Outdoor Wood Boiler to house LP boiler plumbing

[@WildBill1511]

Ton of work there, but worth the time!

[@karonosphere8390]

Great video! I’m in a similar boat where in the past year we changed over 2 forced air oil furnaces to one propane boiler combi system that does both radiant in floor heating for half the house and also goes through a heat exchanger forced air for the other older part. With that huge investment completed the cost of heating this house which is not small is still on the painful side and so I got myself a used wood boiler and I’ve roughed in 2 circuits, one for the house and the other for a pool. I’m moderately handy and have done a good amount of plumbing and electrical work however this whole boiler set up had me a little more than nervous to tackle but my HVAC guy is MIA so I may be forced to tackle this myself. I’d like to plumb it similar to yours where the wood boiler does most of the work but the LP would take over if let’s say we go away or for whatever reason the fire in the wood boiler goes out. So how do I do it so it’s automatic? Your set up is not automatic correct, you have to manually select whether your heating through the plate exchanger (wood boiler) or your LP boiler? how did you size your plate exchanger? How did you drain your lines to be able to tie in your plate exchanger (I haven’t fully educated myself on that side of things)? Any help is appreciated.

[@twosawacres8096]

Hi there, glad to see folks are getting something out of these...lol When I started digging into all this there wasn't a single video showing my setup. I sized the plate exchanger just by talking with a good buddy of mine who's a pluming and heating specialist for 40+ years, but basically 2-3k sqft, a 40 plate will work just fine. As far as the LP being automatic, my setup could work as an auto back up, I just turned off the lp gas to the unit so it cannot, but if I just turn on the gas, light the pilot, and turn down the temp sensor (the one that tells the lp boiler to kick on) to lets say 150, then if the wood boiler is shut down or runs out of fuel, the lp would work as advertised. Furthermore, in this case, it would also help keep the water in the OWB from freezing because the plate exchanger would be working in the opposite direction. The LP boiler system doesn't know where the heat is coming from (LP boiler or plate exchanger), there's some weird physics within the lines that somehow the hot water from the plate exchanger will flow (even without a circulator pump) into the LP boiler its self. My system has shutoff valves on both sides of the LP boiler and each side of each zone loop, so I just shut off all the valves and cut the feed line into the boiler, I did have a small about of water come out (just had a 5 gallon bucket ready), after everything was plumbed, I used a couple garden hoses and flushed the system and got all the air out (that's a whole other process I should make a separate video on).

[@karonosphere8390]

Thanks for the info. Sorry for the very delayed reply. I read the response, then got distracted and never came back until now. One issue I may be facing with mine is that the LP boiler is triggered on when there is water flow. So it doesn’t matter what temp I set the incoming water to. That’s something I need to figure out but I think with some automatic water temp sensor valves this can be accomplished. I will share once this work gets completed which is way overdue.

[@shawnphibbs4380]

@@karonosphere8390 Hey there from Muskoka! I’m tackling same situation as yours right now. (Lp Combi as automatic backup to wood boiler) did you end up figuring it out?

[@karonosphere8390]

@@shawnphibbs4380 I’m currently waiting on a quote from an HVAC guy that came in with a lot of confidence and gave me a brief explanation of how it needs to be done. He’s done them before but is waiting to hear back from the manufacturer of my wood boiler which is a Heat Master G200s in regards to installing the appropriate size heat exchanger. Anyways hopefully this guy can do it the way I want and I’ll do my best to share the details.

[@josephdimassi6300]

Great explanation

[@twosawacres8096]

Thanks for the comment and watching. I didn't find a single video of this type of setup, glad to hear some folks are getting something out of it.

[@michiganpropertycontrol1243]

Great video How much wood do you use?

[@twosawacres8096]

Michigan property control? Not sure I should be talking to you! 😂