Example Of Checking - Hitachi RAF-25NH4 Service Manual

<Example of checking>
※ Explaining an example of checking for table. 2- 1
(A) : Communication error 1 (LD 303A or LD 303B one time blink)
In the case of the indoor unit 1 (or 3) is in the communication error and the indoor unit 2 (or 4) is normal: At first, check the
connections of the in/outdoor connecting cables in the indoor and outdoor units (wrong connection, poor insertion etc).
If being normal state, unplug the power supply (turn off the overcurrent breaker), and remove the in/outdoor connecting
cable, then insert the right cable (connected on C2C3 (C4, D4) terminals) into C1D1 (C3, D3) terminals and turn on the
power supply (overcurrent breaker). (Connect no cable to C2C3 (C4, D4) terminals.)
If the electric parts of the outdoor unit are normal, Ò
C2D2 (C4, D4) terminals), but ÒLD303A (LD303B) blinks three times," the control P.W.B. of the outdoor unit may
malfunction.
※ When replacing C1D1 with C2D2 (C3D3,C4D4), take care of connecting normally, in the case of connecting in reverse,
LD303A will blink 3 times and the outlet (35V) fells down to 5V or less (protector operated).
※ When replacing C1D1 with C2D2 (C3D3, C4D4), unplug the power supply (turn off the overcurrent breaker) or the P.W.B.
will be damaged.
※ After checking, put back the parts in proper state.
(B) : Communication error 2 (LD303A or LD303B blinks two times)
In the case of the indoor units 2 (or 4) is in the communication error and the indoor unit 1 (or 3) is normal:
As above-mentioned (A), check the connections of the in/outdoor connecting cable in the indoor and outdoor units (wrong
connection, poor insertion, etc).
If being normal state, unplug the power supply (turn off the overcurrent breaker ) and remove the cables , then insert the
cable connected on C1D1 (C3, D3) into C2D2, and turn on the power supply (overcurrent breaker). (Connect no cable to
C1D1 (C3, D3).) If the electric parts of the outdoor unit are normal, ÒLD 303A (LD 303B) may blink one timeÓ (because of
no connection to C1D1 (C3, D3) terminals.), but ÒLD 303A(LD 303B) blinks 3 timesÓ, the control P.W.B. of the outdoor unit
may malfunction.
※ Measure a voltage of the 35V-outlet, and take care of connecting in proper state.
(C) : Communication error 3 (LD 303A or LD 303B blinks three times)
In the case of that both the indoor unit 1 and 2 (the indoor unit 3 and 4) are in the communication error: At first, check the
connections of ÒCD reverseÓ in the indoor and outdoor units, oK or not. If one line of either C1D1 or C2D2 terminals is
connected wrongly in CD reverse, ÒLD 303A blinks three timesÓ. Similarly, If one line of either C3D3 or C4D4 is connected
wrongly in CD reverse, ÒLD 303B blinks three timesÓ.
※ If CD is connected in reverse , the outlet (35V) fells down to 5V or less (protector operated).
In the case of connecting CD in no reverse, check the voltage between C1D1 and C2D2 (C3D3, C4D4) terminals by the
tester. If the voltage is in abnormal , turn off the power supply for a moment, and check the voltage again after removing
C1D1 and C2D2 (C3D3, C4D4). but the checked voltage is normal at this time, the indoor unit 1 or 2, or both (unit 3 or 4,
or both) malfunction.
For the purpose of determining the units malfunctioned, connect the units one by one and check them at each time. If the
35V outlet is abnormal after removing C1D1 and C2D2 (C3D3, C4D4), "SW-D-P.W.B" is defective. If the 35V outlet is
normal, measure the voltages between C1 D1, C2 D2, (C3 D3, C4 D4) each terminal by the indicated tester (with 1V full
scale and AC sampling range).
In this just case of indicating the communication error of LD 303A or LD 303B, when the indicator is moving slightly , the
HIC of the outdoor unit control P.W.B may be malfunction. (The electric parts of indoor unit are probably not defective
because the indoor unit has not short circuit and two of the indoors interface circuit may be not malfunction at same time)
If the indicator does not move at all, the outdoors interface circuit is malfunction.
Remove and insert the connectors, cables and others, after disconnecting the power cord plug from the power
※
supply outlet.
※ Be aware that the outdoors electric parts, the switching power supply in particular may be defective at leaving CD connection
in reverse.
D 303A ( D303B) blinks two times
208
Ó (because of no connection to