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Hitachi 00901 fault code

Hitachi air conditioning

What the Hitachi 00901 fault code means, from the manufacturer's own service literature, and the UK models it applies to.

What it means

Communication error (code 09)

Safety: Safe isolation before opening terminal covers — mains present on the interconnect.

Source: Hitachi Technical Catalogue §9.10 / §10.1.2 Error Code Information (RAK-PSES(W)/RAC-WSE — Hitachi UK; RAK-PED/RAC-WED — Hitachi R32 catalogue), both render-verified

UK models this code applies to

Tap yours to open 00901 on that machine.

Wall-mounted39
Cassettes28
Ducted24
Ceiling suspended7
Ceiling or floor8
Floor consoles3
Floor-standing8
Outdoor units61

00901 on these comes from each model's own manual, which may not match the meaning above — tap yours to read it.

Now the harder half: proving what caused it

00901 names a symptom, not a root cause. In the app, the same code opens a guided investigation: what to measure first, the expected values for your exact model, and an honest verdict — including “nothing in this machine is broken” when that's what the readings say.

Chase 00901 on your machine →

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