Fujitsu ASTA09LCC Timer and Operation lights flash twice

[Graeme Chambers]

Hi all,

I have a Fujitsu ASTA09LCC where the timer and operations lights both flash twice together.

Does anyone have the error description for this please?

I've tested both internal thermistors and they check out ok (Correct resistance readings for the room temp).

I've also tried holding down the auto/manual button for five seconds and power cycling but it's made no difference.

Any help would be appreciated.

Thanks

Graeme

[Grizzly]

Hi Graham.
Welcome to the forum, there are others more familiar with these units than I.
However I have checked my fault lists and your sequence is not listed within what I have!
Hopefully someone can help further?
Good Luck Grizzly

[Tayters]

Hi Graeme,

This is a code for room probe open or short circuit. Strange if yours gives a reading then.

I've emailed you a chart of resistances to compare and a service manual. English version of the manual but should be similar for your system.
It would be worth checking if one of the lights carries on flashing (i.e. both flash twice together then another 5 flashes on the operation) to confirm the right fault code for starters.

If this is the right code then confirm resistance of the probe when unplugged. Next power up system and check for 5V DC across the 2 pins on the PCB.
If memory serves me correctly the probes are fixed directly on the PCB, not on a plug so you will need to check the voltage across them and compare on the chart or cut the wires and connect them back afterwards.

Common faults on these units are 7 and 2 flashes for discharge probe too hot (short of refrigerant) and 0 and 2 flashes for comms error - faulty outdoor PCB and/or compressor.

Hope that helps,

Andy.

[Graeme Chambers]

Thanks for the replies and thanks Andy for sending the manual and the chart.

I'd already cut the wires to the probe to test it so I'll just have to desolder the join and test the voltage from the board.

I'll try and find some time tonight once the kids go to bed to test the board.

The error code is definitely just two flashes on both lights at the same time and then no more after that.

Thanks again!

Cheers

Graeme

[Graeme Chambers]

Ok so I removed both thermistors and tested the leads going back to the board.

I got 5V on the lead for the thermistor attached to the pipework but didn't get 5V on the lead for the return air thermistor.

So it looks like there's a problem there.

On the weekend I'll remove the board and test the other discrete components that feed that 5V supply to see if one of them has shorted or become open.

Thanks for the help guys, looks like I'm getting somewhere now.

I'll keep you posted.

Cheers

Graeme

[Graeme Chambers]

Hi all,

Just an update on this one.

I tested the voltage at the board and it was 5V on both thermistors which was a bit confusing.

I then noticed some damage to the insulation of one of the wires.

It seems that a mouse had got in through the hole in the wall for the pipework and chewed part way through the thermistor cable!

A small section of replacement wire and a can of expanding foam later and life can return to normal!

Thanks to everyone for helping me get this fixed.

Cheers!

Graeme