maple1
Minister of Fire
OK.
IMO that temp should be set up to at least 160°. There is no sense in sending wood water any cooler than that over to the system. And typical dT thru a system or unit you would aim for in a design is 20, minumum return temp should be 140 to prevent condensation in the wood fire box. No idea what the dT would be through what you have, but I would start at setting that to 160. Maybe higher depending what the return temp to wood boiler ends up at - wood return should be kept above 140.
By the sounds of it & water going backwards, that means there is no check in that green circ. So what I would try is open all 4 of those valves, except for the yellow one that is closed in the pic. Keep that one closed. Rest open. That should send wood water though the oil boiler when zones are closed. Would be backward thru the green circ but that should be OK. And don't switch that green pump off. When fire dies & wood circ stops, and the oil needs to take over, it should pull thru the zones the 'right' or normal way and not pull much through the wood boiler. Some of that is trail & error, don't know which way has more head. If it does pull through the wood & you don't want it to, a check valve maybe could be added.
See what happens. Part of this is how much each circ flows when it is running.
Also a chance i might have missed something....
IMO that temp should be set up to at least 160°. There is no sense in sending wood water any cooler than that over to the system. And typical dT thru a system or unit you would aim for in a design is 20, minumum return temp should be 140 to prevent condensation in the wood fire box. No idea what the dT would be through what you have, but I would start at setting that to 160. Maybe higher depending what the return temp to wood boiler ends up at - wood return should be kept above 140.
By the sounds of it & water going backwards, that means there is no check in that green circ. So what I would try is open all 4 of those valves, except for the yellow one that is closed in the pic. Keep that one closed. Rest open. That should send wood water though the oil boiler when zones are closed. Would be backward thru the green circ but that should be OK. And don't switch that green pump off. When fire dies & wood circ stops, and the oil needs to take over, it should pull thru the zones the 'right' or normal way and not pull much through the wood boiler. Some of that is trail & error, don't know which way has more head. If it does pull through the wood & you don't want it to, a check valve maybe could be added.
See what happens. Part of this is how much each circ flows when it is running.
Also a chance i might have missed something....
