Product data

58
thermostat must be provided to prevent
over-cooling an already cold room.
I. Controls and Safeties:
1. Electrical:
a. A control box shall be located within the unit
compressor compartment and shall contain a
50 va transformer, 24-volt activated, 2 or
3-pole compressor contactor, terminal block
for thermostat wiring and solid-state control-
ler for complete unit operation.
b. Reversing valve and fan motor wiring shall be
routed through this electronic controller.
c. Units shall be name-plated for use with time-
delay fuses or HACR circuit breakers. Unit
controls shall be 24-volt and provide heating
or cooling as required by the remote
thermostat/sensor.
2. Unit Controls:
a. Safety controls including a high-pressure
switch, a low-pressure sensor, and a low
water and low air temperature sensor. Access
fittings shall be factory installed on high and
low pressure refrigerant lines to facilitate field
service.
b. Activation of any safety device shall prevent
compressor operation via a microprocessor
lockout circuit. The lockout shall be reset at
the thermostat or at the contractor-supplied
disconnect switch.
c. Units which may be reset only at the discon-
nect switch only shall not be acceptable.
3. Complete C Controls:
The standard Complete C electronic control
system shall interface with a heat pump (Y,O)
wall thermostat (mechanical or electronic). The
control system microprocessor board shall be
specifically designed to protect against building
electrical system noise contamination, EMI, and
RFI interference. The control system shall have
the following features:
a. 50 va transformer.
b. Performance Monitor (PM). The PM warns
when the heat pump is running inefficiently.
c. Anti-short cycle time delay on compressor
operation time delay shall be 5 minutes
minimum.
d. Random start on power up mode.
e. Low voltage protection.
f. High voltage protection.
g. Unit shutdown on high or low refrigerant
pressures.
h. Unit shutdown on low water temperature.
i. Water coil freeze protection (selectable for
water or antifreeze).
j. Air coil freeze protection (check filter switch).
k. Condensate overflow shutdown.
l. Option to reset unit at thermostat or discon-
nect. Fault type shall be retained in memory if
reset at thermostat.
m. Automatic intelligent reset. Unit shall auto-
matically reset 5 minutes after trip if the fault
has cleared. Should a fault reoccur 3 times
sequentially, lockout requiring manual reset
will occur.
n. Ability to defeat time delays for servicing.
o. Light-emitting diodes (LED) to indicate high
pressure, low pressure, low voltage, high volt-
age, air/water freeze protection, condensate
overflow and control status.
p. The low-pressure switch SHALL NOT be
monitored for the first 90 seconds after a
compressor start command to prevent nui-
sance safety trips.
q. Remote fault type indication at thermostat.
r. Selectable 24-v or pilot duty dry contact
alarm output.
s. 24-v output to cycle a motorized water valve
with compressor contactor.
t. Electric heat output to control two stages of
electric heat (emergency heat).
u. Service test mode for troubleshooting and
service.
v. Unit Performance Sentinel (UPS). The UPS
warns when the heat pump is running
inefficiently.
Units not providing the 8 safety protections of
anti-short cycle, low voltage, high voltage, high
refrigerant pressure, low pressure (loss of
charge), air coil freeze, water coil freeze, and
condensate overflow protections will not be
accepted.
4. Deluxe D Controls:
Optional electronic Deluxe D control shall have
all the features of the Complete C control with
the following additional features:
a. 75 va transformer.
b. A removable thermostat connector.
c. Random start on return from night setback.
d. Intelligent reversing valve operation for
extended life and quiet operation.
e. Night setback control from low temperature
thermostat, with 2-hour override initiated by
a momentary signal from the thermostat.
f. Dry contact night setback output for digital
night setback thermostats.
g. Ability to work with heat/cool (Y, W)
thermostats.
h. Ability to work with heat pump thermostats
using O or B reversing valve control.
i. Single grounded wire to initiate night setback,
or emergency shutdown.
Guide specifications (cont)