- This topic has 2 replies, 2 voices, and was last updated 4 months, 4 weeks ago by
TheAChub.
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TheAChub
Hi all,
Have Fujitsu ducted unit. It was producing an error flash, but simply turned it off / on and it went away.
A couple of months later, the flash is back (reads as an E01 error – coms), and the reset doesn’t help.
Symptoms are fan mode works, cooling mode (fan runs, but no compressor – but its winter here now, so the compressor wouldn’t be required anyway), heating mode, nothing runs.
I contacted Fujitsu and they sent me the technical docs to test:
Only 20odd V on the outdoor signal wire (so outdoor unit com issue).
The Diode Bridge (all good at spec).
ACTPM (all good, except P/N connectors read as 710K- Should be 720 – 900, but surely 710K would be close enough)?
EEV (all good)
Fan motors (all good)
Compressor ( all good)Pulled both boards out. The power board looks perfect. Is it worth moving the varistor, and then putting back to the original position? Looks all good though.
The control board has all fuses ok. Did notice some very mild ‘off colour’ on the board around the JPZ transformer/ Q1 transistor/ zener diode/ R2/ R6 resistor, C1 cap area. The resistors look fine and measure to spec, the cap measured to spec, I pulled the transitor (Q1) and that was fine as well.So this thing has me stumped?? All the Fujitsu tests seem good, no fuses blown, and it was once fixed by simply reseting??
Any hints and tips would be greatly appreciated
Cheers
KingAC
In cases like this I used to run a new temporary comms cable between indoor/outdoor to see if the problem went away. Sometimes finding interrerence on a comms link can be difficult.
Dropping power on a Fujitsu clears the fault message as that are not stored long term.
TheAChub
Update.
I discovered the low voltage rails in the SMPS area were a mess. Diagnosed a few “iffy” electrolytic caps, then found pin 8 of the transformer was open circuit and the fall out from this was a dead Q1 transistor, ziener and normal diode along side that. Also, one of the fan motors had a shorted diode between the black and white pins. I repaired all of the above and fired it up without the fans plugged in. All the SMPS low voltage rails are now exactly what they should be on each test point. So plugged in everything except the dud fan motor. So Just connected the one that tests ok. However..when I fired it up the fan runs flat out straight away (regardless of what the control setting is set at), and the controller still has the E:EE error message.
Any ideas what could be causing this? Ive checked the Q801 /Q803 and associated diodes just before the fan output. All seem to test ok. Checked the green, blue, yellow, black, red thermistor plugs for any OLs. Have I missed anything? I also changed the fan over to fan 2 output. Exact same result. So something is making both fans run non stop?
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