PACKAGED TERMINAL A/C
SERVICE MANUAL
Heat Controller, Inc.
13
Controller Functions and Operating Methods
The relationship between Centigrade and Fahrenheit is: Tcentigrade=Tfahrenheit*1.8+3.2
A. Temperature Parameter
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Indoor setting temperature (Tpeset)
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Indoor ambient temperature (Tamb)
B. System Basic Function
The compressor has a 3 minute time delay before it will start as a protective feature. Once the compressor begins to run, the
compressor cannot be stopped by changing the set temperature. However, it can be stopped by changing the mode the unit is
operating in or by turning the unit off. Once the unit is restarted, the compressor will not restart until the 3 minute time delay
has surpassed. (The compressor can be stopped immediately at the time of mode switchover, turning off the unit, adjusting set-
ting temperature and when in protective modes.)
1. Cooling Mode
When Tamb ≥2°F (1°C), the unit runs in cooling mode. Meanwhile, the compressor runs and the fan runs at the preset
fan speed.
When Tamb≤Tpreset-2°F (1°), the unit will turn OFF, the compressor will stop, however the fan will continue to run at the preset
fan speed;
When Tpreset-2°F (1°C)<Tamb<2°F (1°C), the unit keeps running with the previous settings.
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In this mode, the unit’s display will read the set temperature and the cooling LED is illuminated.
2. Fan Mode
In this mode, only the fan runs. The compressor won’t run and the temperature can’t be adjusted. The fan speed can be
changed. The display will read ambient temperature (32~99°F, when ambient temperature is higher than 99°F, it will display
H1; when ambient temperature is lower than 32°F, it will display L0), and the fan LED is illuminated.
3. Energy Saving Mode
When Tamb≥2°F (1°C), the unit runs in cooling mode. Meanwhile, the compressor runs and the fan runs at the preset
fan speed.
When Tamb≤Tpreset-2°F (1°C), the compressor will turn off while the fan will continue to run for 3 minutes; If Tamb≤Tpreset-
2°F (1°C), the fan will stop for 10 mins, and then turn on for 2 minutes at the preset speed. It will continue to cycle the fan on
and off in this sequence until Tamb≥2°F (1°C), then the fan and the compressor will start up (the start-up of compres-
sor will be delayed for 3 minutes; the fan start up will occur 30 seconds prior to the compressor).
4. Heating Mode
When Tamb≤Tpresent-2°F (1°C), the unit is runs in heating mode. Meanwhile, the electric heater will start after the fan
runs for 3 seconds. When Tamb≥T2°F (1°C), the electric heater will turn off and the fan will continue to run til Tair
exhaust≤90°F and the unit stops (the fan will run 15 seconds after the unit stops); Then the fan will stop for 10 minutes and
run for 1 minute at low fan speed. It will continue to cycle the fan on and off in this sequence until Tamb≤Tpreset-2°F (1°C).
5. OFF mode
If the OFF mode is selected the power button is active on the control panel. The freeze protection feature remains enabled, even
when the unit is OFF.
If the UP or DOWN buttons are pressed the display will turn off, after the ambient temperature is displayed for 15 seconds. The
indoor light will also turn off after 15 seconds.
6. Freeze Protection
This feature works in OFF, cooling and fan modes.
If the indoor ambient temperature is lower than 40°F (5°C) for 5 seconds, the electric heat mode and the freeze protection
mode will start up.
When the indoor ambient temperature is more than 50°F (10°C), the freeze protection mode will turn off.
After entering into the freeze protection mode, it can’t be stopped by pressing any buttons. During freeze protection mode, the
display reads “FP” and the green running LED is illuminated. During the freeze protection mode, the unit can’t be controlled by
the wall thermostat.
