Trane CXAJ series Installation, Operation And Maintenance Manual page 32

Unit Operation
The fault code is "98".
In the cooling mode, when the fin temperature of any system is lower than or equal to 58 ℃ , the
compressor of this system is allowed to run.
Ambient temperature over range protection (H Type Unit Only)
The ambient temperature range for the unit to reasonably run is 15 to 48 ℃ for cooling and -15
to 25 ℃ for heating. If beyond the range when starting, prohibit to start and report a fault code;
if beyond the range for 3 minutes after starting, automatically shut down and report a fault code.
The fault code is "87".
Automatic set heating temperature adjustment protection (H Type Unit Only)
In the heating mode, when the ambient temperature is lower than 0 ℃ , the set heating
temperature is set by the controller according to the following formula, and the user has no right
to set the water temperature:
a) When the ambient temperature is higher than or equal to -15 ℃ and lower than 0 ℃ , the set
heating temperature is equal to ambient temperature*0.667+50;
b) If the ambient temperature is lower than -15 ℃ , the set heating temperature is equal to 40 ℃ .
The set heating temperature is updated every 30 minutes according to the ambient temperature,
and is increased or reduced by 1 ℃ each time.
When the heating is started, if the ambient temperature is higher than or equal to 0 ℃ and the
set heating temperature is lower than 45 ℃ , the set heating temperature will be automatically
changed to the factory set value (45 ℃ ).
Flow protection
To avoid the evaporator freezing caused by the reduction of water flow, a flow switch (or other
flow sensing devices) shall be installed on the evaporator water pipe. Its set value must ensure
that the operation of compressor will be stopped immediately if the water volume is lower than
70% of the system design full flow.
Unit Operation (N Type)
Temperature sensor (TH1)
The temperature sensor (TH1) senses the water inlet temperature of the system as the basis for
compressor start or stop in the refrigeration and Heating modes.
Cooling mode:
Dual system
When the system is started, the water pump operates immediately. Two minutes later, the water
pump continues to operate. When the water return temperature is over 13 ℃ , No.1 compressor
will be started. One minute later, if the water return temperature is over 15 ℃ , No.2 compressor
will be started. If the cooling requirement is reached, the water return temperature will be
reduced to 11 ℃ , and No.1 compressor will be stopped. If the water return temperature is
continuously reduced to 10 ℃ , No.2 compressor will be stopped. Then, the load is increased, the
water return temperature rises to 13 ℃ , and No.1 compressor is restarted. If the water return
temperature continuously rises to 15 ℃ , No.2 compressor will run. Unless the unit is shut down,
the water pump will keep running.
32