Trane R Series Installation Operation & Maintenance page 38

38
Installation Electrical
Tab. IV-01 – Pump Relay Operation
Chiller Mode
Auto
Instant close Tracer Override
Stop
Ice Complete
Diagnostics
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 above
table) whereby the relay continues to be
energized occur with:
A Low Chilled Water Temp. diagnostic
(non-latching) (unless also accompanied
by an Evap Leaving Water Temperature
Sensor Diagnostic)
or
A starter contactor interrupt
diagnostic, in which a
continues to draw current even after
commanded to have shutdown
or
A Loss of Evaporator Water Flow
diagnostic (non-latching) and the unit is
in the AUTO mode, after initially having
proven evaporator water flow.
Relay Operation
Instant close Ice Building
Close
TImed Open
Instant Open
Instant Open
Alarm and Status Relay Outputs
(Programmable Relays)
A programmable relay concept provides
for enunciation of certain events or states
of the chiller, selected from a list of likely
needs, while only using four physical
output relays, as shown in the field wiring
diagram. The four relays are provided
(generally with a Quad Relay Output
LLID) as part of the Alarm Relay Output
Option. The relay's contacts are isolated
Form C (SPDT), suitable for use with
120 VAC circuits drawing up to 2.8 amps
inductive, 7.2 amps resistive, or 1/3 HP
and for 240 VAC circuits drawing up to
0.5 amp resistive.
The list of events/states that can be
assigned to the programmable relays
can be found in Table. The relay will be
energized when the event/state occurs.
failure
compressor
RTAC-SVX002A-EN