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[cdie]

just got my wb online last week and like everything but would like to see if someone can help me increase my burn time. 20 plus year old glenwood water heater style pressurized boiler. full time circulation into a pair of water/water heat exchangers in the basement. first exchanger is with the oil boiler witch has two zones of water/air heat exchanger in the air handlers. water leaves that exchanger and goes into another for dhw. I have a plumbing question: currently the wood boiler uses the coils in both w/w exchangers. if I were to replumb so that the wood boiler used the tank side of the exchangers (20 gals each) would that be more efficient? full load of wood is only getting 7 hr burn and would like to do all I can to improve. also, the glenwood has a aquastat driven damper actuator motor for natural draft. the flap is completely closed when water temp is up. would a draft fan improve overall burn time or only give a faster water temp increase cycle? thanks guys

[slimjim]

I would not think it would help, added water does not increase BTU's it only stores them for later use, Help me understand your system, you say your wood boiler is pressurized, why then would you need  any water to water heat exchanger on the oil boiler, a drawing of your setup would help!

[cdie]

slim
cant upload for some reason but i'll try to explain the reason for my setup. wood boiler is not an "outdoor" furnace but one that should be in a basement. (no jacket or insulation) I didn't want to place it there as I didn't have a chimney available and for the same reasons as everyone else as far as wood outside etc. wood boiler has 11 gallon tank on top and +/-25 feet of direct fire box exposure coil. I could not get enough info when planning the install to know whether I could just tap into my oil boiler without some additional water storage in between. oil boiler is a lennox conservator series with only 15 gallons of water. so when a couple of indirect hot water heaters hit craigslist locally I thought they were worth picking up to add margin of error. I thought I was going to plumb the tank side of the exchangers to the wood boiler to allow for this margin but ended up doing just the opposite as I started to think it would be better to have the btu's on the oil side. so at this time the wood boiler is hooked to the coil side of both heat exchangers and the tank side of one is stored oil boiler water and the tank side of the other is stored domestic hot water. I like everything that's happening except I would like to have a longer burn time. might not be possible I understand but this one question of "does it matter which side the btu's are stored" help? other thought I have is going from 180/160 water temps to a lower 170/160 or less if it continues to do the job of heating the home.

[slimjim]

First things first, Do you have separate relief valves, (at least 2) on that wood boiler?

[cdie]

wood boiler totally autonomous. has its own pressure relief, fill valve with reducer and relief, expansion tank, and air scoop with auto vent

[slimjim]

OK I was concerned because I have seen many indoor pressurized units installed in sheds without the proper relief valves and non powered dump zones, they are a bomb in waiting, how do you dump the excess heat in a power outage without a circ or non powered dump zone

[cdie]

upon power loss, my damper springs completely shut. going forward I may put in back up power. no dump zone at this time.