I am retiring a Bradford-White Combicore, which supplies the radiant system on my addition, due to in the water-heater heat exchanger coil. This is my second failure, with both lasting just under five years and steel coils are for the birds. My intent is to use the Everhot heat exchanger off my steam boiler, which presently supplies one room with baseboard heat. I have confirmed that the Everhot has plenty of BTU capacity for both, but I want some opinions on the right way to get the job done, so I can be sure that my plumber does it correctly.
The feed has an elbow with a thermometer. The plumber suggested installing a Tee below the elbow to feed the radiant loop, using the same tempering valves and circulator that are used on the Combicore set-up. The return would connect with a Tee on the return side of the Everhot.
1. How would you do it?
2. How to prevent each circulator from affecting the other loop?
3. Should there be two expansion tanks, or will the one on the baseboard loop be adequate?
Any advice would be appreciated so I get this job done correctly. I welcome any pros to contact me to do the work. The heating people I talked to don't want the job. But I have a plumber who will do the work.