New Empyre Elite XT 200

[Plpethier]

Just picked my new woodboiler and have been spending hours here on hearth.com researching what I'll need to plumb it in to my existing propane boiler. There's a ton of great info but no exact matches to my application that I could find. Attached is my sketch of what I believe I will need. Does anybody see any major problems with what I have? As the temperature outside starts to drop I'm anxious to get this thing going.

I could use some help on what I'll need for an aquastat on the woodboiler loop pump. If the water is not circulating where do I get a temperature reading to turn the pump on? Can I put something on the stove pipe that would tell the pump to start? I think I can put a aquastat on the woodboiler loop for the second pump and one just before the plate exchanger for the propane boiler loop.

Also what is needed to figure out the size of the plate exchanger? I calculated the large loop pump with 6.6gpm and about 14ft of head loss. I found a 14 plate 3" x 8" exchanger rated for 8gpm. Will this be big enough to do the job?

Thanks in advance for helping

 

[mustash29]

Central Boiler has some decent drawings of various different plumbing drawings for unpressurized OWB's.

You light a fire in the Empyre and turn on the temp controller, which turns on the firebox blower and cycles it on / off as needed to maintain the temp setting. The WB pump should be running as well. The Danfoss valve on the ESO will provide low return water temperature protection. Basically the WB will heat itself up first, then is starts dumping heat towards the house. The blower cycles as needed but the pump stays running 24/7.

Your ESO to HX pump needs to run 24/7, to prevent freezing, and to keep the BTU's flowing from the outside into the house. Make sure you insulate and water protect your underground lines well.

Your 3rd pump from HX to propane boiler needs to either:
- Run 24/7 to keep the propane boiler / distribution system in hot standby. Know as a "wrap around pump". Necessary if it has a tankless DHW coil in it.
- Could be told to turn on only during a call for heat. T-stat would then be opening a zone valve & turning on the propane boiler's circ pump to distribute heat and also turning on the HX to propane pump to get that heat.

Dial your propane aquastat down and it should never fire, unless needed for backup. If you want automatic backup and the same temps, you need more sophisticated controls & wiring.

I researched the Empyre. I believe it's temp controller has a 12 deg differential, so it would run 168 - 180. Hopefully you can keep warm water in the house loop and HX so you could set the propane temp controls to 140 - 150 ish.