Overheating Protection For Indoor Unit
The indoor coil sensor senses the temperature of the indoor
coil.
If the temperature sensed is greater than 133°F, the com-
pressor frequency will decrease to prevent overheating of
the heat exchanger.
If Tc >= 133°F for more than 10 seconds, the compressor will
HSU129HG(DB)-SM
stop and an error code will be indicated at the outdoor unit.
5.2.5.2 TC high temperature-preventing control of the indoor heating unit
If the compressor is off for 3 minutes and Tc <118°F, the com-
Tpg_indoor is the highest value of the effective indoor unit (start it and it is in accord with the running
state).
pressor will restart.
The indoor heat exchanger sensor tests the temperature of the indoor heat exchanger. If the
If the temperature sensed is lower than 118°F, the protection
temperature is higher than 55 , decrease the rotate speed of the compressor and do the high
function is cancelled.
temperature-preventing protection of the indoor heat exchanger; if the temperature of the indoor heat
exchanger is lower than 47 , recover to the normal control.
TC
Fgh_t1 2
Fgh_t2 2
Fgh_t3 2
Fgh_t4—2
Fgh_t5—2
Normal
N Decreasing at the speed of 1HZ/1 second
P Decreasing at the speed of 1Hz/10 seconds
Q Continue to keep the last-time instruction cycle
R Increasing at the speed of 1Hz/10seconds
Remarks: the outdoor unit
5.2.5.3 The control of preventing the overcurrent of the compressor
Compressor Overcurrent Protection
During the starting process of the compressor, if the curren of the compressor is greater than 17A
for 3 seconds, stop the compressor and alarm, after 3 minutes, start it again, if such state appears 3
If the current draw of the compressor at start-up is greater
times in 20 minutes, stop the compressor and alarm, and confirm the malfunction. Then continue to
than the overcurrent point listed on the chart below for ap-
run it only after the the power is off.
proximately 3 seconds, the compressor will stop, and a code
During the starting process of the compressor, if the AC current is greater than 12A, the frequency
of the compressor decreases at the speed of 1HZ/second.
will be indicated at the outdoor unit. After 3 minutes the
During the starting process of the compressor, if the AC current is greater than 10A, the frequency
compressor will try to restart. If the overcurrent condition
of the compressor decreases at the speed of 0.1HZ/second.
occurs 3 times in 20 minutes, the system will lock-out, and a
During the starting process of the compressor, if the AC current is greater than 9A, the frequency of
the compressor increases at the prohibited speed.
code will be indicated at the outdoor unit. It will be necessary
During the starting process of the compressor, if the AC current is greater than 8A, the frequency of
to remove power to the system to reset the lock-out condi-
the compressor increases at the speed of no faster than 0.1HZ/second.
tion.
The frequency of the compressor may change depending on
the current draw at start-up. Refer to the chart and current/
Hz table shown below.
Greater than current 1: Decreases 1Hz/second
Greater than current 2: Decreases 0.1Hz/second
Greater than current 3: No change
Over
Current
Model
Point
(Approx.)
09K
11A
12K
13A
15K
15A
18K
15A
24K
17A
Wiring Diagrams
The compressor stops
Fgh_t1 65
N Decreasing the frequency rapidly
Fgh_t2 59
P Decreasing the frequency slowly
Fgh_t3
Q Prohibiting increasing the frequency Fgh_t4
R Increasing slowly
Fgh_t5
25
Domestic Air Conditioner
Decline
Decline
Speed
Speed
Current 1
Current 2
Current 3
(Approx.)
(Approx.)
(Approx.)
8.5A
8A
10A
9.5A
12A
11.5A
12A
11.5A
13.5A
13A
SEQUENCE OF OPERATION
Anti-Freeze Protection of the Indoor Coil
The temperature sensed by the indoor unit coil sensor is used
to determine what frequency the compressor is to run at for
freeze protection.
Tpg_indoor: indoor unit pipe sensor temperature
When Tpg_indoor < Tpg1, the frequency of the compressor
decreases at the rate of 1HZ / 1 second.
When Tpg_indoor < Tpg2, the frequency of the compressor
decreases at the rate of 10HZ / 10 seconds.
When Tpg_indoor begins to rise again, and Tpg2 ≤ Tpg_indoor
≤ Tpg3, the frequency of the compressor does not change.
When Tpg3 < Tpg_indoor <Tpg4, the frequency of the com-
pressor increases at the rate of 1HZ / 10 seconds.
149°F
Example: if Tpg_indoor ≤ 32°F sustains for 2 minutes, the
138°F
outdoor unit will stop and indicate an underload malfunction
131°F
55
code at the outdoor unit. The compressor stops for a mini-
124°F
51
mum of 3 minutes. When Tpg_indoor >Tpg4, the compressor
117°F
47
will restart.
48°F
43°F
41°F
37°F
32°F
Anti-Freeze Protection of the Base Pan
To prevent freezing; the base pan equipped with electrical
heater. Its operational conditions are as follows:
If outdoor temperature is above 37.4°F, the electrical base
pan heater is off.
Between 24.8°F and 33.8°F outdoor temperature; the elec-
trical base pan heater is off for 20 minutes, then on for 10
minutes.
Between 10.4°F and 24.8°F; the electrical base pan heater is
off for 15 minutes, then on for 15 minutes. If outdoor tem-
perature <10.4°F, the electrical base pan heater is on.
Decline
Speed
7A
8.5A
10.5A
10.5A
12A
59°F // ice_temp_3+5
Increasing slowly
46°F // ice_temp_3+2
Keeping the frequency
43°F
Decreasing slowly
Decreasing rapidly ice_temp_1
Stop
PAGE 27