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This summer I'm going to be replumbing my heat dump zone for my outdoor wood boiler. I know typically a dump zone is a gravity fed system with a N/O valve that allows flow in a power outage. I'm not worried so much about the power outage situation as I am an over fire situation.
Right now my dump zone is tied into it's own loop with a water/air heat exchanger and fan. I'm wanting to tie it into my current garage heating loop and do away with the other WAHX setup. The dump zone will only be used in the case if over load the firebox and my hot water storage tanks won't take anymore or at least won't take the BTUs fast enough to cool the boiler. I'm trying to avoid my boiler going into idle.
My boiler will be heating storage tanks which I draw from for my heat loads. It heats the tanks via a plate heat exchanger. The storage tanks are in my garage as the boiler is in a shed just outside. The FPHX is also in the boiler shed. So from plate HX to storage tank it runs underground.
I've drawn up a plan I'd like feedback on, good or bad, to see if you guys think this will work. Anything i should change let me know. My thinking is if the dump zone needs to come on it will open the diverter valve to the dump side. This will send water up into my current garage heating loop. When the dump is activated it will also switch on my current garage loop circulator to help with the added head of the garage loop. Thought being the pumps would be in series so it should be ok?
Let me know what you guys think.