15
Compressor Preheating Function
The compressor crankcase heater will activate if:
— The outdoor am bient tem perature, T4, i s low er tha n 37_F
(3_C) and power has been recently suppli ed to the machine.
—IfT4<37_F(3_C) and the compressor has not been
operating for over 3 hours.
During the preheating mode, a weak current flow flows through
the compressor coil from the wiring terminal of the compressor.
The compressor is heated when this is not operating.
The preheating function will deactivate if T4 is greater than 41_F
(5_C) or the compressor starts operating.
Condenser temperature protection
The condenser temperature protection function acts as follows:
— If the condenser coil temperature (T3) is between 131_F
and 140_F (55C_<T3<60_C), the compressor frequency
will decrease to a lower level until it reaches the lowest
value, F1. It then runs at this F1 frequency. Once
T3<129_F(54_C), the compressor will continue running
at the current frequency.
— When the coil temperature reaches a value lower than
126_F(52_C), the compressor will not limit the
frequency and resumes to the required frequency.
— If T3>140_F(60_C) for 5 seconds, the compressor will
stop and restart once the coil temperature reaches a value
lower than 126_F(52_C).
Evaporator Temperature Protection
The evaporator temperature protection function acts as follows:
— If the evaporator coil temperature (T2) is lower than
32_F(0_C), the compressor will stop and restarts once
T2 ≥ 41_F(5_C).
—If32_F ≤ T2 <39_F(0_C ≤T2 <4_C), the compressor
frequency will be limited and decreased to a lower level.
—Now,if39_F ≤T2 <45_F(4_C ≤T2 <7_C), the
compressor continue running at the current frequency.
— If T2>45_F(7_C), the compressor frequency will not be
limited, and operation is normal.
SEQUENCE OF OPERATION
Interface
A wireless remote control, supplied with the unit, is the interface
between the fan coil and the user . The wireless remote control has
the following characteristics:
S Capable of dis pl aying _Cand_F with _F being the default
setting. To cha nge the default se tti ng, re fer to the Owner’s
Ma nual.
S The remote control setpoint range is from 62_F(17_C) to
86_F(30_C) in increments of 1_F(1_C).
S The wireless remote control has an operating range of 25 ft.
(7.62 m).
S The same remote control can be used to control more than one
unit.
S If the remote control is lost, damaged, or the batteries are
exhausted, the system can be operated by using the manual
button (forced Auto) located under the front panel.
Manual Button
AUTO/COOL
Fig. 18 – Manual Button Location on Unit
MODES OF OPERATION
COOLING MODE
In this mode, the system cools and dries the room air with the fan
running continuously, either at a selected fan speed or Auto fan
speed. The fan runs even when the compressor cycles off. This
feature enhances room comfort and efficiency of the system.
Compressor operation in cooling
mode:
In cooling mode, the maximum operation frequency (Fmax) of the
compressor, after it starts running, depends on the outdoor ambient
temperature (T4).
Onc e the system starts running, the com pressor will run at the Fma x
frequenc y f or 7 minutes at a s pecific T4. Dur ing t his time, the
frequency limitation is active, therefore the compressor will continue
running eve n i f the s et poi nt condition is satisfied. The compressor
running fr equency wil l the n be controlled bas ed on t he difference
betwe en the room temper atur e and the te m perature set point (T1- Ts).
Outdoor Fan Operation in Cooling
Mode:
When in cooling mode, the outdoor fan motor cycles based on the
outdoor ambient temperature as shown below:
Fig. 19 – Cooling mode
Indoor Fan Operation in Cooling
Mode:
When in cooling mode, the indoor fan runs continuously either at
the chosen set speed (high, medium, or low), or in Auto mode,
where the speed is determined by the microprocessor based on the
difference between the room temperature and the temperature set
point as shown below:
Fig. 20 – Cooling mode
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