Hotpoint Mistral Plus (model 8596P) Fridge Freezer Temp Prob

[Shiner]

Can anyone please help??? Fridge Freezer (Hotpoint Model 8596P/Frost Free) Mistral Plus is about 7 years old. Have recently noticed increase in temperature in the fridge and the temperature warning light flashes continuously. Have checked the airvent grille at bottom and removed an extraordinary amount of accumulated dust with the hoover. Have checked the door seals on the fridge and freezer, all seem okay. Fridge temperature is between +13 (on a good day) to currently +15; the freezer is constantly on fast freeze but only shows -5 (book reckons should be between -18 to -24).
Have switched off the unit for 2-3 hours, emptied the freezer (all contents still out) and switched back on. Unit has now been back on for 10-11 hours showing -5 (freezer) and +15 (fridge). I can hear ‘something’ quiet and recirculating noises from within the unit, so assume it is still working.
However, when removing the airvent grille I have noticed the following – (a) to the left hand side (directly underneath the freezer) the unit is quite hot to the touch (think this is where the compressor/motor is located) and (b) now and again the ‘fins/pipes’ on the right hand side become hot.
I noticed (when the freezer was full) that the bottom tray contents had defrosted whereas the 3 compartments above that remained frozen.
There was no sign of frost build up or whatever when I emptied the freezer.
The only other point I could make is that I gently moved the unit the other day when I pulled it away from the wall, but did not tip it up or anything. Dont know if that is relevant.
Any advice would be greatly appreciated…….thanks.

[Simon46]

Re: Hotpoint Mistral Plus (model 8596P) Fridge Freezer Temp

Can the fan be heard running in the freezer. Opening and closing the fridge door will change the state of the fan operation (fridge light on or off)?

[Shiner]

Re: Hotpoint Mistral Plus (model 8596P) Fridge Freezer Temp

Hi Simon46. Sorry for delay but the f/freezer is actually at my girlfriends house and had to go round to check.
Okay, the fan cannot be heard running when I open/shut the fridge door (repeatedly).
The fridge light operates with no problem, i.e. on when door open and goes off if I simulate shutting the door.
Any ideas please?????

Thanks, Shiner.

[Dave_Conway]

Re: Hotpoint Mistral Plus (model 8596P) Fridge Freezer Temp

Shiner wrote:There was no sign of frost build up or whatever when I emptied the freezer.

To check this properly you need to remove the rear panel of the freezer compartment, plug removed from the socket :zap:

It sounds like one or both of the freezer thermistors may have failed, the usual cause of problems with these models, apart from the switch on the fridge door not operating, normally casued by the heavy 4 pint milk containers which is what Simon was getting to I think.

Dave.

[Dales-Electronic]

Re: Hotpoint Mistral Plus (model 8596P) Fridge Freezer Temp

Just to add to the aforemention – With the fridge/freezer unplugged, remove the back cover and vacuum out the black grill in the base. Having done that (leaving cover off) reconnect appliance. Check that base fan is running. Now, when the motor (compressor) starts to run, check the pipe going into the black base grill area (after about 5 mins) and see if it is warming up – warning – it may get hot, so be careful. If it is hot, leave the ff running and see if the temperature comes down in the freezer. From memory the internal fan will not switch on unless the freezer temperature is in excess of -6C. If the temp is going toward the set temp (without the fast freeze being on) you may have cured the problem – however if you still have a failure to get down to temp you may have a shortage of refrigerant or a duff compressor. If you can get the freezer down to the correct temp but the fridge is way out, you suspect the thermistors, if the cooling is suspect then perhaps the refrigerant/compressor. Good luck and if you need further help theres always good advice on the forum.

[Shiner]

Re: Hotpoint Mistral Plus (model 8596P) Fridge Freezer Temp

Thanks to both of you Dave & Dales-Electronics! For Dave – I will take the rear panel off (to check for frost build up?? around the thermistors??) and will also check as per Dales suggestion to build up of dust etc bottom of black grill at the rear of the base. Incidentally, when I removed the front vent which exposed the front of the black grill (to the right) to say that there was an accumulation of dust was under-exaggerating. It was covered in THICK balls of dust, I got as much out as possible. Then all of a sudden the black ‘pipe’ grills becoming very hot for quite a while – I take it that was a good sign then????? I wonder if there is a huge build up of dust at the rear? Which may need vaccuming out?
When I remove the rear panel how will I know what the thermistors look like, or are they self evident? Also, are they expensive to replace and/or a DIY job?
By the way guys, the freezer is constantly running on fast freeze. How would I cancel this (as Dales suggests that I check it without fast freeze on)?
One final note, with regard to the fridge door switch. WHen I open and close the door I can clearly see the fridge light switching on and off, although I must admit that the alignment of the fridge door seems to have slightly dropped down on the left hand side and just about still makes contact with the ‘switch’ on the top which operates the fridge light mechanism. Like you say, she does load it up with the huge 4 litre containers.
Thanks again for all of your help.

[admin]

Re: Hotpoint Mistral Plus (model 8596P) Fridge Freezer Temp

Thanks Dave and Dales-Electronics for your advice. I thought I had solved the problem earlier.

Isolated power, took back off f/freezer (at base) – lot of accumulated thick balls of dust (hoovered out) and in between the black grill ‘fins’. So both front and back of the black grill now thoroughly vacummed.

Lightly tapped on the compressor with handle of the phillips screwdriver. Within 5 minutes the black grill was getting quite hot to the touch; the compressor was very hot (and humming sound from within) – but the base fan is still not working.

I watched the temperature on the freezer drop from -5 to -13 within 15 minutes or so. The fridge temperature dropped from +15 to +6 in same time frame. Then I went to watch Cheltenham Town FC get beaten by Swansea 2-1! Got back and noticed that the temps were now -9 and +12 respectively, the black grill was now barely warm.

By the way, when I took the back base cover off of the freezer I noticed that the ‘spindle’ or ‘metal pin’ that adjoins the fan to the fan motor seems extended. Are they supposed to be sticking out about 2cm??

So, like I said I thought I had cracked it but maybe not. Is the black grill meant to be hot constantly or not? Also, just to mention it but when the freezer dropped to -12 or thereabouts the temperature warning icon stopped flashing. But it is back on again now!

Any other ideas guys?? Thanks.

[Dave_Conway]

Re: Hotpoint Mistral Plus (model 8596P) Fridge Freezer Temp

I think we’re talking about two different fan motors here.

Are you refering to the one next to the compressor ?

If so, it should be running all the time (apart from during the defrost cycle).

Dave.

[Shiner]

Re: Hotpoint Mistral Plus (model 8596P) Fridge Freezer Temp

Hi Dave,
The fan that I was referring to is the base fan (which Dales-Electronics asked that I check is running). This is located at the back of the f/freezer (at the base) having removed the small rear base panel. The compressor is located to the right and a large-ish fan located to the left which I presume cools or distributes warm air from that area out through the front of the vent grill???
This was not working. I noticed that the spindle that the fan is attached to is prob about 2cm in length, poking out from the fan motor housing and was wondering if it has detached and should be more flush with the motor housing??
I have already checked the smaller fan inside the freezer compartment by removing the interior back panel.
When you say that the fan (next to compressor) should be running all the time (except during the defrost cycle) is it probable that it would NOT be running if the temperature warning light is on more or less constantly??
Thanks again.

[Dave_Conway]

Re: Hotpoint Mistral Plus (model 8596P) Fridge Freezer Temp

The red light coming on is caused by the fact that the motor isn’t running I would imagine.

Dave.

[Dales-Electronic]

Re: Hotpoint Mistral Plus (model 8596P) Fridge Freezer Temp

OK lets clarify abit – firstly assuming that you have removed the dust etc from the black heat exchanger in the bottom (condenser) the base fan should run all the time. If it is not running the appliance can not get rid of the heat and thereby will not get down to temp within the ff. So if fan is duff change it. Having changed it, run up the unit, check the heat exchanger is hot and watch the internal temperature go down (with the doors shut) If you cant get it below -6C the internal fan will not come on and to be honest you should look for a fridge engineer to bail you out. If you require someone, make sure they are familiar with this model. A link on the home page will get you a member of this forum if covered. Best of luck – Ian.

[Shiner]

Re: Hotpoint Mistral Plus (model 8596P) Fridge Freezer Temp

Thanks to Dave and Dales-Electronics for the advice.

When I cleaned the dust from the black condenser there was an immediate effect in that it became hot, the compressor became very hot and humming, the temperatures on both fridge and freezer dropped to +6 and -15 within minutes and the internal fan kicked in (like you said it would at -6)- so I thought brilliant!! Within 1 – 2 hours though it had started to creep up again. But like you say, if the base fan is not operating then it isnt getting rid of the build up of heat underneath the freezer??

Any idea what part number for the base fan, cost and is it possible DIY fix please?

Thanks again.

Shiner

[Dave_Conway]

Re: Hotpoint Mistral Plus (model 8596P) Fridge Freezer Temp

Typical, two versions of the fan motor 🙄

Serial number please Shiner.

Dave.

[admin]

Re: Hotpoint Mistral Plus (model 8596P) Fridge Freezer Temp

sounds to me like the compressor is weak, fridge temps should be around 5oC and freezer can be -25oC ish, if the compressor is running continusly and the temp is still bad in the fridge then it is either a partial block in the gas system, a weak compressor or low on gas.

i would sugest at this age it is weak compressor or partial blockage in the system.

call a refrigeration engineer which may be costly or buy a new one

rob

[Dales-Electronic]

Re: Hotpoint Mistral Plus (model 8596P) Fridge Freezer Temp

Hi again – Rob has a valid point here but until you get the condenser fan working (note the condenser fan should be running when the compressor is going) and without a fridge engineer at your shoulder I would suggest that you try this – take off the front lower grill and borrow or steal a fan heater. Put the blower on full (no heat) and point it into the condenser then check the temperatures. If they go down and stay down (the default settings on this are fridge + 2C, freezer preset at -20C) then your fault is the condenser fan, if however they go down and then start to rise and compressor is running all the time you are either short of gas or the compressor is duff. With either of the later you need a fridge qualified engineer.

[Author]

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