Enertech Global, LLC
15
WS Rev. E Models
Installation and Operations Manual
Open Loop Piping
Placement of the components for an open loop system are
important when considering water quality and long term
maintenance. The water solenoid valve should always be
placed on the outlet of the heat pump, which will keep the
heat exchanger under pressure when the unit is not
operating. If the heat exchanger is under pressure, minerals
will stay in suspension. Water solenoid valves are also
designed to close against the pressure, not with the pressure.
Otherwise, they tend to be noisy when closing.
A flow regulator should be placed after the water solenoid
valve. Always check the product specification catalog for
proper flow rate. A calculation must be made to determine
the flow rate, so that the leaving water temperature does not
have the possibility of freezing.
Other necessary components include a strainer, boiler drains
for heat exchanger flushing, P/T ports and ball valves. Ball
valves allow the water to be shut off for service, and also help
when velocity noise is noticeable through the flow regulator.
Spreading some of the pressure drop across the ball valves
will lessen the velocity noise. Always double check flow rate
at the P/T ports to make sure the ball valve adjustments have
not lowered water flow too much, and essentially taken the
flow regulator out of the equation. It’s a good idea to remove
the ball valve handles once the system is completed to avoid
nuisance service calls.
Hose kits are optional, but make for an easier installation,
since the P/T ports and connections are included. The hose
also helps to isolate the heat pump from the piping system.
Since the heat pump can operate at lower waterflow on first
stage, two stage units typically include two water solenoid
valves to save water. The flow regulators should be sized so
that when one valve is open the unit operates at first stage
flow rate, and when both valves are open, the unit operates
at full load flow rate. For example, a 4 ton unit needs
approximately 4 GPM on first stage, and approximately 7
GPM at full load. The flow regulator after the first valve
should be 4 GPM, and the flow regulator after the second
valve should be 3 GPM. When both valves are open, the unit
will operate at 7 GPM.
Open Loop Piping Example
IN
OUT
S
HEA
T PUMP
Single
Speed
Units
S
S
Two-
Stage
Units
Boiler Drain
for Heat
Exchanger
Maintenance
(2 required)
P/T Port
(2 required)
Strainer
Ball Valve
(2 required)
Flow Regulator**
Water
Solenoid
Valve
**See product specification
catalog for flow rates.
Optional
Hose Kit*
*Hose kit is used for piping
isolation, and includes
fittings for P/T ports.
From Well
Discharge Line
Not recommended for 3
ton and smaller. Use single
solenoid and flow
regulator.
Section 5: Unit Piping Installation