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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.