Low load Radinat

Jamie_6

Looked @ a job today that would require It's own heating plant due to the construction of the addition! The heatload for the radiant is only about 11,000 btus & the load for the second floor basboard is only and additional 10,000 btus.

The smallest Oil fired boiler I can get is 50,000 btus! What do I do about short cycling? A buffer tank maybe?

Thanks,

Jamie

heretic

21kbtu

Perhaps a water heater instead of a boiler.

Jacob

Tankless?

In my opinion this is where a tankless such as Rinnai shines. Fully modulating, no standby heatloss, temps up to 180 on comm. model. With baseboard you may have trouble reaching required temps with regular water heater. Just another option.

Joe_13

But if he's stuck with oil?

No choice but a water heater, right? Isn't it inefficent to run a small oil-fired water heater to do this? Smallest
tank is 32gal, aren't you heating a lot of water mass for a radiant loop? The life expectancy of the water tank will never match that of a small boiler. Maybe if this boiler could pick up DHW use with an indirect tank than the 50K BTU units would be a perfect fit.

kevin

is there..

no way to get a set of lines from the existing house to the new addition? size otu a seperate manifold for the baseboard loop and the radiant...I'm sure it is not easy...As one of my general contractors says..NO problems ...just solutions...kpc

heatboy

For something this small.......

an instantaneous electric water heater would be my first choice. Some of them, Seisco for one, actually modulate their input to the load. Much simpler than trying to deal with all of the issues using fossil fuels. Size the baseboard for 140° then add a mixing device to lower the temperature for the radiant.

hb

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Ted_8

My opinion

For what it is worth I might suggest putting the DHW load on the new boiler as well to increase to maximize the BTU's. I would also add in a weather responsive control strategy.

Chris

Steve Ebels

Options

Uh-Uh on the water heater. If it's just a standard type, it won't be able to supply enough temp to the baseboard part of the system. Although it's not ideal, I'd consider a buffer tank. How about using an indirect as your buffer with the radiant coming from the tank side. You could then tap your high temp zone off the boiler supply ahead of the indirect.

We had a similar situation last fall. The homeowner wanted radiant in a 600 sq ft addition. Existing heat in the rest of the home was gas fired forced air. The furnace was a 20+ year old Luxaire. I suggested that we ditch the old furnace and use a new two temp boiler system with an air handler for the existing part of the home. Long story short........ He went for it.

Moral of the story is to be creative, think outside the box, think past what is being asked of you, think about what could be. 95% of the homeowners will at the very least appreciate your suggestions even if they don't accept them. The number that will go for an innovative solution that gives them more options/comfort/economy will suprise you.

hot_rod

Indirectly speaking

when using an indirect tank as a buffer I use the tank as the boiler side and pull the radiant from the coil. This starts the temperature drop, a little, and gives much more volume to the boiler side. Then additional high temperature can be pulled from the indirect (buffer) for the baseboard, etc. P/S is a nice way to make all this happen, hydraulically speaking!

It may also allow you to run real wide delta T on the boiler, maybe a 40 degree (140- 180) which really helps the short cycling of an oversized boiler.

hot rod

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Dale

Really outside the box

Since natural gas isn't available how about a ground source heat pump? Good fuel economy for the low temp loads like floors. I wasn't too keen on them till I spent some time at Wetstock 2 with George Stawnycxyj of earthfire mech of Lehighton, Pa. really explained the concept and costs. As a service person I like alll the parts you work on inside the house in the winter. George is at 610-751-7390 or earthfir@ptd.net Easy guy to talk to.