A customer has a side by side built-in unit Thermador KBUDT4855 not cooling and was beeping nonstop. Also, the symbols on the screen were flashing. This unit has a DC compressor and inverter starting relay, which converts AC power to DC. I conducted several tests and find two issues. Inverter relay was receiving the power but did not send DC voltage to the compressor. This was the reason why compressor won’t run.
So, let’s speak about beeping and flashing screen. This is the very common issue with Thermador side-by-side built-in units. Reason for that is the bad capacitor on the control board. Unfortunately, in similar cases, we have to replace the whole control board. There is a catch from Thermador, they no more produce or support same kind control boards. Usually, there are 2 solutions for this kind cases. First, we can send an old board for the rebuild. This method is time-consuming and takes 2-3 weeks on average. Another solution is to buy the replacement kit from Thermador, which is visually different and requires to redo of wiring.
So, after discussing options with a customer we stayed with second option and order replacement control board kit.
Easy things first. I removed the top cover and panel behind. I replaced the defective inverter relay board with the new part. After I disconnected all wiring from the old control board and remove it. New replacement kit is the combination of PCB board and power supply board and comes together in the big metal housing. To install this kit you need to remove some metal panels and mount them in a different way on the refrigerator chassis. After this, you will have enough space to mount this kit. At last, you need to reconnect all wiring.
Finally, I turned the power ON and start the unit. All components had been tested and look fine.
Another happy customer!
