7
CNT-SVU006A-GB
4 programmable relays are provided 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 relays 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 0.5amp resistive.
The list of events/states that can be assigned to the programmable relays can be found inTable (…) Chiller events/
Status description.The relay will be energized when the event/state occurs.
Depending of the unit type and option, the list of function behind programmable can vary.
Tracer™TU ServiceTool is used to install the Programmable Relay Option package and assign any of the above lists
of events or status to each of the four relays provided with the option. (See “Tracer™TU,” for more information on
theTracerTU service tool)
If any of the Alarm/Status relays are used, provide electrical power, 115VAC with fused-disconnect to the panel
and wire through the appropriate relays (terminals on 1A10). Provide wiring (switched hot, neutral, and ground
connections) to the remote annunciation devices. Do not use power from the chiller’s control panel transformer to
power these remote devices. Refer to the field diagrams which are shipped with the unit.
Table 2 –
Programmable relay event/status descriptions
Relay function Description
Alarm This output is true whenever there is any active latching or non-latching shutdown diagnostic that targets the
chiller, circuit, or any of the compressors on a circuit.
Alarm - Latching This output is true whenever there is an active latching shutdown diagnostic that targets the chiller, circuit,
or any of the compressors on a circuit.
Alarm - NonLatching This output is true whenever there is an active non-latching shutdown diagnostic that targets the chiller,
circuit, or any of the compressors on a circuit.
Alarm Ckt X This output is true whenever there is any active latching or non-latching shutdown diagnostic that targets
Circuit X, or any of the Compressors on Circuit X.The CMAF design have 2 circuits.
Alarm – General Latching Ckt X
This output is true whenever is latching alarm(s) that targets circuit X or all the compressors on circuit X
so that the circuit X is unable to produce any capacity. It mean it activates when there is latching alarm on
circuit, or latching alarms on every compressor of circuit.
Alarm – General Latching Unit
This output is true whenever is latching alarm(s) that targets chiller or all circuits or all the compressors on a
circuit so that the unit is unable to produce any capacity. It means it activates when there is latching alarm on
Chiller, or ‘General Latching Circuit X’ on every circuit.
Alarm – General Non Latching Ckt X This output is true whenever is non latching alarm(s) that targets circuit X or the compressors on circuit X so
that the circuit X is unable to produce any capacity.
Alarm – General Non Latching Unit
This output is true whenever is at least a non latching alarm(s) that targets chiller or circuits or compressors
on a circuit and there are latching or/and non latching diagnostics that targets chiller, circuits or compressors
so that the unit is unable to produce any capacity.
Unit Limit Mode
This output is true whenever a circuit on the unit has been running in one of the limit modes continuously
for the Limit Relay debounce time. A given limit or overlapping of different limits must be in effect
continuously for the debounce time prior to the output becoming true. It will become false if no limits are
present for the debounce time.
Circuit X Running The output is true whenever any compressor of Circuit X is running.The CMAF design have 2 circuits.
Compressor Running The output is true if any compressor on the unit is running.
Cooling
The output is true if capacity control is in Chilled Water Control mode (the water temperature is being
controlled to the Active Chilled Water Setpoint).This output is active when running in Cooling only or Heat
Recovery.
Heating
The output is true if capacity control is in Hot Water Control mode (the water temperature is being controlled
to the Active Hot Water Setpoint). It includes Air source heat pump operation of heat recovery operation.The
output is false in any other capacity control mode (Cooling Air Cooled, etc.).This output is true if it is running
in Heat Recovery or Air-Source Heat Pump (Heating).
Evaporator Water Freeze Avoidance
Request
This relay output is energized any time either the Low Evaporator WaterTemperature – Unit Off or the
Low EvaporatorTemperature Ckt x – Unit Off diagnostics are active. This relay is intended for use as an
external interlock for a field engineered and provided solution to mitigate the freeze danger implied by
these diagnostics. Generally, this would be used in cases where operation of the evaporator water pump is
unacceptable due to the system constraints, (i.e. such as mixing unconditioned warm water with controlled
supply water as provided by other parallel chillers).The relay’s output can provide the method to close
bypass valves so the circulation becomes local to the evap and excludes the load, or can be used to defeat
the evap pump override entirely while initiating an independent source of heat / flow to the evap.
Heat Recovery / Condenser Water
Freeze Avoidance Request
The relay output is energized any time either the Low Condenser WaterTemperature – Unit Off or the Low
CondenserTemperature Ckt X – Unit Off diagnostics are active. The intent is to notify the customer during
conditions of freeze risk for the condenser when the unit is off.
Programmable Relays
