circulating hot water heat

Boilerpro_3 · October 2003

> I wouldn't try connecting radiant to it. The 
> water temperature requirements and flow 
> characteristcs are very different. You might, 
> however, be able to run the radiant as a separate 
> zone off the existing boiler using a suitable 
> control system. 
> 
> But if that were my house, I'd 
> locate some radiators and hook them up to the 
> existing piping. If you keep the same pipe sizes 
> as the originals, they'll work great. 
> 
> This 
> would be a good time to install Thermostatic 
> Radiator Valves on radiators in bedrooms, etc. 
> that you like to keep cooler than the main parts 
> of the house. 
> 
> _A 
> HREF="http://www.heatinghelp.com/getListed.cfm?id= 
> 157&Step=30"_To Learn More About This Contractor, 
> Click Here to Visit Their Ad in "Find A 
> Contractor"_/A_

scott w. · October 2003

connecting radiant heating to circulating hot water piping

Bought a 70 year old house that has circulating hot water heat and two rooms, kitchen and dining room radiators have been removed. Would like to install radiant hot water heat in the floor of the kitchen and dining room and possibly two other rooms in the house.. Can I connect the new radiant heat system for those two rooms where the old radiators came off the existing piping? I had two different heating companies look at the job. The first company said no you can't connect to existing piping, the radiant heating would need its own boiler. The second company said yes it could be done. Who to believe?

Steamhead · October 2003

That's probably an old gravity system

I wouldn't try connecting radiant to it. The water temperature requirements and flow characteristcs are very different. You might, however, be able to run the radiant as a separate zone off the existing boiler using a suitable control system.

But if that were my house, I'd locate some radiators and hook them up to the existing piping. If you keep the same pipe sizes as the originals, they'll work great.

This would be a good time to install Thermostatic Radiator Valves on radiators in bedrooms, etc. that you like to keep cooler than the main parts of the house.

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Boilerpro_3 · October 2003

For one...

you certainly don't need another boiler. Using a separate zone for the radiant would be an excellent idea. Depending on the design of the radiant floor and many other factors, I have found that radiant systems often have nearly the same water temp. requirements as pumped converted gravity systems. Say Steamhead, remember, thats what I have in my house! You definitly will need a separate pump for the radiant floor, as Steamhead said, because the flow characteristics are completely different.

Boilerpro

Steamhead · October 2003

I have one too, BP

and depending on how you install the radiant, my water temp would be marginally high to way too high to run radiant. A mixing valve and proper controls would be a must.

That's one reason that when I added heat to the back bathroom, I just installed a radiator.

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scott w. · October 2003

The radiator previously was removed in the dining room to install a bay window with a door in the center. An electic heater was installed under each window on either side of the door.The elecrtic heater isn't effecient. I don't really have a choice of installing another radiator because I can't get beneath the bay to plum the system. So am looking at puting in radiant from basement. The kitchen needs a new floor so would just install radiant heat over old floor and cover with ceramic tile.

Also at some point want to remove a cast iron looking thing recessed in the wall in second floor master bathroom thats chilly and put radiant heat under a new tile floor. Also want to do same to a tiny powder room on first floor by removing radiator to have more room and redo heating in another room that has a small forced air unit that was formerly a porch. It's now enclosed and used as a room. Themaster bath is direcly above this room .

Could the curent boiler be used for the radiant floor heat?

Another question has surfaced. The HW heat has a two pipe system with circulating pump and a390,000Btu weil mclane boiler . Each radiator in the house connects individually off the main and return in the basemen and runs to each indvidual room except for the three radiators on the third floor. Not sure of the pipiing layout to the third floor.

Question. Kitchen to be remodeled and a wall removed. The inside wall to be removed in the kitchen has two hot water heat pipes six inches or so from an outside wall that go strait up to the bedroom radiator above.. Starting in the basement at the main, can I extend these pipes the six inchs so they start the rise on the oustside wall; then make the bend in the kitchen ceiling joist to reconnect to the original piping? Kitchen is a gut job and outside walls to be studded out for better insulation and electric runs as plaster is on the masonary. Is messing with 70 year old plumbing a big mistake?

Will this extran bend in the kitchen ceiling joist cause any problems with the hot water flow to the radiator on the second floor?. This area is the furthest end of the house from the boiler and on the west side which is the weather
side. It also may tie to the radiator above on the third floor but not sure?

Your input is much appreciated! Thanks

heretic · October 2003

Moving pipes

That is the typical setup for a converted gravity system.
Do you have a big house? That boiler is enormous.

Regarding the pipes: IMHO, no big deal to re-route them. Just use the same diameter pipe for insurance. Effect on flow with those big old pipes is not likely to be significant adding a 90, unless rads are already too cold. If you are opening the wall anyways, run pipes inside the wall (unless you like that 'antique' look).
Do not be tempted to use galvanized pipe or fittings- stick with the black.

DIY? Assuming you know how to drain and refill your system properly... You will need at least 2 large pipe wrenches to break the old threads loose. Can take some serious torque. Worst case, be prepared to cut. Since it's heating season, one good technique is to disconnect the pipes and install 2 ball valves off the branch right away. That way you can get the rest of the system running again in short order, and take your time with the rest of the plumbing. You may need a few pipes cut and threaded, which some home centers will do for free. Use sealant on the threads. Both to prevent leaks, and so that they will come apart easily for the next guy!
Best of luck.

scott w. · October 2003

House size

The house is pretty good size. Large living room, a den, large dining room, a kitchen, entrance hall and powder room. Four bedrooms and three baths on second floor. Two small rooms and a bath on the third floor.

I suspect at some point the boiler may have been oversized for the house. Will investigate further.

circulating hot water heat

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