Has anyone ever run baseboard heat off a water heater?


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Old 12-21-04, 10:14 AM
captnpt
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Has anyone ever run baseboard heat off a water heater?

I have a porch that has been converted to a year-round room. Currently the room has electric baseboard heat. A relative told me I could heat the room with a small water heater and some new baseboards. Is this wise? And do i need a pump to circulate the water?
 
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Old 12-21-04, 02:24 PM
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Forget it .A water heater dont have the btu recovery that you need for the hot water. And you would need the pump also.

ED
 
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Old 01-11-05, 07:57 AM
jlex
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baseboard heat from hot water heater

I just completed the identical project: cutting off our porch (sunroom) from the main boiler & patching in a hot water heater as the heat source.
Why you ask? Because I like to heat with wood & running the big boiler just to heat the more remote sunroom is inefficient... most other outlets in the house are cast iron & the volume of water it must heat just to heat the baseboard line is ridiculous.
Because the local hardware store had a 30% off sale, I decided to take the plunge & buy a 30gal natural gas heater, expansion tank, fittings, valves, etc. Luckily, I had the room separately zoned off previously, so I used the same pump & thermostat.
Have had the system running for only about a week now (struggled with a bit of air in the line for a couple of days, but its okay now).
With just the wood burner running, this 8 window, 2 door room has stayed at 65 degrees. I suppose it could go higher if I closed the two entry doors to the rest of the house, but I'm content with it.... btw, I'm in Northwest PA so it's not balmy here.
Ed is probably right about the btu output... when it was hooked up to the big boiler, I could run the temp up to 85 if I wanted to, but 65 feels great to me. Temp control setting is at the highest. We have an unvented gas heater in the room that we haven't had to use yet.
The real test will come this weekend with single digit temps... am really anxious to see how it handles it.
Apparently, they use hot water heaters rather than boilers in the floor tube heating arrangement due to the lower temp. Good luck.
regards,
jlex.
 
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Old 01-11-05, 10:56 AM
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To answer your specific question, yes, I do know someone that actually did this for a very small den.

Chris
 
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Old 01-11-05, 02:43 PM
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Chris,

The original questions were "Is this wise? And do i need a pump to circulate the water?"

I did not see a question about did we know someone that had done it.

Ed is correct, domestic water heaters do not have the BTU capacity required to operate efficiently, and you still need a circulating pump, thermostat, etc.

View is not worth the climb IMO.
 
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Old 01-11-05, 06:27 PM
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Electric water heaters are out of the question, capacitywise. Gas water heaters are probably not going to have much excess capacity......but OIL will do the job nicely. Be sure to calculate the heatloss first and size the baseboard for water temp of 140 degrees. You will probably need double the amount of baseboard as if the water temp was 180 but you can do it if the heater has the moxie. That is th eproblem jlex will face as his baseboard was sized for much hotter water and the btu output of the existing baseboard will be insufficient to keep the room comfortable on single digit temps. You must also use a bronze circulator if the water will be shared with the faucets.

Ken
 
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Old 01-12-05, 11:00 AM
jhb
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You could use a hot water heater through a radiant floor setup.

Also, I have seen low profile baseboard heaters that just clip onto 3/8 Pex tubing. I cannot remember the name of the company off-hand.
 
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Old 01-13-05, 01:43 PM
jlex
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Interesting thread. I'm the guinea pig here. Temps will be dropping into the single digits & the 20's beginning tomorrow (Friday) so we'll put the 30gal. hot water heater to the test & I'll report next week.
The room itself is approx. 30' X 15'. Has 8 good sized windows (which I previously replaced), 2 outside doors, & is connected to the rest of the house by 2 sets of operable French doors. This addition is brick veneered onto hollow block with NO insulation in the walls. The tin roof may have some rudimentary insulation under it.
I have 45' of baseboard running along the outside walls.
This is a completely closed system... no faucets connected... just a closed loop.
So far I've been been very pleased but we've had warmer than usual weather. Time will tell.
On my water heater, the highest thermostat setting bumps the temp up to 160... that's only 20 deg less than what the boiler would otherwise do.
Does anyone out there know if you can replace the gas control valve on a conventional water heater to bump the temp up to 180??? I'm not sure I'll need it, but it would be an interesting thing to do for a bit more headroom if needed.
regards,
jlex.
 
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Old 01-19-05, 06:25 PM
Sam R
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My basement family room is 1000 square feet and baseboard-heated with a 40 gal gas-fired hot water heater for two years now and it works just fine. It also gives me a back-up if something happens to the main hot water heater. Late last year the main hot water heater went out for two days and I used the smaller one to provide hot water upstairs for showers, etc. while I figured out what the problem was with the main one.
 
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Old 01-21-05, 08:22 AM
jlex
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As a follow-up to my earlier post: it's 8 degrees F here in NW Pa. My 30 gal hot water heater has kept my sunroom at 67 degrees. I'd have to turn on the gas space heater to get it any higher, but it's okay with me. I may want to toy with putting another 6' of finned baseboard in this summer just for something to do... Should bump up the temp by a few more degrees... I know the hot water heater (which is rated at 40,000 BTU) and is running at 160 degrees can leave me with more heat, because the return line is still plenty hot.
I may want to do some serious BTU loss calculations on the room just for the heck of it to see what the heater can do with additional baseboard.
Just my experience.
regards,
jlex.
 
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Old 01-23-05, 12:05 AM
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Captnpt

Do not try to use a water heater for heating your domestic and space heating. The baseboard is VERY thin wall & will not withstand the pressure used for domestic. Also being so thin, it will be eaten away very quickly by the oxygen in the domestic water, not to mention if your water is acidic the baseboard will go away even faster. All of this spells F L O O D.
 
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Old 01-28-05, 06:33 AM
jlex
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It was 5 deg. below zero this AM in NW Pennsylvania & my sunroom is at 70 degrees. I'm perfectly satisfied with the current arrangement, & it looks like I won't bother adding more baseboard.
I respectfully disagree that using a hot water heater can have the dire consequences pointed out by Grady. If plumbed properly with an expansion tank to take any additional pressure from heated water, a closed loop system will not generate pressures any where near what it would take to blow out a copper line. Mine runs at a modest 12 psi. Additionally, the temp/pressure relief valve on the hot water heater will open long before any weird pressure buildup blows a copper line.
Also, in a closed loop system, an air purger will, within a few days, take the dissolved oxygen out of the heated water so there should't be any worries there. As far as acidic water goes, you should be good for 75 yrs. before corrosion from acidic water should be a problem; you'll get more erosion from the water being moved by the pump than you will from acidic water (especially water containing no oxygen). Besides, wouldn't a conventional boiler use the same water complained of? If the HO has really nasty water, I'm sure a water conditioner is in order to protect all plumbing appliances in the house.
You may have those kind of concerns if you had it as an open system whereby you also used the non-dedicated heater for hot water consumption too. I wouldn't advise that; the btu demand on the heater would be too great. It can only work with a closed loop system where there is no loss or gain of water during usage.
Also, if there's a concern that you don't have enough room for baseboard to meet the btu loss of the room, look at using radiant panels; I have heard good things about them re btu output & being able to run at lower water heater type temperatures.
I got lucky with my setup w/o first doing an analysis on the room. Actual plumbers don't want to be called back on a job, so they'll be conservative in their work & will call for a heating appliance they KNOW will do the job (namely, a boiler). With a little hot water heater, you'll either be lucky & work it out with sufficient emitters or not. If you're doing your own work, I'd say take the chance... the cost will be minimal.
jlex.
 
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Old 01-28-05, 08:43 PM
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Jlex

When I was reading the original post, I got the impression the water heater was used for domestic as well as heating. The way you have done yours should work just fine. In essence, you have a boiler. The reason for my comments was I saw a system where the homeowner just tapped into his domestic system & used it for heat also. He had no reducing valve, expansion tank, or any means of removing oxygen. Needless to say, the baseboard lasted virtually no time. Sorry for the confusion.
 
 

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