
Flow-Sensing Devices
Use either flow switches or differential pressure switches
in conjunction with the pump interlocks to verify evapo-
rator and condenser water flows.
To assure adequate chiller protection, wire the chilled-wa-
ter and condenser-water flow switches in series with the
appropriate water pump interlock. Refer to the wiring
diagrams that shipped with the unit for specific electrical
connections.
Unless stated otherwise, all flow sensing devices must
be field supplied. Be sure to follow the manufacturer’s
recommendations for device selection and installation.
The requirements of paddle flow switch are as follows:
Figure 8. Flow switch installation
12
3
4
555
1. Flow switch body
2. One (1) pipe size larger bushing to avoid paddle interference
3. Pipe couping
4. Flow switch paddle
5. Five (5) pipe diameters (no turns or ttings)
Also, review the general flow switch installation guide-
lines listed below.
1. Mount the flow switch upright in horizontal section
of pipe. Allow at least five pipe diameters of straight,
horizontal run on each side of the switch. Avoid loca-
tions adjacent to elbows, orifices and valves whenev-
er possible.
2. To assure that the flow switch operates as designed,
adjust the length of the flow switch paddle to com-
pensate for the pipe diameter and the height of the
coupling tee used to install the switch.
3. Install the flow switch using a coupling that is large
enough to allow the insertion of a bushing one pipe
diameter larger than the flow switch base (Figure 8,
p. 20).This will prevent interference with the flow
switch paddle.
4. Verify that the direction-of-flow arrow on the switch
points in the same direction as actual water flow
through the piping circuit.
5. Remove all air from the piping circuit to prevent pos-
sible flow switch “fluttering.”
6. Adjust the flow switch to open when water flow is
less than normal.
DNOTICE
Proof of Flow Switch!
Evaporator and condenser water circuits require
proof of ow switches. Failure to provide ow
switches or jumping-out of switches could result in
severe equipment damage.
Evaporator and condenser proof of flow switches (either
flow or Delta-P) are required in series with the pump
contactor auxiliary shown on wiring diagrams.These
switches are used with control logic to confirm flow prior
to starting a unit and to stop a running unit if flow is lost.
For trouble shooting, a viewable diagnostic is generat-
ed if a proof of flow switch does not close when flow is
required. Failure to include the condenser proof of flow
switch and jumping out this switch could cause the unit
to stop on a secondary level of protection such as high
condenser pressure. Frequent cycling on these higher
level diagnostic devices could cause excessive thermal
and pressure cycling of unit components (O-rings, gas-
kets, sensors, motors, controls, etc.) resulting in prema-
ture failure.
For the thermal flow switch, the specific installation and
maintenance requirements can be found in the thermal
flow switch instructions, which is attached with the unit.
water temperature sensor
If there is high accuracy requirement for water tempera-
ture control, the water temperature sensor can installed
at the distance of 5 time pipe diameter from water box.
Evaporator and Condenser Water
Piping
Figure 9 and Figure 10 illustrate the typical water piping
arrangements recommended for the evaporator and
condenser.
Note: Piping must be arranged and supported to avoid
stress on the equipment. It is strongly recom-
mended that the piping contractor refrain from
piping closer than 3 feet (0.91 m) minimum to the
equipment.This will allow for proper fit-up upon
arrival of the unit at the job site. Any adjustment
that is necessary can be made to the piping at
that time. Expenses that result from a failure to
follow this recommendation will not be paid by
Trane.
Water piping connection sizes are identified inTable 2,
p. 22,Table 3, p. 23, andTable 4, p. 23. Remem-
ber that with many waterboxes the entering and leav-
ing evaporator water can be piped to either water box
connection when the tube bundles are split vertically.
However, large evaporator waterboxes, with entering
and leaving connections not at the same level, must be
20 TCVHE-SVX04D-EN
Installation Water Piping
RELEASED 10/Mar/2020 06:59:20 GMT