Zanussi ZX99/5SI – freezer not defrosting

[bob.smith]

** UPDATED **
Hi,

i’ve had this zanussi ZX99/5SI for 2.5 yrs now. and its been great.

Until now. Last week the fridge was warm while the freezer was fine, i stumbled into these forums via Google, and found that i should defrost. I did this and it seemed to cure the problem (in fact it was working better than ever). However yesterday it had stopped again. Its now giving three flashing lights and a warning beep, intermittently. I removed the two screws in the top of the freezer and pulled the evaporating coil unit forward, it was thick with soft frost.

Questions:
1. Where is the heater coil on this thing so i can check if it is open circuit?
2. Is this likely to be board related? if so is it the one the left of the rear panel (compressor compartment)?
3. Is this a common fault with this model?
4. How much am i looking at for new heater or pcb?

quick notes:
compressor is not running all the time
fan is running

UPDATE
unit was fully defrosted, no ice nor water anywhere on the evaporator coil.
restarted it, and the compressor kicks in after about 30 seconds or so, and continues to run for about 20mins, at which point i hear a single short beep (more like a chirp), i checked the indicator lamps, and only power was lit. the compressor shuts down for about 30 seconds, then starts up again. But it is working.
I left it to run for 12 hours, and i can see frost on the front of the evaporator.
So does that single chirp mean that the things knows something is wrong, are there any codes for this unit?

Very many thanks,

BOB.SMITH

edited: no z in zanussi doh!

[Del]

Re: Zanussi ZX99/5SI – freezer not defrosting

It could be a few things, but first of all just for clarification the ice forms on the evaporator not the condenser. It could be :-

1) The defrost stat open circuit
2) The defrost elements open circuit
3) The control pcb not initiating the defrost cycle

Remember power off, before all else !!!

Del

[bob.smith]

Re: Zanussi ZX99/5SI – freezer not defrosting

Hi Del

Doh, yes i meant evaportaor! sorry very busy weekend, and the fridge breaking down hasnt helped.

1) The defrost stat open circuit
sure, but where is it? i cant see any stat, just two encapsulated NTCs.

2) The defrost elements open circuit
again, i cant see any obvious element, where should it be located?

3) The control pcb not initiating the defrost cycle.
Is this the board in the compressor compartment? or is there another?

Thanks for the tip with the power, i’ve been working on brown goods for a long time.

BOB.SMTH

[bob.smith]

Re: Zanussi ZX99/5SI – freezer not defrosting

*** UPDATE ***

Ok, its fixed!!

got zanussi to come a take a look see. the tech that looked at it was a bit confused as to what it was, but took a guess at it being the sensors, and plopped a new set in, despite thinking that they should not go in the first place. Its been fine since.

cheers,

bob.

[Author]

Posts