On demand for heating, the heat pumps will absorb heat from the loop circuit, whereas on demand for
cooling, the heat pump will reject heat to the loop circuit.
General Design Steps
HRP Wiring Diagram
Only in very cold weather with most or all units heating is it necessary to add heat to the water
with a water heater. This is done when the temperature of the water loop falls to 65
o
F(18
o
C).
The amount of this heat is reduced any time one more units are operating on cooling. The
central water heater is never larger than two-thirds the size required in other systems but is
usually less because of diversity.
