Tech problem with Hitachi RAS-25/35

[Harvryo]

Help needed. I have not worked on AC since the 80's but I live in UK and have an apartment in France with a Hitachi RAS-25/35 which after 3 years good service has decided to cease cooling.
The timer lamp on indoor unit display blinks. The manual says to contact local sales agent but there is no one local who speaks English (my French is poor) and I would suspect it's a common fault.
I'm back in Uk now but would like to identify what parts to take with me next month when I drive down.
Can anyone help an overheated Brit?
Harvey.

[karim9]

hi harvryo

i am from france near paris and i think i can help u
if u like of of course
best regards

[Harvryo]

Hi Karim
Are you familiar with these units?

[al]

how many times is the lamp flashing, and is it a 25 or 35?

if its a recent vintage the fault codes are printed on the inside of the electrical cover on the outdoor unit.

al

[karim9]

no but if u have the book it will be easy

[Harvryo]

how many times is the lamp flashing, and is it a 25 or 35?

if its a recent vintage the fault codes are printed on the inside of the electrical cover on the outdoor unit.

al
Hi Al
I'm back in uk now and don't know if it's a 25 or 35 but the lamp flashes continuously at a rate of approx 60 per min.
The outdoor unit is on the roof of an apartment block and not easy to access so I was hoping someone may know what I should take with me when I visit next month or, if they have come across the problem previously, what the fault was.
Harv

[al]

14.3.6 RAS-18YH4, RAS-25YH4, RAS-35YH4, RAS-50YH4
TIMER LAMP DETAILS MAIN CHECK POINT
1 time: Reversing valve defective
When indoor heat exchanger temperature is too low in
heating mode, or it is too high in the cooling mode
1. Reversing valve defect
2. Heat exchanger thermistor disconnected ( only in
heating mode)
2 times: Outdoor unit forced operation
When the outdoor unit is in forced operation or balancing
operation after forced operation.
1. Electrical parts in the outdoor unit
3 times: Indoor/Outdoor unit interface defective
When the interface signal from the outdoor unit is
interrupted.
1. Indoor interface circuit
2. Outdoor interface circuit
9 times: Fault at room thermistor or heat
exchanger
When room thermistor or heat exchanger is opened circuit
or short circuit
1. Room thermistor
2. Heat exchanger thermistor
10 times: Over current at DC fan motor
When over current is detected at the DC fan motor of the
indoor unit
1. Fan motor locked
2. Indoor control P.W.B.
13 times: Data reading error
When data read from IC401 or IC402 is incorrect
1. IC401
2. IC402
NOTE:
If the interface circuit is faulty when power is supplied, the self-diagnosis display will not display.
Check the indoor unit F-cable if the indoor unit does not operate at all

copy of part of fault diagnosis on yh4 type unit, pm and i can send the full document, it's quite large though.

al

[al]

also need to know generation of indoor, ie yh4 or yh5 etc, there's two manuals and they appear to have differing fault codes.

missus fancies a holiday, we could fix it for you!!

al

[Harvryo]

14.3.6 RAS-18YH4, RAS-25YH4, RAS-35YH4, RAS-50YH4
TIMER LAMP DETAILS MAIN CHECK POINT
1 time: Reversing valve defective
When indoor heat exchanger temperature is too low in
heating mode, or it is too high in the cooling mode
1. Reversing valve defect
2. Heat exchanger thermistor disconnected ( only in
heating mode)
2 times: Outdoor unit forced operation
When the outdoor unit is in forced operation or balancing
operation after forced operation.
1. Electrical parts in the outdoor unit
3 times: Indoor/Outdoor unit interface defective
When the interface signal from the outdoor unit is
interrupted.
1. Indoor interface circuit
2. Outdoor interface circuit
9 times: Fault at room thermistor or heat
exchanger
When room thermistor or heat exchanger is opened circuit
or short circuit
1. Room thermistor
2. Heat exchanger thermistor
10 times: Over current at DC fan motor
When over current is detected at the DC fan motor of the
indoor unit
1. Fan motor locked
2. Indoor control P.W.B.
13 times: Data reading error
When data read from IC401 or IC402 is incorrect
1. IC401
2. IC402
NOTE:
If the interface circuit is faulty when power is supplied, the self-diagnosis display will not display.
Check the indoor unit F-cable if the indoor unit does not operate at all

copy of part of fault diagnosis on yh4 type unit, pm and i can send the full document, it's quite large though.

al
You are good!!! If you would email full doc to harvey4423@yahoo.co.uk I would really appreciate it. Then I can be sure of a fix first time.
Many thanks
Harv.

[al]

email sent, delete your address before you get inundated with spam. ;)

al