10
Typical Open Loop Piping
Open loop systems require a water solenoid valve to turn on the
water when the heat pump compressor is energized, and to turn off
the water when the compressor is off.
A slow--closing motorized valve (MVBR3F or MVBR4F) is
recommended to help reduce water hammer. A flow regulator
limits water flow to avoid using more water than the heat pump
requires, which wastes water and increases pumping costs. A hose
kit provides vibration isolation, as well as convenient fittings to
install P/T (pressure/temperature) plugs for checking water
temperature and pressure drop at start--up and during
troubleshooting.
Fig. 9 shows the typical piping arrangement for a single solenoid
valve. For single speed heat pumps and smaller two--stage heat
pumps (3 tons and smaller), one valve is typical. For larger
two--stage heat pumps, there is an opportunity to save a significant
amount of energy (and avoid wasting water) with the use of two
solenoid valves, one for first stage, and both for second stage (Fig.
10).
1” hose barb
x 1” MPT*
1” rubber hose*
P/T Plug*
Heat Pump
Elbow*
MVBR4F solenoid valve
Part of HK4MM hose kit
Consult local regulations for discharge requirements
Consider variable speed pump in place of pressure tank and pressure switch
LWT
EWT
1” MPT x 3/4” MPT
*
**
***
†
††
1” ball valve
Piping to discharge***
Heat Pump
1” hose barb
x 1” MPT*
(optional)
1” ball valve
Pressure Tank
†
Submersible
Pump
††
MVBR Solenoid Valve
Flow Regulator
Fig. 9 -- Single Solenoid Valve
Solenoid Valve
Stage One
Solenoid Valve
Stage Two
Flow Regulator
Stage One
Flow Regulator
Stage Two
Ball Valve
From Heat Pump
NOTE
: Refer to Fig. 18. Wiring kit #4129 is recommended for easy 24 volt connection staging solenoids with compressor.
Fig. 10 -- Two Solenoid Valves