Hi all, We are getting settled into our new (to us) home and I want to start on the wood boiler install. We have a oil boiler with coil in it for dhw, the boiler feeds three zones via n/c solenoid valves. I would like to install the wood boiler in series with the oil boiler, using a n/o solenoid valve to recirc the hot water coming from the wood boiler so the oil boiler will stay hot keeping the dhw hot. When a zone calls for heat the n/o valve will shut, the n/c zone valve will open, the entire time the hot water will flow through the oil boiler so dhw will always be available. So has anyone done an install like this and or can anyone recommend a brand model valve that is good for this application (1" n/o valve)? Is there a zone control relay block that is commercially available or will I need to make my own? If I make my own I imagine I will need diodes between the zone valves so power will not travel from one zone to the next. Any help is appreciated!