Vaillant ecoTEC Pro 28 faulty printed circuit board

This was a much needed repair of a second generation Vaillant ecoTEC Pro 28 Combination boiler, in Hillsborough, Sheffield, S6.

The boiler in this case would attempt to fire up and then go to a blank screen for a period. With these boilers and the older glowworms, if the screen is blank then you typically disconnect all the connections from the board and se if the display lights up.

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If the screen lights up then this usually indicates that there is a component which has failed and is causing the problem.

With this boiler, the circuit board would put power onto the fan which would spin for a second and then the screen would go blank for a period.

This would usually indicate an issue with the fan. If you speak to Vaillant technical support they would suggest to disconnect the fan and see if the appliance goes to the F.32 fault code.

If it goes to F.32 then the fan fan is faulty and not the printed circuit board. However in this case upon connecting a fan to test it, the appliance did a similar thing and then displayed the F.27 fault code! I found out afterwards that the customer had seen the F.27 peridiocally since it was installed and thought this was normal. This fault code is usually indicative of a faulty printed circuit board.

Looking for a Vaillant ecotec printed circuit board(pcb)?

I have created a separate page with links for anyone looking to purchase a Vaillant printed circuit board.

So this boiler needed a new pcb which fixed the problem. Usually these Vaillant ecoTEC boilers are quite straight forward to fix but sometimes you do get weird faults that don’t make any sense.

This is the challenge with boiler repairs sometimes as most of these parts are expensive and most of them cannot be returned once fitted – especially printed circuit boards. The printed circuit board for this particular model retails at around £230 +.