Hi guys,
So yesterday morning I woke up to a f75 error code on my 2006 vaillant boiler ecotec pro 28. After some research I decided to replace the water pressure sensor as the cheapest place to start. So in doing so, I isolated and drained the boiler, fitting new sensors, repressurised the expansion vessel to 1 bar and filled the system to 1.3bar and put the boiler into P0 purge mode. F75 code gone but still no hot water or heating.
Right now to give some background, last year I replaced the diverter valve on this boiler due to a leak and went through a similar process of above. What I weirdly noticed was after the 20 mins of purge mode the boiler did this weird loop thing for a couple of hours of just running on and off with the green light on the boiler flashing until finally it settled, and started working as normal and gave me my heating and hot water.
A few months later as discussed in my other thread regarding 1 radiator not working. I drained the entire system and refilled and again purged the boiler which takes about 20 mins and then again the boiler went into some weird loop of turning on and off with the green light flashing for an hour and a half or so until it settled and started working as normal giving me my hot water and heating.
However now to the present day, after replacing the water pressure sensor and purging the boiler, it’s been in this infinite weird loop of turning on and off with green light flashing and it hasn’t gone back to normal. Yesterday I left in on for 6 hours in this way hoping it would settle, it did not, switched the boiler off and purged again thinking still air in the boiler, same thing after the 20 mins just in and infinite flashing loop. Today same thing. Checked the expansion vessel pressure, boiler pressure, bled the system but still no luck, still in infinite loop and no hot water or heating. I have taken a video of what’s happening so have a look at this link:
Cheers guys
So yesterday morning I woke up to a f75 error code on my 2006 vaillant boiler ecotec pro 28. After some research I decided to replace the water pressure sensor as the cheapest place to start. So in doing so, I isolated and drained the boiler, fitting new sensors, repressurised the expansion vessel to 1 bar and filled the system to 1.3bar and put the boiler into P0 purge mode. F75 code gone but still no hot water or heating.
Right now to give some background, last year I replaced the diverter valve on this boiler due to a leak and went through a similar process of above. What I weirdly noticed was after the 20 mins of purge mode the boiler did this weird loop thing for a couple of hours of just running on and off with the green light on the boiler flashing until finally it settled, and started working as normal and gave me my heating and hot water.
A few months later as discussed in my other thread regarding 1 radiator not working. I drained the entire system and refilled and again purged the boiler which takes about 20 mins and then again the boiler went into some weird loop of turning on and off with the green light flashing for an hour and a half or so until it settled and started working as normal giving me my hot water and heating.
However now to the present day, after replacing the water pressure sensor and purging the boiler, it’s been in this infinite weird loop of turning on and off with green light flashing and it hasn’t gone back to normal. Yesterday I left in on for 6 hours in this way hoping it would settle, it did not, switched the boiler off and purged again thinking still air in the boiler, same thing after the 20 mins just in and infinite flashing loop. Today same thing. Checked the expansion vessel pressure, boiler pressure, bled the system but still no luck, still in infinite loop and no hot water or heating. I have taken a video of what’s happening so have a look at this link:
Cheers guys
Last edited:
