Evaporator Drain Flow Proving Devices - Trane RTWD Installation Operation & Maintenance

Evaporator Drain Flow Proving Devices

The installer must provide fl ow switches or differential
pressure switches with pump inter-locks to prove system
water fl ow. To provide chiller protection, install and wire
fl ow switches in series with the water pump interlocks,
for both chilled water and condenser water circuits
(refer to the Installation - Electrical section). Specifi c
connections and schematic wiring diagrams are shipped
with the unit.
Flow switches must prevent or stop compressor
operation if either system water fl ow drops off below
the required minimum shown on the pressure drop
curves. Follow the manufacturer's recommendations for
selection and installation procedures. General guidelines
for fl ow switch installation are outlined below.
CAUTION!
Evaporator Damage!
For all RTWD-RTUD units, chilled water pumps MUST
be controlled by the Trane CH530 to avoid catastrophic
damage to the evaporator due to freezing.
• Mount the switch upright on a horizontal portion of
water outlet pipe, with a minimum of 5 pipe diameters
run on each side of the switch.
• Do not install close to elbows, orifi ces or valves.
NOTE: The arrow on the switch must point in the
direction of the water fl ow.
• To prevent switch fl uttering, remove all air from the
water system
NOTE: The CH530 provides a 6-second time delay on
the fl ow switch input before shutting down the unit on
a loss-of-fl ow diagnostic. Contact a qualifi ed service
organization if nuisance machine shutdowns persist.
• Adjust the switch to open when water fl ow falls
below minimum. Refer to the General Data table for
minimum fl ow recommendations for specifi c water
pass arrangements. Flow switch contacts are closed
on proof of water fl ow.
Note: To prevent evaporator damage, do not use water
fl ow switch to cycle the system.
RLC-SVX14H-GB
Evaporator Piping
25