FFA90 thermistor problem (FFM90 / FFS90)

[Mel_P]

I have seen lots of threads on this topic, but not for this model, and supsect that one of the thermistors has drifted.

The problem is no cooling - whole fridge-freezer shuts down. All parts seem operational (control board, freezer fan, compressor, damper in fridge compartment).

Searching the internet it seems the first solution is to swithch it off for 24 hours and try again. I check all connections to control board etc and this made no difference so I left it turned off overnight and plugged it in - hey ho it worked. OK for 4 days then exactly the same problem (lucky I have the old fridge and freezer in the garage!). Switched off again and will try tomorrow. If it works it suggests its the thermistor(s) slightly out of range confusing the control board.

Does anybody agree? Which thermistor - the one at the botttom of the freezer compartment, or the one in the middle please?

If so, I have searched the web but have not found an on-line supplier - can anyone help here.

This has got to be cheaper than paying a Hotpoint engineer £90 to tell me the same thing?

So - do you agree with diagnosis?
- where can I buy suitable thermistors (part numbers???)?

Here's hoping somebody can help here. Many thanks for any guidance. Thanks, Mel P

[tonto33]

I think the problem may be a blockage in the air duct from freezer to fridge either that a faulty baffle or again the evaporator fan is jammed and not circulating cool air up to fridge as it not cooling this model doesnt have thermistor

[Mel_P]

Hello tonto33. The baffle is working - I have taken the top cover off in the fridge compartment and the baffle opens / closes and the duct is not blocked. The fan is also free and operates when required.

I initially took the back panel off the freezer compartment and there appear to be 2 thermistors - one at the bottom left and one near the top - I can't remember the colours - red / blue (as I have already fixed the panel back on)? They are about 2cm long x .5cm diameter - with a white cable going to the junction box.

These are wired into the junction box near the thermal fuse. I assumed that these are thermistors. If not -what are they please?

?????????

[Mel_P]

Here are the sensors:

(tried posting image link but not yet allowed)

There is a white one top left above the cooler

There is a white one with a red mark on the lead about an inch from the sensor head bottom left

Sensors have rounded end.

UPDATE - left off overnight - woudn't come on - took off back panel - warmed up bottom sensor with fingers - Compressor BURST into life no cooling !!! Lets see how long it runs for?


??

[Chunk]

Hi heres the link to the service/installation manual if you have`nt got it.

http://imagebank.indesitcompany.co.u...ce/HBFFA90.pdf

Its pdf so have to download it.

I have this fridge/freezer myself so i`ll have a look at it in a bit and see if i can see anything.

[Mel_P]

Thanks CM - I still have paper issue - but it stops where I want to start - all is OK when it's working - but the unit has stopped (switched itself off andcompletely warmed up) twice in a week and restarting it seems to require the bottom sensor ro be warmed up.

I think I need the "service" manual - it appears on some web site for £23 + post - I may have to splash out - unless you know a link to this?

Mel P

[Chunk]

Hi Mel_p

I cannot find any manuals other than the one i posted above.

I had a quick play with my fridge(ffa97)its roughly the same and fiddled with the sensors,each time it flashed a fault on the display panel.Are you getting any error readings when the fridge has stopped?

Hotpoint are not really helpfull when it comes to revealing spare part codes other than ice trays.

The only other thing to suggest is phoning hotpoint or currys technical and asking them what type of sensors they use and if they can source one for you.

Other than that,there are a few really good guys on this forum who are`nt online at the moment who could help,but it just means waiting for them to respond.

[Mel_P]

No error codes - just stops and warms up. Then I have got it going by "overwarming" the bottom (red) sensor - I presume a thermistor.

I have requested spares from "partmaster" and am awaiting their response - they requested serial number which I have supplied.

Thanks, Mel

[Mel_P]

Uploaded pics?
(just found you can attach)!

[kiwireeferman]

I Imagine one sensor would be for defrost termination and the other would be freezer temperature.

I thought thermistors were pretty standard, if you get an accurate ambient temperature and then measure resistance you can work out what it is. The NTC type seem to be more common than PTC.
I have made up my own with soldered tails and then heat shrinked the hole assembly.

The red mark on one would be to ensure the assembly line worker fitted it into the correct position.

[Mel_P]

Hello kiwireeferman (NZ is a great place!)

I have been informed that thermistor leads are set in the foam and not replaceable!

It's runnung at the moment but not confident it won't shut down again - intermittent faults are the worst.

Mel

[tonto33]

got them senors wont u do is u cut the wires and use connectors to fit new ones then they work.. pm me if u want some

[Mel_P]

Hi Tonto33, having tightened / wobbled / took apart all connections I could find, it is still working after 3 days - so perhaps it was a connection that had developed a higher resistance - and is now OK.

But I still don't trust it - BUT I will wait a while before I start chopping thermistor leads!! Are they similar in price to other (e.g. "Mistral) thermistors - might get them as emergency spares - give it a week!!

Thanks Mel

[tonto33]

they cost slightly more check out my website www.reconwarehouse.com they on there

[Mel_P]

Thanks - freezer still going but i have your link!
Mel

[Mel_P]

Quote - "Thanks - freezer still going but i have your link!

Mel

Well it lasted till now and suddenly overnight it switched off - having breakfast - whats that annoying beeping - YIKES freezer not cold - dump everything into emergency (old) fridge and freezer in garage.

Defrosted everything - ran 3 days then stopped overnight again. Don't beleive its the thermistors.

Could be PCB - are these still available?
Could it be the defrost heater - but don't see that this would produce the same symptons?

Suggestions please? Mel

[TECH TIM]

sounds possible that its not iniating a defrost cycle and there fore shuts down i dont know these brands though ill look at posted manual and see if i can see nethin

[Mel_P]

Thanks - it could do that if defrost heater is open circuit?

[TECH TIM]

possibly, it may give a few attempt to defrost, if say on the fith or sixth attempt it didnt defrost, it may shut whole system down, usually if it beeps its giving a fault code, in my experience any way, when beeps see if any lights are on in a certain pattern, or if beeps 5x and pause or 8x and pause, that may be a fault code, in my exp if a defrost heater failed and sensor didnt sense temp increase in 5-10 mins it would fault out, ie you wouldnt get 24 hours out of if that were the case, but like i said never seen a fridge like this one before, manual was no help unfort, we dont have hotpoint in aus but ive seen alot of fridges in my time

[TECH TIM]

try running it for a few days and take cover off evap everyday to moniter evap condition see if any ice builds any where???

[Mel_P]

It's been running 3 days now! I will just leave it going till it stops then look for ice!

Thanks.

[TECH TIM]

check it before it stops id check now see cond of evap coil, if alot of frosty ice iindicate missing defrost for some reson could also be faulty pcb

[344martin]

Defrost cycle will be dependant on compressor running time. I.E. if de-frost cycle set to come on after 24hrs running, it may take 3 days to accumulate 24hrs actual run-time

[TECH TIM]

Most fridges defrost anywhere from 6 to 12 hours run time

[Mel_P]

Well its now been going 2 weeks - daren't strip it down to look if any ice forming or if defrosting properly!