I found it was the pressure senser return cable open circuit. When I 'cleaned' the temp sensor the first time I must have moved the cable and that's why it worked (not me cleaning the sensor). I have just replaced the cable and the bioler started up first time. Don't know how it went open...
I've just metered accross the green signal return cable of the water pressure switch and unbelievably I think it's open circuit. I'm getting 5v supply to sensor but nothing back on PCB from green signal cable. However, if I meter at sensor itself, green cable shows 2.5v.
Going to double check...
Hi,
I have been having an issue with my valiant boiler which is approx. 4 years old. Last week I got the F.73 fault (water pressure sensor) but the manometer read 1.5 bar and the EV seemed to be correct pressure. I read on these forums that sometimes cleaning the pressure sensor would...