In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
Suggestions wanted (or at least considered) Long story , I hooked up a wood boiler for a friend about five years ago. It is an outside boiler and I did not want to mix the water with the system water so I used an eighty gallon indirect water heater as a heat exchanger. The system was a gravity circulation system from the teens or twenties. A Burnham V34 boiler with circulators was installed in the early 1980's. The house is not insulated and the home owner does not want to compromise the plaster or craftsman style wood trim or siding.
So, to get to the point. They do deep setback and will not change habits. When the thermostat calls for heat so much cold system water returns it causes the oil burner to start. Some other plumber rigged some hokey switch so he could shut off the burner while the wood was going. But now people are away from home and oil burner can't be switched on an off.
My thought was to disconnect the oil boiler from the loop, tie the main together and use two closely space tees to protect the boiler from all the cold system water on a call for heat. I am probably not doing such a good job trying to explain this. I put the guy off for a year or two but now he wants me to do something next week. Every summer I put him off and fall arrives and then it is too late.