F20 Error Code Vaillant Ecotec 630 R1 Boiler

[tpaling]

Hi,

I have the above boiler and last night i had loss of pressure due to a small leak from the pump unit. obviously, the boiler cut out due to lack of water pressure. The boiler has been making humming noise for a while now and i suspect that this is the pump. I mended the leak and left the boiler on all night for heating and hot water. This morning the boiler was still running so i turned it off and went to work.

However, i came home today and the boiler was not working and water pressure in the boiler had dropped slightly. I attempted to start the boiler but every time it fired up it lasted for approx. 10 seconds, the water pressure went up and the boiler cut out. The error code F20 was then displayed, which according to the installers manual is due to, 'Flow-NTC not correctly thermal-connected or defective; appliance does not shut down'.

I am not sure whether it is the pump or another problem and any advice would be appreciated.

tpaling

 

[Agile]

A DIYer should not really be opening the front cover of this model because it forms the combustion chamber outer cover.

Based on the description of the fault code what investigation have you done to point you towards the pump?

Tony

 

[Bunnyman]

Where was the leak on the pump unit u managed to mend!

 

[tpaling]

Thanks for your response, removed pump today and tested with a multi-metre which indicated that there was not a full circuit. Replaced pump and all washers and gaskets relating to diverter value, expansion tank (which I re-pressurised) and the pump header and housing. Boiler fired up first time and we are now as warm as toast. Happy days! Thanks