Hotpoint Fridge Freezer Temperature too high

[Lee]

Hi,

I have a hotpoint mistral FF92 fridge freezer. The temperature in both the freezer and the fridge has been climbing and falling continuously between -22 to -11 and +4 to +20 degrees respectively over the past couple of days. Although today, the fridge is just sitting there at

+20.

I've cleared all the fluff that had collected on the condensor behind the kick plate and tried it with both compartments 1/2 full and 3/4 full. It's been stood in it's current position for over a year.

It's making all the usual noises except there's no cold air coming through the vent in the top right corner of the fridge.

I'm not much of an electrician but I'd like to have a go at fixing it myself if it will save me the £90 call out charge from hotpoint and teach me a little more 'Fridge Maintenance'.

Any help would be appreciated.

Cheers.

[BigWallop]

If the unit has frost free, then this sounds about the normal procedure. A frost free unit actually allows the temperature to rise so it can displace any icing on the parts it needs to clear. It doesn't thaw any of the goods stored in the compartments, or shouldn't, because the de-frosting times are far to short.

When the temperature starts to rise way above zero in the freezer section, then you can start to worry.

[Lee]

Since we have a Mistral also, I kept a note of some previous posts :) Ours is a 8596 with the LCD display, but I think they are all similar.

Check the evaporator thermistor; (on the 8596, remove the fan cover in the freezer compartment and then the back panel and the thermistor is cable tied to the evaporator coil). It should read:

@room temp approx 3Kohms @0 deg C approx 9K ohms @-20 deg C approx 26K ohms.

There are two other thermistors, but this one is apparently the one that usually fails.

Lee

[N. Thornton]

Frost free or not? I assume you mean C. Any condensation on the outside, or dripping underneath?

Regards, NT

[Lee]

Thanks for that Lee.

I've taken off the fan cover. The fan isn't turning and the two pipes at the top left are frozen over. Also items at the top of the of the freezer aren't frozen whereas those at the bottom are (guess this is down to the fan).

Think I've identified the thermistor but how do I read it? Do I need some sort device to measure resistance?

Lee

[Lee]

Yep, you will need to check its resistance, probably easiest at the plug in connector, can you borrow a Multimeter or DMM - or someone who has one? ;) Might be an excuse to buy one of those £3 cheapies that Maplin and the like sell, they are good enough for this sort of application and will be useful for other things...

Obvious I know, but measure it with the power off!! :)

The usual failure mode of thermistors is open, so it should be fairly obvious if it has completely failed. Worth checking that the resistance is about right at the various temps though. If you can. This one is the one that commonly fails, apparently because of the constant freeze/thaw it has to endure, but there are another two additional thermistors that it could also be.

Also worth checking that the *fridge* door switch works correctly, because this stops the *freezer* fan, when the *fridge* door is open - at least it does on ours...

If the thermistors check out ok, then it's probably engineer time, if the unit is worth it.

Lee