Troubleshooting
- 101 -
is required.
2. Electrics and control protections and functions for FR23-B, FRD35-B, FRD50-B, FR(D)95,
FR(D)125/S, FR(D)71-B and FR(D)100-B
A. Unit control objectives
a. Indoor fan (one for all models except FR(D)100-B, which has two 3-speed fans)
b. Outdoor fan (one for all models; 1-speed for FR23-B, FRD35-B, FRD50-B, 2-speed for
others)
c. Compressor
d. Reversing valve
e. Indoor PTC auxiliary electric heater
B. Electrics and control troubleshooting
Failure Phenomena Failure analysis
3 occurrences of
anti-freeze
protection
When 3 consecutive such
protection signals are detected in
1h, AC unit stops, wire controller
displays E1, you can only put it
into operation after re-powerup
Check for normal cooling system; check for bad
contact at ID pipe temperature sensor connection;
check for broken wire or short circuit at sensor; if
normal, check if R6 on indoor board is 10K
ID ambient temp
probe broken wire
(short circuit)
Wire controller displays E2, put
it into operation after re-powerup
First check ID ambient temperature sensor
connection for bad contact, check for broken wire or
short circuit in sensor; if normal, check if R7 on ID
board is 10K
ID pipe temp
probe broken wire
(short circuit)
Wire controller displays E3, put
it into operation after re-powerup
First check ID pipe temperature sensor connection
for bad contact, check for broken wire or short circuit
in sensor; if normal, check if R6 on ID board is 10K
OD pipe temp
probe broken wire
(short circuit)
Wire controller displays E4, put
it into operation after re-powerup
First check OD pipe temperature sensor connection
for bad contact, check for broken wire or short circuit
in sensor; if normal, check if R5 on ID board is 10K
Communication
failure
In case of communication failure
etween main control board and
wire controller, the latter displays
E5, and you can only put it into
operation after re-powerup
Check for reliable welding on main control board CN6
and wire controller CN1 needle seat, reliable insertion
of cards and broken or short circuit of communication
line;
Check for DC12V input on wire controller, DC5V
output on main control board 7805-3 pin, and DC5V
on RG1-3 of wire controller;
Check normal voltage on main control board 2003
driving block;
Check for normal voltage on crystal oscillator pin of
main control board and wire controller;
Check for normal voltage at communication input/output
of main control board and wire controller
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