How the Bosch kgu34665gb/01 Fridge Freezer works and common faults and parts

September 28, 2016

Paul Says:

Bosch kgu34665gb/01 Silver Fridge Freezer

Bosch Fridge Freezer Spare Parts

This article will show you how a Bosch kgu34665gb/01 Fridge Freezer. We will be looking at the cycle of the fridge over a few days with our graphing system where the data is supplied by our unique fridge test equipment which will be available later in the year.
I will be explaining how to your Bosch kgu34665gb/01 Fridge Freezer cycle Works and how the areas within the fridge stay cold, we will also look at the common faults and how to rectify them.

Common faults

The fridge compartment maybe getting warm,
on a single compressor frost-free fridge freezers this may be an air flow problem coming from the freezer due to heavy ice build-up on The Matrix this may be due to the freezer not defrosting correctly this can be a faulty element or ntc sensor a faulty circuit board one of the heater cut outs are not working correctly and therefore not letting the defrost take place,

Things to check do a test
Heating element
NTC sensors
Fan motor
Safety cut outs for heater
Clear air flow passages

If all your food in the fridge is getting too cold and the drinks are freezing then this may be a thermostatic problem.
If the fridge is not getting cold you need to check if the compressor is running,
If the compressor is not running then it is normally one of 3 faults.
1. thermostatic failure ntc sensor or pcb
2. Starter relay failure
3. The motor has gone open circuit.
If the motor is running then you may have a gas leak problem.
There is not enough gas in the system for the refrigeration cycle to take place, or the compressor is not pumping the gas around the refrigeration circuit this can be due to a weak compressor, or a blockage in the system (sometimes the dryers block)

Notes on compressors

Compressor Running:
The compressor is a motor which pumps gas around the circuit, you can tell when a compressor is running because they get warm and you can hear it running if you listen closely. They have a starter relay on them which shuts the compressor into life, they also have an overload relay this is designed to protect the motor, Both of these can sometimes go faulty and need to be tested you can see our other videos on these.

Compressor Not Running:

The compressor may be cold and you will not be able to hear a noise apart from.
When a compressor is not running you may here a clicking noise every few minutes this may be the overload sensor cutting out due to a faulty starter relay or compressor.
A useful technique is using a screwdriver, placing the pointy end on to the motor of the compressor and the handle to your ear you may hear a humming noise this will be the windings as the motor is trying to start.

You can test compressors

It's a good idea to verify that the compressor is OK: Use a multi-meter (make sure fridge is unplugged!) and check resistance across each pair of pins on the compressor itself (3 combinations total). Two of your readings should be smaller than the third (the two have the same resistance on my fridge), and the third should be total of the two (see diagram, R-S goes through C). For example: S to C 7 ohm, R to C ohm, R to S 14 ohm. If it is significantly off from this sum-total rule, you're probably have to get a new compressor as the windings are not good. You should also check that the windings are not shorted to chassis (either of the three pins should not go to chassis which is the earth)

Other things to check
Door seal/s faulty or not sealing allowing moist air into fridge or freezer may be causing excess ice build up
Gas Faults
Basically this is pretty much an engineer’s area, but the causes are as follows in the main:
Shortage of gas on appliances under a year old or have just been moved
Blockage or choke in pipework
Changeover valve faulty
Compressor pumping weak (highly likely on older machines 8 years or older)

Bosch kgu34665gb/01 Fridge Freezer