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Chapter 4 Applications for the heat pump configuration
20
SET: Local set point
The SET analog input functions as the local (hardwired) temperature set-
point input for applications utilizing a Trane zone sensor with a tempera-
ture set-point thumbwheel. The ability to enable or disable the local set-
point input is available in the Rover service tool. A communicated set-
point value can also be used for controllers operating on a BAS. When
both a hardwired and communicated set-point value is present, the con-
troller uses the communicated value. When neither a hardwired nor a
communicated set-point value is present, the controller uses the stored
default set points (configurable in Rover). If a valid hardwired or commu-
nicated set-point value is established and then is no longer present, the
controller generates a Setpoint Failure diagnostic.
FAN: Fan mode input
The FAN analog input functions as the local (hardwired) fan mode switch
input for applications utilizing the Trane zone sensor with a fan mode
switch option. Valid fan modes for a heat pump are off and auto. The abil-
ity to enable or disable the local fan mode input is available in the Rover
service tool. A communicated fan mode request can also be used for con-
trollers operating on a BAS. When both a hardwired and communicated
fan mode value is present, the controller uses the communicated value.
When neither a hardwired nor a communicated fan mode value is
present, the controller recognizes the fan mode value as auto and oper-
ates according to the default configuration. If a valid hardwired or com-
municated fan mode value is established and then is no longer present,
the controller generates a Fan Mode Failure diagnostic.
AI1: Leaving water temperature
Note:
Neither AI1 nor AI2 is polarity sensitive; you can connect either
terminal to either sensor lead.
The AI1 analog input functions as the local (hardwired) leaving water
temperature input. The controller will not accept a BAS-communicated
leaving water temperature value. The leaving water temperature is used
to protect the heat exchanger from freezing. The controller compares the
leaving water temperature to the Leaving Water Temperature Cutout
Setpoint, which is configurable in Rover (default of 35°). When the leav-
ing water temperature falls below the cutout set point, the controller gen-
erates a Low Temp Detection Circuit 1 diagnostic. When a valid leaving
water temperature is not present, the controller generates a Leaving
Water Temp Failure diagnostic.
BI1 is used to protect the second heat exchanger from freezing in a two-
compressor unit (see "BI1: Low-temperature detection (circuit 2)" on
page 14).
CNT-SVX06B-EN
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