Clicking sound from Whirlpool side-by-side fridge.

There appears to be a common defect with the Whirlpool American-style side-by-side fridge-freezer units sold in-and-around 2003 in both the European & US markets. The symptoms may range but are typically that the fridge will fail to cool and/or you will hear a frequent clicking from the rear of the unit or from the lower cooling vent. The replacement control unit costs around €240. But, the module is simple to repair and can be as cheap as €15.

My fridge was on the blink for about 2 years, clicking intermittently but cooling OK; before it finally gave up, clicking at a rate of about twice a second.

Fridge-Freezer Model : S20B RSB21-A/G
Features: Ice and cold water dispenser.

The control units in these fridges are common across multiple ranges. The unit is made by ITW Ispracontrols.

The control unit (CU):

The functionalty of the board is also documented by ‘dufferuk’ here.

There are four relays on the CU. Three black relays for the various services: ice and water dispensers etc; and a fourth orange unit for the compressor. The orange relay is the one which makes the distinctive ‘flapping’ sound.

Each of the relays is controlled by the Ispracontrols CPU through a traic (electronic switch). A capacitor and a bridge rectifier serve to power to the relay coils from the mains supply (being 24V DC relays).

The fault occurs as the axial-polypropylene capacitors degrade over time, typically having lost 50% of their capacitance at the point where the control unit fails, so the degradation causes the relays to 'flap' on and off.

There is also a secondary and larger capacitor in the circuit which works to limit the current through the circuit. This should be replaced or boosted in tandem with the replacement of the primary capacitors It was the actual cause of the issues on my board, but I took the opportunity to replace all of the affected units while I had the CU out.



I measured the capacitance of the capacitors with my trusty Beha multimeter.
Of the four 0.22uF capacitors, two had retained only 0.13uF, the rest were 0.21uF.
The large secondary 1.0uF capacitor was reading 0.47uF.

As I had some 0.22uF and 0.33uF capacitors at home already, I decided to just replace the two 0.22uF primary units which had failed and to boost the 1.0uF secondary one from 0.47uF to a more acceptable level of 0.80uF with a 0.33uF capacitor.

What to do:
Obtain the spare parts first. This will enable you to return the freezer to service quickly instead of causing the food to spoil.

The parts I recommend are as follows:
4x 0.22uF / 220nF, Polyprolylene capacitors.
Maplin part number : N44CN @ €3.85 each.
Radionics part number : 190-8551 @ ~ €1 each.
And either…
1x 1.0uF / 1000nF, Polyprolylene capacitor.
Maplin part number : RG26D @ €3.75 each.
Radionics part number : 190-8315 @ ~ €1.30 each.
Or…
1x 0.33uF / 330nF, Polyprolylene capacitor.
Maplin part number : RG25C @ €3.75 each.
Radionics part number : 190-7823 @ ~ €0.61 each.

Please note that the Maplin parts are slightly longer than the original parts, so they may need to be stood slightly on-end to fit.

It may be possible to get capacitors with a lower voltage rating than the above parts. You need to replace like for like, so 250VAC is a minimum. Lower voltage capacitors will be slightly smaller, so they will make better replacements.

If you decide to boost the existing secondary capacitor using a 0.33uF or 0.47uF unit, you can either fit this directly on top of the old unit or to the underside of the PCB, as shown below.