F4 fault code on a Honeywell Smart Fit heating system

[@vibgaming]

thanks for this video. i have the F4 fault as described. if i reset the system it will go away for a week or so then it will come back. i read the fault can be caused by not only the valve but also the electronic units, so i went and bought a 2nd hand kit/ system and replaced the electronics but the problem persists. now i guess i'd have to change the valve which i have a brand new spare for that came with the kit. do i risk flooding at any stage if i remove the valve as per your video? must the lever be centered before i remove the existing valve? thanks in advance.

[@mysterizedoutcast]

did you replace the valve or find a solution? I have the same problem but have not replaced any parts yet. With the F04 error present the valve still moves up and down by itself periodically without the rest of the system working, so it doesn't appear the valve is stuck. If I turn the power off and on then the system works fine. The F04 error keeps appearing about once a day now. Perhaps the base unit or control unit is at fault.

[@vibgaming]

@@mysterizedoutcast i replaced both the timer controller and the receiver box and the problem went away iirc. I never changed any valves. I have since changed to a combi boiler and ripped out the water tank.