Vaillant F23 fault, Reading

[naylorpd]

I have a Vaillant Ecotec Plus 424 boiler in a closed heating system with 13 rads and 4 towel rails. Rads are steel, pipes are plastic kind of "modern microbore". System water pressure is 1.1 bar. It's a fairly new house, built in 2016. The boiler was last serviced in January 2019.

For the last few days I have been suffering an F23 fault. I bled all the rads tonight but there was no air in the system. I'm not sure how I can get blockage in a sealed system with inhibitor and plastic pipes.

I need to fix this ASAP because I live abroad and need to go home.

What's it likely to need?

If I'm reading heatable.co.uk right then it's either a new pump or a power flush - is that right?

Second question - as I live abroad, is there anything I can do to my existing boiler to be able to see any error codes via an app? The house is on BG Hive, but the Hive system says it is on even when the boiler is in fault status. The only way I'd know is if the temperature in the house fell below the minimum I'd set. I can get a neighbour to reset the boiler, but it's really happening too frequently and I need to fix it.

Thanks for any advice

 

[Deleted member 120897]

Could be the pump, ntc’s, a kinked plastic pipe, a valve closed somewhere et al.

 

[naylorpd]

Ho hum...none of the above, neither my sources or @ChrisB1982.

Bad installation....in a 2016 new-build installation they should have put a 5-core cable between the boiler and the thermostat, but they only put 4 cores. Having screwed this up, they then wired the boiler using 3 of those cores, which is how it would have been done in an old house where you couldn't put a new cable. So the boiler was still trying to pump out hot water when the thermostat was closing everything down and not letting water flow - thus the output was hot and the return was cold, hence the F23 fault. Or something like that....

 

[RoryD]

Open the bypass by 1/4 turn increments. Done this on an Ecotec Pro. Thiis should reduce the diff.

 

[John.g]

What is the make/model of pump?, does it display the power in watts W?.
Can you read d.40 flow temp & d.41 return temp, while its running normally.

Old thread!!

 

[Vee]

F23 being a circulation fault could point to pump, flow and return sensors, deposits in heat exchanger etc. Tackle the pump first. Check filters and bypass settings (if fitted, fit one if it hasn't got one, its external to the boiler) and that the pump overrun is wired in correctly.