Installation and Maintenance Manual

Installation - Electrical
RLC-SVX09H-EN 107
Control Power Supply
The unit is equipped with a control power transformer; it
is not necessary to provide additional control power
voltage to the unit.
All units are factory-connected for appropriate labeled
voltages.
Interconnecting Wiring
Chilled Water Flow (Pump) Interlock
If paddle option is selected, RTWD/RTUD Series R
®
chillers
require a field-supplied control voltage contact input
through a flow proving switch 5S5 and an auxiliary contact
5K9AUX. Connect the proving switch and auxiliary contact
to 1A15 J3-1 and 1X4-1. Refer to the field wiring for details.
The auxiliary contact can be BAS signal, starter contactor
auxiliary, or any signal which indicates the pump is
running. A flow switch is still required and cannot be
omitted.
Condenser Water Flow Interlock
If paddle option is selected, RTWD Series R
®
chillers
require a field-supplied control voltage contact input
through a flow proving switch 5S6 and an auxiliary contact
5K10 AUX. Connect the proving switch and auxiliary
contact to 1A15 J2-1 and 1X4-1. Refer to the field wiring for
details.The auxiliary contact can be BAS signal, starter
contactor auxiliary, or any signal which indicates the pump
is running. A flow switch is still required and cannot be
omitted.
Chilled Water Pump Control
An evaporator water pump output relay closes when the
chiller is given a signal to go into the Auto mode of
operation from any source.The contact is opened to turn
off the pump in the event of most machine level
diagnostics to prevent the build up of pump heat.
The relay output from board 1A14 is required to operate
the Evaporator Water Pump (EWP) contactor. Contacts
should be compatible with 115/240VAC control circuit.The
EWP relay operates in different modes depending on
CH530 orTracer commands, if available, or service
pumpdown (See maintenance section). Normally, the
EWP relay follows the AUTO mode of the chiller.Whenever
the chiller has no diagnostics and is in the AUTO mode,
regardless of where the auto command is coming from,
the normally open relay is energized. When the chiller
exits the AUTO mode, the relay is timed open for an
adjustable (usingTechView) 0 to 30 minutes.The non-
AUTO modes in which the pump is stopped, include Reset
(88), Stop (00), External Stop (100), Remote Display Stop
(600), Stopped byTracer (300), Low Ambient Run Inhibit
(200), and Ice Building complete (101).
Regardless of whether the chiller is allowed to control the
pump on a full-time basis, if the MP calls for a pump to start
and water does not flow, the evaporator may be damaged
catastrophically. It is the responsibility of the installing
contractor and/or the customer to ensure that a pump will
start when called upon by the chiller controls.
Note: Exceptions are listed below.
When going from Stop to Auto, the EWP relay is energized
immediately. If evaporator water flow is not established in
4 minutes and 15 sec., the CH530 de-energizes the EWP
relay and generates a non-latching diagnostic. If flow
returns (e.g. someone else is controlling the pump), the
diagnostic is cleared, the EWP is re-energized, and normal
control resumed.
If evaporator water flow is lost once it had been
established, the EWP relay remains energized and a non-
latching diagnostic is generated. If flow returns, the
diagnostic is cleared and the chiller returns to normal
operation.
In general, when there is either a non-latching or latching
diagnostic, the EWP relay is turned off as though there was
a zero time delay. Exceptions (see Table 90) whereby the
relay continues to be energized occur with:
A Low Chilled WaterTemp. diagnostic (non-latching)
(unless also accompanied by an Evap Leaving Water
Temperature Sensor Diagnostic)
OR
A starter contactor interrupt failure diagnostic, in which a
compressor continues to draw current even after
commanded to have shutdown
OR
A Loss of EvaporatorWater Flow diagnostic (non-latching)
and the unit is in the AUTO mode, after initially having
proven evaporator water flow.
NOTICE:
Evaporator Damage!
All RTUD units (systems with a remote condenser)
REQUIRE chilled water pumps be controlled by the
Trane CH530 to avoid catastrophic damage to the
evaporator due to freezing. It is strongly recommended
that chilled water pump control also be used on RTWD
to provide proper unit operation.
Table 90. Pump Relay Operation
Chiller Mode Relay Operation
Auto Instant close
Ice Building Instant close
Tracer Override Close
Stop Timed Open
Ice Complete Instant Open
Diagnostics Instant Open