controllers with 2 temps

ws9876

some people with a woodstove might like to run a heat exchange system to heat water...it comes on when the room temp gets above 70
and turns on a pump to run fluid thru a panel next to the stove (not in the stove)and then thru coils in a hot water tank. But only if the water in the tank is less than 95 and not over 105.....so you need 2 probes that can short the pump system if either parameter is not met.. and one of them has to have a hi/lo capability .. what controller would you use for this ..especially the lower cost ones..

mike95490

Wood stove must be Pressure & Temp protected. and relying on pumps (that fail or loose power) is a bad idea.   I use thermal siphon, totally passive and all high points protected with  T & P vented valves (like on a standard waterheater)

ws9876

if its a drainback setup there is no problem...of course there would be prv in appropriate places. how does yours work exactly?? 

MichaelK

Mike, I'm also looking into installing a thermosiphon in my kitchen cookstove.  Could you please quantify some performance values about yours, like how long of a burn heats X gallons of water, Y degrees above ambient?

mike95490

So, the mfg of the Heat Loop should supply the apx BTU the loop is rated for.  Here is one link
http://www.firespeaking.com/media/articles/details-of-plumbing/
  My masonry heater (2hr fire) will be vastly different than a wood stove (8 hr fire)
For thermal siphon, BE sure the pipes have a slant, no loop, no high/lo which will block the flow and cause a steam explosion.
There should be no "gurgling" it should be absolutely silent.  Loop should be SS boiler tube, connected to copper, not plastic.

And attached is my "schematic"    i estimate 30K BTU each firing, and keep the 80 gal tank about 90 - 110 F in the winter