2 boiler (1 stove 1 range) interconnected system

[tgarland]

Hi.
I currently have a sealed central heating system based on a range cooker/boiler. I'm planning to buy a wood stove with back boiler and have it hooked up to the said system. My current system has 3 zones - living,bedroom, and cylinder hot water. I want to be able to have the stove and/or range heat individual or all zones. My plumber tells me that connecting the wood stove into the existing system would mean that the central heating system would have to become open which might reduce its efficiency. To solve this problem he is recommending an interconnect system which is a central unit which takes its heat source from two different independent sources (range and wood stove) and allows me the flexibility I need whilst keeping the current sealed system sealed . Each zone would have its own pump. I have attached a couple of pictures to illustrate the potential layout. . As the outlay is considerable I wanted to get some advice on whether the gain would be substantial enough compared to simply connecting the wood stove into the current system, going from a sealed to an open system and using my current zoning setup. Any help or advice would be much appreciated.

rgds

tom

 

[Eric Johnson]

Wow.

I'd stick with a closed-loop, pressurized system and a storage tank rather than trying to get everything to cooperate with a heat exchanger. Quite frankly, I've never seen a range that doubles as a domestic heat boiler, nor have I seen a conventional wood stove rigged up to heat water, much less an open-loop one. What you seem to be proposing would be a technical challenge and a difficult balancing act, IMO.

For what it's worth, I recently ran across a boiler that looks and acts like a wood stove, as briefly described by this link.

https://www.hearth.com/talk/threads/2159/

If the promotional material is to be believed, you get the benefit of having a pressurized system that should tie right in with your existing set-up, assuming that the range/boiler is pressurized as well.

Open loop, non-pressurized boilers are typically outdoor units. You have big potential problems with corrosion and contaminants in the water or glycol because of the presence of oxygen, and you need a heat exchanger to mate them to a typical, closed-loop pressurized system.

 

[Eric Johnson]

Is your range natural gas?

That b/w diagram looks like something out of the late 1800s or early 1900s. I can see the heat exchanger and the expansion tank in the attic. Old school.

I think you could accomplish what you're trying to do with a lot less equipment, plumbing and potential headaches with a different wood-burning appliance.

 

[wg_bent]

I have to agree with Eric. I don't know of any wood stove that has the BTU output to handle being cooled by that much water and remain remotely efficient. You ought to be looking at Tarm boilers.

Keep a nice small Wood oven in the kitchen for the asthetics.

 

[elkimmeg]

We had this discussion before where the wood stove becomes a missile with steam buildup and explodes

 

[wg_bent]

We had this discussion before where the wood stove becomes a missile with steam buildup and explodes

Cool Just do it outside Kinda like tossin a wet turkey into 5 gallons of boiling oil?