Existing heating piping

Bill Tschinkel

A friend just purchased a new home with 13 zones of radiant heating. Existing heating piping sketch is what was found. I do not understand the pipe configuration of the mixing valve and the zone pump. The old home owner told the new home owner all worked properly? Should the piping be changed (see revised heating piping sketch) or will it operate as existing. Also, should check valves be added? Thank you, Bill

EBEBRATT-Ed

The first drawing the "existing" Mixing valves have 2 inlet and 1 outlets.

If the valve is piped right it should be ok.

Also with that set up the pump can't be allowed to run unless the zone valve is open. It should be wired that way.


The second drawing will not work out with a mixing valve.


What problems are you having? There may be a better way to do this. Are you using outdoor reset?

Rich_49

Circulator belongs inside the mixed circuit as drawn in revised drawing .

Bill Tschinkel

Understood, piping will be changed as per "revised drawing". 24 VAC zone valve will be closed and zone pump will be off when thermostat is satisfied. 2nd question - will a spring loaded check valve be needed on the pump discharge to prevent flow in the off cycle?

Thanks for the help,
Bill

Rich_49

I would just use a circ with an integral flow check as opposed to an individual check valve .