We got a fantastic email toward the end of last week from one Dave Reeves, DipEE, MIET. Dave’s a customer of ours, coming to his son’s rescue when his fridge wasn’t cooling. I’ll leave you with his thorough, detailed and particularly helpful walk through on repairing the fridge.

Introduction

My son had a Hotpoint FF200E fridge/freezer which was about three years old. He was complaining that the freezer part was working but the fridge was no longer getting cold and stayed at normal room temperature. My daughter-in-law phoned a few freezer specialists who wanted around £100 just to come and look at it and, without knowing what the problem was, couldn’t guarantee a repair or the cost of parts if necessary. Dad to the rescue. A trawl on the internet revealed that this had happened to other people and various “solutions” were suggested, some more useful than others. Here is what I found in detail. It might save some people the cost of a £100 just for a defrost or the unnecessary purchase of a new fridge/freezer.

Fridge/Freezer Design

These fridge/freezers have just one cooling system located in the freezer compartment (the lower half of the unit) which normally runs at about –20 degrees Celsius. To chill the fridge in the upper half, which normally runs at about +3 degrees Celsius, cold air from the freezer compartment is sucked up through a duct, hidden at the back behind a panel, into the fridge compartment by a fan in the freezer compartment. There is a temperature sensor in the fridge connected to the electronic control circuit (a printed circuit board round the back) which operates a stepper motor hidden behind a panel in the top of the fridge which closes a flap at the upper end of the cold air duct and also stops the fan running when the fridge reaches the desired temperature.

The fridge/freezer is (in theory) “self defrosting” as follows: Frozen moisture from the air inside builds up principally on the cooling element in the freezer and so, at regular intervals, the cooling element is automatically heated for a short period to melt the frost. The melted frost then drips down into a shallow V shaped channel, runs out through a hole to the back, through a short soft plastic pipe with the end pinched together (presumably a crude non-return valve) and into a tray mounted on top of the motor. The heat from the motor evaporates the water in the tray back into the room.

Investigation

When I removed the two covers at the back of the freezer compartment I was quite amazed at what I found. The whole of the lower part was a solid block of ice about 400x150x50mm. This encapsulated the lower part of the cooling element, blocked the drain hole, the V channel and completely blocked the opening to the duct which feeds the fridge. Because the duct opening was blocked by ice no cold air could be drawn up to the fridge. This had obviously been building up over some time. I would guess that the drain hole for the condensate (about 3 mm diameter) had become blocked at some stage. Possibly by ice where the condensate had refrozen before having a chance to drain out since I subsequently found no evidence of ‘foreign bodies’ blocking the drain tube.

Once the hole is blocked, by whatever means, the result is inevitable – assuming the freezer is in service. Each time it runs through the defrost cycle a small amount of water is generated which drips onto the existing frozen condensate and re-freezes on top of it. Over time this gradually builds up into the huge block of ice that I found. None of this can be seen just by looking inside the freezer compartment – even with the trays removed. All appears to be normal. The only clue would be a very gradual increase in the fridge’s temperature as the cold air duct became progressively blocked by ice combined with longer periods of the fan running.

Solutions

The freezer needed a thorough de-frosting. With such a large lump of solid ice at about minus 20 degrees Celsius it will take several days to melt of its own accord. So run down all the food in the fridge & freezer in advance or get a neighbour to store it for you in theirs. Switch it off at the mains, remove the freezer trays and leave the doors open. Put some plastic sheeting and old towels underneath the front and back to catch the ice as it melts – based on the above experience you may end up with about 3 litres of water! Leave it and be patient. Water should gradually appear at the front and, sometime later, it should start to fill the plastic tray round the back just above the motor. This will indicate that the drain hole has thawed out. Empty the plastic tray as required using a cloth or sponge. Eventually the water running into the tray should stop – indicating that all the ice has melted. If no water at all comes into the tray it would suggest that the pipe is blocked (assuming that a build-up of ice is the problem). This could be cleared carefully using (say) an offcut of cable flex or a bent paper clip or something similar poked up from the back.

Depending on your practical capability a quicker alternative is to remove the plastic panel(s) at the rear of the freezer compartment and carefully melt the ice with a steam cleaner if you have one. These are sold for wallpaper stripping but are really good for defrosting a freezer. Do not be tempted to chip away at the ice with (say) a hammer and chisel as you could puncture the freezing element and this would mean a new unit anyway.

Prevention

It’s difficult to say how long it takes for this situation to develop. The blocking of the drainage hole might be a random event but a search on the internet reveals that other people have had similar problems. Switching it off prior to going on holiday each summer might be one answer. A simple precaution would be to buy a fridge & freezer thermometer. These are available for a little as £2 to £5.

Check out eSpares line of fridge thermometers.

Thanks Dave!

Tags: Fridge Freezer, Fridge Spare Parts