Installation Electrical
RTAF-SVX001A-EN
27
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 Programmable Relay Option.
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 0.5 amp resistive.
The list of events/states that can be assigned to the
programmable relays can be found in
Table 12
. Chiller
events/Status description. The relay will be energized
when the event/state occurs.
Relay Assignments Using
Tracer TU
Tracer™ TU Service Tool 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. The relays to be programmed
are referred to by the relay’s terminal numbers on the LLID
board 1K23.
The default assignments for the four available relays of the
Programmable Relay option are:
If any of the Alarm/Status relays are used, provide
electrical power, 115 VAC 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. See the field
diagrams which are shipped with the unit.
Table 12.
Alarm and status relay output configuration
Description
Alarm - Latching
This output is true whenever there is any
active latching shutdown diagnostic that
targets the Unit, Circuit, or any of the
Compressors on a circuit.
Alarm - NonLatching
This output is true whenever there is any
active non-latching shutdown diagnostic that
targets the Unit, Circuit, or any of the
Compressors on a circuit.
Alarm
This output is true whenever there is any
active latching or non-latching shutdown
diagnostic that targets the Unit, Circuit, or
any of the Compressors on a circuit.
Alarm Ckt 1
This output is true whenever there is any
active latching or non-latching shutdown
diagnostic that targets Circuit 1, or any of the
Compressors on Circuit 1.
Alarm Ckt 2
This output is true whenever there is any
active latching or non-latching shutdown
diagnostic that targets Circuit 2, or any of the
Compressors on Circuit 2.
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.
Compressor Running
The output is true whenever any compressor
is running.
Circuit 1 Running
The output is true whenever any compressor
of Circuit 1 is running.
Circuit 2 Running
The output is true whenever any compressor
of Circuit 2 is running.
Ice Building
This output is true when Ice Building status is
active.
Maximum Capacity
The output is true whenever the unit has
reached maximum capacity continuously for
the Max Capacity Relay s time. The output is
false when the unit is not at maximum
capacity continuously for the filter time.
Evaporator Water
Freeze Avoidance
Request
This relay output is energized any time either
the Low Evaporator Water Temperature – Unit
Off or the Low Evaporator Temperature 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.
None:
This selection is desirable to provide an easy
way for a customer to defeat the effect of the
relay, if it has already been wired. For
instance, if the relay was normally
programmed as an “alarm” relay, and was
wired to a claxon, it may be desirable to
temporarily defeat the feature without
changing wiring.
Service request (for
Unit, Compressor(s) or
water pump):
This relay will be energized when at least one
Maintenance alert condition (refer to Service
required message specification) occurs, as
long as at least one of associated
informational diagnostic(s) will be active.
Table 13.
Default assignments
Relay
Relay 0
Terminals J2-1, 2, 3
Head Pressure
Relay 1
Terminals J2-4, 5, 6
Limit Mode
Relay 2
Terminals J2-7, 8, 9
Alarm
Relay 3
Terminals J2-10, 11, 12
Compressor Running
Table 12.
Alarm and status relay output configuration
Description
