Toddmpa
New Member
Hi. I'm working on a drain back system that will move heat from an 80 gal solar hot water tank to a 200 gal heat storage tank. An overview first: A wood stove boiler heats the storage tank through a copper coil HX; the tank heats radiant floors through a second copper coil HX. The solar tank has two coils as well, and sits directly above the storage tank so a drain back system is pretty straightforward: move storage water through the upper coil of the solar tank. The solar hot water is oversized for the shoulder seasons, so connecting the two should give me a few extra weeks of sofa time.
Except .... There's no room to install the pump within the water level of the lower tank, and installing a foot valve is no walk in the park either. Will the system hold prime with a check valve mounted above the pump and situated about 30 inches over the bottom tank water level? Will I need an antisiphon valve as well?
The system will have about 12 feet of head through 1 inch copper and a half-inch HX coil. I have a new but outdated circulator, a 20-42 Grundfos which I don't believe has an internal check valve.
Thanks for your help.
Except .... There's no room to install the pump within the water level of the lower tank, and installing a foot valve is no walk in the park either. Will the system hold prime with a check valve mounted above the pump and situated about 30 inches over the bottom tank water level? Will I need an antisiphon valve as well?
The system will have about 12 feet of head through 1 inch copper and a half-inch HX coil. I have a new but outdated circulator, a 20-42 Grundfos which I don't believe has an internal check valve.
Thanks for your help.
