Installing a boiler stove

[ctb]

Anyone have experience connecting a back boiler wood stove to a couple radiators?
Here's my problem. I've got a stove (small, 8 kw or so ) that has the outlets on the back to connect the pipes. I need to connect it to two radiators, one to the bedroom above, and the other to the bedroom beside the room where the stove sits (ground floor.)
I figure to use 1" copper pipe to connect it all, but that's about where my knowledge ends
I probably need an expansion tank piped in, if so, where, on the return line?
Will the hot water circulate enough without a pump (radiate) or is a pump a necessity? Distances are approx. 15 feet to top rad and 20 to bottom rad.
If a pump is needed what happens when there's a power failure and the hot water can't circulate out of the stove? Any backups for this? (I don't have a generator)
There's not exactly a wealth of information about this on the internet and having had experiences with local plumbers I'd rather not trust them with it. There was a diagram that came with the stove but of course I lost it
Could any of the plumbers on here whip up a quick sketch for me as to how this would go together?

 

[lzenglish]

I have done this with my old wood stove. In my case I bought a boiler rated serpintine coil, and installed it inside of the firebox. I used 3/4" type "K" copper pipe, and routed the inlet, and outlet, to a 120 gallon solar storage tank. I used a small grunfoss cirulator pump to exchange the heated water to the storage tank. You should install a gpm flow meter, and a differential control box, to allow the water to only circulate, when it is 8 to 10 degrees above your storage tank temp. This will allow the water to heat up in the firebox. The idea is to adjust the flow so the pump runs continuous, when you have a fire, and not cycle on and off, or just run thru. Don't expect too much heat out of one of these, depending on your firebox size. They work better in conjunction with solar panels. Good Luck!

Wayne

 

[ctb]

Thanks for the advice Wayne. I have regular gas fired radiators now, just planning to disconnect two and having them run by the woodstove so I can turn the regular heat down to just minimum. The woodstove has a small water jacket in it where the water is heated before going off on its merry journey to the rads. Looks like I'll need a small pump for sure and I like the idea of the control box to allow the temps to come up before circulating.
I worry most about controlling the pressure in the system should the water become too hot, and also what to do if there is either a pump failure or a power blackout when the water is hot and the fire is still roaring.
Not much use having a woodstove if it can't be used without power for fear of burst pipes!

 

[Sureshot]

I don't recall the name of the company but someone here made heater for starting cold engines that were remote and could not utilize electric block heaters. It used one or two check valves and as the fluid heated with a propane tiger torch and expanded it moved itself through the system. You will definitely need an expansion tank of some sort depending on if it is an enclosed pressure system or open to atmosphere.

 

[lzenglish]

I worry most about controlling the pressure in the system should the water become too hot, and also what to do if there is either a pump failure or a power blackout when the water is hot and the fire is still roaring.
Not much use having a woodstove if it can't be used without power for fear of burst pipes!

If you have a closed loop system, you will need an expansion tank. However, If you have a system that is Open to the City, or Well water supply with "NO Check Valve", then your supply line becomes your expansion tank, (so to speak). Also, you will need to have the standard 75 pound pressure/temp safety valve incorporated in your system, be it storage tank, hot water tank etc. As far as your power outage goes, you can buy a deep cycle marine battery, a small inverter, and a tricle charger to handle it. You will also need a couple of relays, wired in, so when your main power fails, they will pick up the small circulator pump load, and differential temperature control box load, then automatically switch back over when your power is restored.


Wayne

 

[ctb]

I don't recall the name of the company but someone here made heater for starting cold engines that were remote and could not utilize electric block heaters. It used one or two check valves and as the fluid heated with a propane tiger torch and expanded it moved itself through the system.

I've used a length of stovepipe, a tiger torch and a tarp many a time in the Yukon to unthaw a frozen engine. Only takes an hour at 55 below. You can get the same temps in Sask. so you know what I'm talking about

I think the distances from the stove to the rads necessitate a pump although I'd ideally like to cut out an outside energy source.

 

[ctb]

Thanks Wayne. It will be closed loop so will need the expansion tank along with the pressure relief valve. If the water gets too hot and trips the pressure relief valve, I'm guessing it's going to dump the hot water out so I'll need a tank to catch that too.

I'm going to try make a drawing of the circuit and then I'll post it to see what you guys think. Thanks for all the help.

 

[lzenglish]

Thanks Wayne. It will be closed loop so will need the expansion tank along with the pressure relief valve. If the water gets too hot and trips the pressure relief valve, I'm guessing it's going to dump the hot water out so I'll need a tank to catch that too.

I'm going to try make a drawing of the circuit and then I'll post it to see what you guys think. Thanks for all the help.

Your are Very Welcome "ctb". As far as your relief valve goes, just pipe it to the nearest drain, or outside like I did mine (15 foot run). I used 3/4" copper, and a short piece of 3/4" flex pipe off the valve, to allow for any movement such as earthquakes, etc.

Wayne

 

[Sureshot]

I've used a length of stovepipe, a tiger torch and a tarp many a time in the Yukon to unthaw a frozen engine. Only takes an hour at 55 below. You can get the same temps in Sask. so you know what I'm talking about

I think the distances from the stove to the rads necessitate a pump although I'd ideally like to cut out an outside energy source.

My stovepipe with elbow is on the outside rack. Tiger torch and spare tanks filled. Tarp and winter fronts installed. Ready.

 

[philjafo]

If you have a closed loop system, you will need an expansion tank. However, If you have a system that is Open to the City, or Well water supply with "NO Check Valve", then your supply line becomes your expansion tank, (so to speak). Also, you will need to have the standard 75 pound pressure/temp safety valve incorporated in your system, be it storage tank, hot water tank etc. As far as your power outage goes, you can buy a deep cycle marine battery, a small inverter, and a tricle charger to handle it. You will also need a couple of relays, wired in, so when your main power fails, they will pick up the small circulator pump load, and differential temperature control box load, then automatically switch back over when your power is restored.


Wayne

75 lbs pressure and temp valve is specific for domestic water heaters, you need boiler specific 30 lbs pressure only relief valve, and a check valve alone would not be up to code, you need a back flow preventer and fill valve, so that if it over heats and blows the relief valve the fill valve automatically refills the system. Codes are in place to protect you heating water in a pressurized system without ALL of the required safety features is a recipe for disaster. If you call an HVAC company out (we're not cheap but a safe effecient system is worth it) I'm sure they could help you hook your boiler up to the existing system and if its not enough to satisfy all of the demand I bet it could do at least half, then you wouldn't need to turn the gas boiler down to min. It would just run a lot less.

 

[BadgerBoilerMN]

Phil has it right. At least an intelligent and safe design. Saving money is good, your life or serious injury is more important. Don't expect much is also right. These things can be calculated unless you like to work hard with short returns.