Due to changing household requirements, I have decided to mothball my custom hydronic heating system. This includes removing the "boiler," which is uninsulated and occupies a huge amount of precious living space. A large wood-burning fireplace wrapped with large iron water pipes heats the boiler; there's a backup LP gas heater, too. All the water pipes are embedded in the concrete slab; no pipes are ever exposed to temperatures lower that 40 degrees F. Well, I suppose that, if the house were unoccupied and all heat sources shut off, a prolonged
extremely cold period could result in mild freezing exposure to one small section in a closet in the garage.
My questions:
- Once the boiler is removed, what should I do with the remainder of the system? I mainly want to prevent corrosion in the pipes and pumps because I'd like to retain the option to replace the boiler and upgrade the system. But I realize that this may not be possible after years of disuse.
- Is it possible to simply close each of the three zone loops? This would allow me to run all the pumps occasionally to prevent them from becoming 'frozen.' Somewhere I read that draining the system is a bad idea because you can't ever get all the water out and the added air will accelerate corrosion.
- Should I add a corrosion inhibitor?
- What should I do with the fireplace loop if I want to continue burning wood? I suppose I must remove all the water from that loop and leave it open or else the water will boil and burst a pipe. Then I suppose that the extreme heat will boil away any remaining moisture and
thereby prevent corrosion.