Hitachi RAS-25QH1 Technische Information Seite 225

(2) How do LD305A and LD304B light?
(When LD304A and LD304B also light)
Blinks twice Blinks twice
Blinks twice Blinks once or
OFF
Blinks twice
F
Means communications are not possible between outdoor microcomputers.
(Microcomputer A aad Microcomputer B)
Check the outdoor microcomputers and interface circuit (PQ201A).
Means communications are not possible between outdoor microcomputers
(Microcomputer A a. Microcomputer B)
Check the outdoor microcomputers and interface circuit (PQ201B).
Blinks once or
OFF
NG
It is impossible from viewpoint of control (Microcomputer A 4 Microcomputer B)
Replace outdoor microcomputers.
Means communications are not possible with all indoor units.
: All indoor unit electrical parts are faulty
+ All indoor unit electrical parts are not connected.
- CN1A and CN1B are not connected.
: All interface (I/F) circuits are faulty
(I/F relays, I/F transformers, I/F-HICs, microcomputers)
Means communications are not possible with indoor units 1 and 2, but possible
with indoor units 3 and 4.
* Indoor unit 1 and 2 electrical parts are faulty.
+ Indoor unit 1 and 2 electrical parts are not connected.
* CN1A is not connected.
: I/F circuit for circuits A is faulty
(I/F relay, I/F transformer, I/F-HIC, microcomputer)
Means communications are not possible with indoor units 3 and 4, but possible
with indoor units 1 and 2.
- Indoor unit 3 and 4 electrical parts are faulty.
: Indoor unit 3 and 4 electrical parts are not connected.
- CN1B is not connected.
- VF circuit for circuit B is faulty
(I/F relay, I/F transformer, I/F-HIC, microcomputer)
Service switch can be operated
- Communications between outdoor microcomputers and with indoor urits are
normal.
* However, if indoor unit 1 or 2 does nor operate, check the I/F circuit for the unit
which does not operate.
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