Bosch upright freezer running continuously

[pip268]

The model is GSU 3401 GB/53 FD8105
In the past the evaporator unit has iced up, resulting in the freezer running but the temperature rising.

I last defrosted the evaporator on 8th May.

Now it seems in this warmer weather that the compressor is running continuously, although the temp. is staying at -18, and I’m worried about the electricity bill.

I pushed the “super” button but it never got any colder than -18, although after I had defrosted the evaporator last time it went down to -26 on super.

Is it time to get the thing recharged with refrigerant? I don’t really want to pay the Bosch fees.
Cheers

[bosch-engineer]

Re: Bosch upright freezer running continuously

The evaporator has probably frozen over again. You will need to completely defrost the unit. 24hrs is not always enough as the insulation is very efficient. Its not the easiest to defrost. You need to make sure all the evaporator is completely frost/ice free before switching back on. Although it may look clear from the front, there is probably an ice blockage around the circulating fan at the rear of the evaporator. Best to leave it switched off for a few days the with door open. When you are happy its completely defrosted, check to make sure the door is striking the door switch correctly as this operates the fan. The fan should run as soon as you close the door although does not always run continuously. A re-gas isn’t always a good idea & is only a short term fix. If the original gas has escaped, then there must be a leak & can be difficult to cure.

[pip268]

Re: Bosch upright freezer running continuously

Thanks Bosch-engineer.
I will give it another defrost. Actually last time I took the evaoporator cover off and sprayed hot water in it for quite a long time.

The fan is running when I close the door at the moment.

One thing is bothering me though, it’s a few years old now and when it was new the compressor just used to run for a few minutes at time to maintain the temp. & didn’t need a defrost until it was about 3 years old & now the derost routine is only months between each one.

Should I cut my losses and get a new one?

[bosch-engineer]

Re: Bosch upright freezer running continuously

You say at some point in the past that you have squirted hot water into the evaporator! This may have caused the thermal fuse to go open circuit. If the thermal fuse is open circuit, the defrost heaters will not operate causing continuous problems with frost build up. You can identify the thermal fuse by looking for a black oval tube shaped device about 15mm long pushed into the fins of the evaporator with 2 black wires leading to the connection block. It should have continuity when tested with a multimeter.

[pip268]

Re: Bosch upright freezer running continuously

I’ve just peered into the evaoporator and it’s completely iced up. I’m goung to deforst it & then check the thermal fuse.
Actually I only sprayed water into it because that’s what the last Bosch engineer did!
Thanks for the advice Bosch engineer.

[pip268]

Re: Bosch upright freezer running continuously

I couldn’t see the thermal fuse pushed into the fins but I made a note of the plugs that are connected into the upper left section of the evaporator.

There are four plugs, first is white with 2 black wires and they are open circuit.
Second is gey plug with 2 white wires reading 285 ohms.
Third is Black with 2 white wires reading 2.5k ohms
Fourth is red with a grey & purple wire reding 49k ohms.

@helo_75, the bloke is trying to help me, constructive info would be welcome

[admin]

Re: Bosch upright freezer running continuously

non constructive repies deleted..

Please argue via PM if you wish and not in public forums

Bryan

[pip268]

Re: Bosch upright freezer running continuously

Well I shorted out the 2 black wires, assuming these were for the thermal fuse.
The ice that had built up from the last defrost has gone and I’m just keeping my eye on it for now.

[bosch-engineer]

Re: Bosch upright freezer running continuously

I dont think anyone has or would suggest shorting out any safety devices. I would not try this method at all, it could be very dangerous. If there is a fault on the PCB, the heaters could remain on causing a fire if you have shorted out the safety fuse. ❗ If in doubt, call in an expert. Your safety is paramount.

[trikidik]

Re: Bosch upright freezer running continuously

NEVER. Not advisable to short out the fuse.

[pip268]

Re: Bosch upright freezer running continuously

Oki doki.
Iv’e removed the short.
Any ideas where I can get a replacement thermal fuse?
Cheers

[iadom]

Re: Bosch upright freezer running continuously

Bosch Spares

[pip268]

Re: Bosch upright freezer running continuously

The thermal fuse is not listed in the exploded drawings & parts list online.

[trikidik]

Re: Bosch upright freezer running continuously

bosch part no 164234 (temperature limiter)

[pip268]

Re: Bosch upright freezer running continuously

Thanks very much trikdik.
As I can’t access where the present fuse is located, (it’s round the back) will it bo OK to stick it into the fins at the front?

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