Indirect Water Heater - Quick Install question

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peakbagger

Minister of Fire
Jul 11, 2008
8,845
Northern NH
I am trying to get my nieces ancient wood boiler running. I was concentrating on the wood boiler side of the install but got to the point where I had to figure out how it was tied into an oil boiler as my niece insisted that the domestic hot water was better when the wood boiler was running. It doesn't have internal hot water coil so it must have been using the internal hot water coil in the oil boiler. After tracing the piping and reading the original manual that a Hearth member uploaded, I have come to the conclusion that what they did was pipe it so that the wood boiler output runs through the oil boiler on its way to the house. Not a great idea as that means that part of the hot water produced by the boiler is going up the stack via the wood boiler. They set the aquastat on the oil boiler low so it only ran when the wood boiler was not running. Unfortunately there is no storage and this boiler is effectively a smoke dragon when there is no call for heat. Definitely not ideal but I don't know how its going to run so I am trying to go one step at a time. So I am now looking at options to get the oil boiler out of the loop and have come to the conclusion the way to go is a boiler mate indirect water heater. Not cheap but probably a good step to a future upgrade

Normally I would put in a priority zone controller and hook up the indirect heater and the single heating zone with a zone valves or pumps on the wood boiler output but am wondering if that is really needed. My thought is its an insulated tank so why not just cut in couple of tees in the line to the main zone and put in balancing valve on the main line to force flow through the indirect unit? It would always be hot but once hot it would just sit there. Once i have this up and running I can set up the valving and skip the oil boiler

Any flaws in this concept? Worse case if the wood boiler is junk then I set up the boilermate on the oil boiler with the correct controls. I want to let them run the wood boiler for the season and then decide if they want to upgrade to storage and a newer boiler. My observations is they really dont have a good handle on seasoning wood so I dont think a gasifier is in their future.