39
OPERATIONS
• Indoor/Outdoor Coil Thermistors-
In the cooling mode,
if the compressor is engaged continuously for 20 min-
utes and the Indoor Coil Thermistor is below 30 de-
grees the compressor is disengaged until the ICT rises
above 45 degrees. The Outdoor Coil Thermistor senses
coil temperature which correlates to outdoor air tem-
perature. Heat pump operation can operate as low as
24°F outdoor temperature depending upon humidity con-
ditions and/or the balance point of the system. After
defrost is initiated, the compressor remains off for at
least thirty minutes and resumes operation when the
outdoor coil temperature reaches 33°F. Electric resis-
tance heat will maintain the ambient room tempera-
ture anytime the temperature falls 4°F below the room
set point temperature.
• Load Shedding-
The LS & IN terminals are used for load
shedding. A switch can be added to close the circuit to
lock out the compressor and electric heat when the power
company or energy management system is trying to re-
duce its load for a specified time.
• Sample Before Start -
The SBS routine is used in the
cooling mode. This routine runs the unit fan on low speed
for up to 120 seconds. The sample fan is aborted if
compressor demand is detected. To avoid unnecessary
sampling the period between samples will be based on
specific room conditions. The default sample before
start period after a power up is 5 minutes. The period
is corrected every time a sample run is completed with-
out a compressor demand. The minimum sample pe-
riod is 5 minutes and the maximum period is 15 min-
utes.
• Remote Temperature Sensor -
An auxiliary tempera-
ture sensor ( RTS02) may be connected to the control
that senses actual room temperature. This sensor re-
places the Indoor Ambient Thermistor and will connect
to the Indoor Air terminals on the control.
• Front Desk Control -
The front desk control terminals
are FD1 and FD2. These terminals will provide a con-
nection for a user supplied switch that will allow the
operation of the unit to be remotely defeated.
• Transfer Fan-
A transfer fan may be used if a user
supplied relay is connected to TF1 and TF2. Make sure
the relay is a manufactured approved relay. The relay
will be energized whenever the blower/fan relay is en-
ergized.
• Emergency Hydronic Heat -
A switch can be added to
the EH & IN terminals to close the circuit to enable the
fan, enable the heater relay and lockout the compres-
sor to continue minimum operations with auxiliary
power, if the main power goes out.
DIGITAL BOARD DIAGNOSTICS
If a failure is detected on the digital board, there will be a
green light constantly lit up. This light is located under the
OFF touch pad button. The board will need to be programed
into the Diagnostic Maintenance & Status Report mode to
determine the failure and the procedures to correct the fail-
ure.
DIAGNOSTIC MAINTENANCE & STATUS REPORT
To enter
Diagnostic Status Report mode,
press and hold
the up and down
arrows and, while holding, quickly
press the COOL key
twice.
Active Failures.
• If there are no active failures or lockouts, the display
will show a double dash, “- -”. If there is a code listed,
see the unit “Diagnostic Codes” chart for a list of defi-
nitions.
Operating Temperatures.
• If not in Diagnostic Status Report Mode, enter as in-
structed above and press the Fan Speed
key.
• If already in Diagnostic Status Report mode, press the
Fan Speed
key. The display will show the tem-
perature of the desired set point,
SP
; the temperature
at the wireless thermostat,
rL
; the indoor ambient tem-
perature behind the filter,
IA
; the indoor coil tempera-
ture,
IC
; the indoor discharge air temperature,
Id
; the
outdoor coil temperature,
OC
; the outdoor ambient tem-
perature,
OA
; and the spare probe temperature,
IH
. If
any of the probes are not populated, the display will
show the corresponding failure code.
Past Failure Log
• If not in Diagnostic Status Report Mode, enter as in-
structed above and press the Fan Speed
key twice.
• If already in Diagnostic Status Report mode, press the
Fan Speed
key. While the display is showing op-
erating temperatures, the last 10 failure codes active
or past can be requested by pressing the Fan Speed
key again. The codes are displayed last entry
first followed subsequently by each preceding code.
Note that modes and
are also displayed in
the normal control operation (see “Diagnostic
Codes” chart).
F1
Fd
To exit
Diagnostic Status Report mode,
press
the OFF
key.
