with John Cataneo ( @JohnNY ).

STEAM DOCTOR

Water to water heat exchanger. As @JUGHNE said. I have done this before. Works flawlessly. As always, the devil is in the details.

JUGHNE

How about some pictures of existing boiler showing all piping?
Good "boiler porno" goes a long way here.....gets more input!

HVACNUT

I think the OP has the thought of just tapping into the existing radiator piping inside the apartment.

Jamie Hall

HVACNUT said:

I think the OP has the thought of just tapping into the existing radiator piping inside the apartment.

That won't work...

HVACNUT

> @Jamie Hall said:
> (Quote)
> That won't work...

I don't know much, but I know that.

jumper

More accurate to say highly unlikely to work?
Seen stuff that shouldn't work.....
And stuff that should......

HVACNUT said:

> @Jamie Hall said:

> (Quote)

> That won't work...



I don't know much, but I know that.

Jamie Hall

jumper said:

More accurate to say highly unlikely to work?
Seen stuff that shouldn't work.....
And stuff that should......

HVACNUT said:

> @Jamie Hall said:

> (Quote)

> That won't work...



I don't know much, but I know that.

true, oh sage...

rhl

Thanks guys. I pointed my friend at John. I had spoken to him before, but couldnt remember his info.

JohnNY

I'm on this. Saw it this morning. There is plenty to work with to move some condensate through a water-to-water heat exchanger and into a single multi-port manifold. It's an outside-the-box installation, which just happens to be right in my wheelhouse. Thanks for the recommendation, guys.

Snowmelt

Jonny, I need to do that at a job also by me.... do I just do an add a loop , install a flat plate heat exchanger with a S.S. Pump on the boiler side and throw a 007 on the heating side ?

JohnNY

Snowmelt said:

Jonny, I need to do that at a job also by me.... do I just do an add a loop , install a flat plate heat exchanger with a S.S. Pump on the boiler side and throw a 007 on the heating side ?

If that meets your load, then sure. The trick with pulling condensate out of a steam boiler is to get the supply from the top half of the waterline and bring it back into the wet return line close to the Hartford Loop. That allows the water to mix through the sections. I've corrected many installations that almost worked but the installers used both left and right side bottom boiler tappings for supply and return. Doing that just makes the water skate across the bottom and not pick up nearly enough heat.

STEAM DOCTOR

@Snowmelt said:
> Jonny, I need to do that at a job also by me.... do I just do an add a loop , install a flat plate heat exchanger with a S.S. Pump on the boiler side and throw a 007 on the heating side ?
I have never used a flat plate heat exchanger off a steam boiler. I be a bit nervous due to small internals. Possibility of boiler sludge clogging things up. There is also potential of pressure drop/slow heat transfer. Starting pressure is close to zero. Just some food for thought.

JohnNY

STEAM DOCTOR said:

@Snowmelt said:

> Jonny, I need to do that at a job also by me.... do I just do an add a loop , install a flat plate heat exchanger with a S.S. Pump on the boiler side and throw a 007 on the heating side ?

I have never used a flat plate heat exchanger off a steam boiler. I be a bit nervous due to small internals. Possibility of boiler sludge clogging things up. There is also potential of pressure drop/slow heat transfer. Starting pressure is close to zero. Just some food for thought.

Sludge and particles are definitely a concern but that's minimized by pulling water from near the top of the water line. The other option, if you don't like the brazed pate HX (understandably), then use a 20-gallon SuperStor indirect water heater, or similar, and you'll practically eliminate the potential for fouling the HX.

jumper

JohnNY said:

I'm on this. Saw it this morning. There is plenty to work with to move some condensate through a water-to-water heat exchanger and into a single multi-port manifold. It's an outside-the-box installation, which just happens to be right in my wheelhouse. Thanks for the recommendation, guys.

Why heat x? Why not just pump through mixing valve?
Oh and use filter as well as strainer.

STEAM DOCTOR

Running a radiant zone directly off a steam boiler will never work. There is tremendous pressure drop in radiant systems. Lots of small pipe and lots of curves. In addition, there is high likelyhood of sludge clogging things up. Heat exchanger is only real solution. Everhot makes a nice heat exchanger.

JohnNY

STEAM DOCTOR said:

Heat exchanger is only real solution. Everhot makes a nice heat exchanger.

Yes!! I haven't seen any Everhot products around in years but they make great little copper heat exchangers.

Snowmelt

Johnny, not that I’m confused it’s just I never saw it done. I’m talking about getting the water from the top of the supply line and feeding it to the return, so your not pulling it from the boiler tapping which you would do on the boiler add a loop when googled? Do you have a small diagram of this.

STEAM DOCTOR

> @JohnNY said:
> (Quote)
> Yes!! I haven't seen any Everhot products around in years but they make great little copper heat exchangers.

They are still available. I use them all the time. I think that my supplier gets them from Diversified