Solution for radiant heat and hot water

Steve Garson_2

I am planning ahead for the eventual demise of my six year old 45 gallon Bradford White Combicore Hot Water Heater. It supplies my domestic HW and the heat for my addition which has radiant heat under hardwood floors. The heat loss in the rooms is around 22,000BTU. This seems like a light load for a boiler.

The rest of the house is heated with a new WM SGO4 for steam heat, with a Everhot heat exchanger to heat a single room with baseboard hot water. The SGO-4 is closely matched to the radiation of the steam radiators.

Any ideas on how to plan ahead for a solution? My understanding is that ten years is the maximum life on the hot water heaters, so I would rather plan the work for the summer, than wait for a failure in the winter. Or am I not giving the water heater enough credit to possibly last longer? I have both oil and gas.

Unknown

combicor? you'll be lucky if it lasts that long. that's a little snide, but they are not known for long term reliability.

where are you located? How large is your family/domestic load?

Steve Garson_2

Family of four. Long showers. Laundry.

Unknown

and location?

Steve Garson_2

Newton, MA: ten miles west of Boston.

Unknown

well, you're borderline, and I suppose a bit depends on what you are comfortable gambling on for fuel prices over the next ten or twenty years.

but assuming we can't tack this load onto your steam boiler, I would probably go for a small mod/con boiler and a storage tank for domestic. something like a munchkin T50 perhaps, with a nice low minimum modulation rate, or a weil mclain Ultra 80.

Definitely pricier, but if your radiant is low temp, I think you'd like it.

Steve Garson_2

What do you mean as "on the borderline"?

My radiant system needs a water temp of 150* on design days, since it needs to penetrate the wood floors. This gives an 85* floor temp. Most of the time it runs with 140* water.

I like the idea of using both oil and gas as a hedge. The steamer is oil, so gas for the hot water works for me.

Unknown

sorry, I meant that your load is not high enough that using a high efficiency heat source is a hands down, no brainer solution; it could go either way.

If you need 150 at design, such a boiler with an outdoor sensor could run much cooler most of the time and eke extra efficiency out of the system, which is nice. It would improve your system too unless you are using outdoor reset already.

Also, when making hot water the boiler will be more efficient than your water heater as well.

hr

The CombiCor is now

called the Defender. It has been upgraded with a large diameter enamaled steel coil. Several sizes in gas, LP, or oil fired versions.

The life expectancy of any tank style heater is directly related to the amount, and quality of the water run through them. 10 years for that price is not a too bad. A lot less upkeep and lockout hassle than some of the modcons, and any plumber, anywhere can repair one

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Unknown

ah, that's cool. What do you think of the new defender? Cause given the track record I've been privy to, I would never spec an old-style combicor... always external heat exchange.

hr

I'll give BW a

second chance. It took a little long but they did come up with a good fix in my mind.

Given a choice I feel the HX inside the tank surrounded by water will be a bit more efficient. And no pump required. The new design has the 1-1/2" coil at the top of the tank, out of any sediment build up area.

Mod con would still be my first choice, as a heating appliance, But there are plenty of applications for a dual use combo WH.

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Unknown

Yeah, it is nice to be able to drop a pump. Thanks for the feedback HR, I"ll have to take another look at the unit.