Yet another Hotpoint Mistral Plus (frost free) temp problem

[MKR]

-21 is good, shows everything is good refrigeration wise…. you just need to get the fan to work.

Has the door dropped where it hits the fridge light switch?

Does the fan work (for a short time) when you power-up with the fridge door open?

[chestnuts99]

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

Hi, yes! the little internal fan in the back of the freezer compartment runs for about 2-3 secs when powered on …what does this mean?? thanks for your help 🙂

[MKR]

It shows the fan is OK…. I think you have done everything you can, you have changed the yellow thermistor, checked the light switch, cleaned out the condenser and checked the condenser fan-motor.

The fan will operate when the yellow thermistor senses the evaporator assembly is cold enough… a form of fan delay after defrost. So when the fan fails to operate, it is usually due to the sensor/PCB falsely sensing, or the evaporator not getting cold enough (compressor or condenser fan faulty).

[chestnuts99]

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

Hello again, I thought it must be the PCB after all, so I got it out and saw a burnt looking part at the end of the board where the LCD display is situated just behind the buttons that control the temp and compartment being viewed etc.
Ho Ho thinks I , I’ve finally got it! The heat appeared to have affected a triac(BT139-600) and a couple of 330 ohm resistors so I replaced those (quite cheap under a tenner) put it all back together and hey presto…….. nothing, nix sweet fanny adams!!! The problem is still the same as when I started, I guess I didn’t find the real problem on the board. I am very close to giving up now as I can’t see me spending another £120 on a new board and still having useless lump of metal and plastic in my kitchen. Any advice gratefully received before I finally kick this thing into touch….Regards Dirk

[rickard]

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

With the freezer at -21 open the fridge door for 20 seconds then shut it if the evaporator fan in freezer runs for a few seconds then stops you will need to replace the fan motor, dont be confused because if you take the fan out and run it on a bench it will work fine

[chestnuts99]

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

Thanks so much…..I am doing it now. Can you tell me the reason why this is as you describe….please don’t think I am doubting you at all….I ‘m just interested to learn:-)
Cheers Dirk

[chestnuts99]

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

Thanks Rickard…it did kick round for a sec. What a weird problem!
Is it something to do with the resistance of the fan and the sensitivity of the circuit board which is not reflected on the workbench and straight mains environment? I guess I’ll look for a fan now.
I’ll post the results….this has to end soon!
Regards
Dirk

[chestnuts99]

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

It worked! The little fan is whizzing round! So now I will put all the plastic baffles and cladding back on to direct the cold air to the fridge and see if it gets cold at last!
Regards
Dirk

[chestnuts99]

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

Done, fixed, mended, finished..at last. Thanks to everyone that helped!
Regards

Dirk

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