Yet another Hotpoint Mistral Plus (frost free) temp problem

[chestnuts99]

It seems there is a long list of folks having problems with these Hotpoint machines……..
During the recent hot weather, ours started to lose freezer temp but seemed to recover if we kept the kitchen door open…. today the fridge is +25 and the freezer -9. I read this forum for advice and found the whole condenser and fan choked with dust/fluff.I hoovered and brushed out thoroughly and checked the little in-line fuse…all ok. So I turned it back on about 8 hours ago and it is now +25 and the freezer -10 with alarm flashing, it did get up to -15 at one point.
I looked for the thermistors but couldn’t find find them. Where are they and what do they look like? Does that sound like the problem? The fan that blows into the condenser is working ok. The black doomed component not sure what that is (compressor?) is very hot to the touch. I guess the electronics are in the front panel at the top but I can’t see how to open this up.
Does this sound like a possible DIY fix, I can do soldering etc. no problem. Any help or advice appreciated….Thanks Dirk

[Dales-Electronic]

Re: Yet another Hotpoint Mistral Plus (frost free) temp prob

There are a number of different versions of the Mistral, please supply the model number and serial number and we’ll see what we can do 😀

[chestnuts99]

Re: Yet another Hotpoint Mistral Plus (frost free) temp prob

Many thanks for your reply…the dataplate (sticker) inside gives Model:F880Z;Serial no:48113186
Hope that clarifies……… Dirk

[chestnuts99]

Sorry I think that should be FF80Z

[chestnuts99]

chestnuts99 wrote:Sorry I think that should be FF80Z

Did anyone have any thoughts about this…we are getting a bit desperate!

[Dales-Electronic]

Re: Yet another Hotpoint Mistral Plus (frost free) temp prob

Firstly take out the drawers in the freezer, remove the back panel inside and at back of freezer compartment. See if the evaporator (heat exchanger) is blocked with ice, if so defrost it off checking that the supply and return pipes leading up the back into the fridge are clear of ice. Once and if this is clear check that the internal fan is running, it will not start until the temp in freezer is -6C so you may have to wait awhile. At the back check that when the motor (compressor) is running the adjacent fan is also going. If all of these are OK you are either short of gas or you have a compressor fault and will need a service engineer. The thermistors are colour coded green, yellow and white and are in the freezer cavity behind the back cover. Good luck and power off when you take it apart please.

[chestnuts99]

Re: Yet another Hotpoint Mistral Plus (frost free) temp prob

Hi Thanks for the reply. I hadn’t noticed the deeply recessed screws in the bottom of the freezer.

so….the current state after leaving the machine to defrost for about a week, is that after 4 hours on fast freeze the freezer reached -19c but the fridge refuses to move below room temp…. the heat exchanger and pipes associated with it are all clean and ice free. I found the internal vents in the freezer and 2 in the fridge, one behind the light panel (sneaky!) they all seem clear………. I guess I’ll have to wait to see if the little internal fan works when the freezer hits -6 again. Is this the fan that will get the fridge to the correct temperature? It rotates freely enough…does it have a fuse somewhere….?

Thanks again

[chestnuts99]

Re: Yet another Hotpoint Mistral Plus (frost free) temp prob

Well the freezer is now down to -13 and the little internal fan is not going round….I guess I’ll power off and test it …..Can you still get these if a new one is required? Cheers……..

[chestnuts99]

Re: Yet another Hotpoint Mistral Plus (frost free) temp prob

Hmmm the fan works fine on the bench although it did seem to get very hot after about 30 secs of running (2×15 sec bursts). I guess this means the power is not arriving at the terminal block on the rear wall…… is this likely an electronic control panel failure, or a sensor failure ? Cheers……….

[chrisj87]

sounds like the thermistors to me iv changed 100s of these we change the green and yellow together there at the back of the freezer behind the rear cover 😀

[Dales-Electronic]

Re: Yet another Hotpoint Mistral Plus (frost free) temp prob

Before you go down the route of changing the thermistors, do this – remove the top baffle that is in the fridge compartment and leave it with the cables connected and hanging. Then see if the temperature in the fridge goes down. If it doesnt then change the thermistors green/yellow as this is the cheapest option, if this doesnt work you have a pcb fault.

[chestnuts99]

Re: Yet another Hotpoint Mistral Plus (frost free) temp prob

Thanks guys, I tried removing the flap in the fridge to no effect…..and I already ordered the yellow thermistor. Should I wait and order the green one too or can I try it and see if just the yellow one is the fix? Can I damage anything by doing that or is it just a case of it won’t work until both are changed? Cheers

[MKR]

Now I know you have said you have cleaned out the fan and condenser…. but any Mistral F/F where the temp of the freezer section is only -6, I would be looking to see if the condenser fan is turning correctly.

[chestnuts99]

Re: Yet another Hotpoint Mistral Plus (frost free) temp prob

Oh dear, I have been waiting for the new thermistors to arrive which they did today. I replaced both and wait for it…..~@!!# nothing..freezer is -21 fridge is room temp and the jolly fan inside resolutely refuses to move.
Is it time to give up…how much is a pcb? Cheers

[chestnuts99]

just to be clear, I replaced the green and yellow thermistors………

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