Ground water
applications
Water in
Water out
Insulated
Ball valve with PT port
Boiler drains
Flow regulator
Control valve
Insulated flex hose
Expansion tank
Return air
Supply air
Ball valve with PT
port and strainer
Note
n
n
Due to the pressure and temperature
extremes, PVC SCH40 is not recommended.
Flow regulation
The preferred method of control
requires a flow control device
mounted on the outlet of the
water control valve. The device
is typically a brass fitting with
an orifice of rubber or plastic
material that is designed to allow
a specified flow rate. On occasion,
flow control devices may produce
velocity noise that can be reduced
by applying some back pressure
from the ball valve located on the
discharge line. Slightly closing
the valve will spread the pressure
drop over both devices, lessening
the velocity noise.
Water coil low temperature limit
setting
Zehnder Rittling’s heat pump
controller includes a user
configurable switch (DIP switch 2
on the PCB controller) to change
the low water temperature cutout
(FP1) setting between water
(30 °F) and Glycol (10 °F). When
loop conditions allow (antifreeze is
used), the FP1 DIP switch should
be set to the Glycol (10 °F) setting
to avoid nuisance faults.
Table 5: Water limit
guidelines
EWT Min.
(°F)
Min. flow
rate
(GPM/ton)
Antifreeze
required?
50
1.5
No
40-50
3
No
40-50
1.5
Yes
20-40
3
Yes
Figure 11: Typical open loop/well application
16
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