F22 error/ low pressure

Cannot find the fault code . There are vidoes on u tube saying how to reset thr code By pressing the reset button . If this does not work youcan ccontact vaillent on there web page . I have a mate who works for them i will ask him as well

you might have a small cold water leak

USE A ELECTRIC METER AND CHECK FOR 120 VOLTS AT CIRCUIT BOARD AT LINE IN AND COMMON , IF YOU DO HAVE 12 0 VOLTS THE LOOK FOR TAPPINGS FOR 24 VOLT OUT PUT MAYBE A BAD TRANSFORMER OR CIRCUIT BOARD

I take it this is a Vaillant EcoTec boiler? If your having to pressurise to 2.0 before the F75 goes, there's a strong probability there's a problem with the water pressure sensor. These can sometimes just have dirt/sludge in them, and can be cleaned, however a lot of the time they just need to be replaced. F75 can also mean there's a circulation problem through the boiler, and you will get the same fault code. If you have the old rubber hoses on the flow and return pipes, these can be prone to blocking/restricting and Vaillant have actually modified this part whereby by the pipes are solid copper.

try to enter here all informations and you can find the manual: http://instructions-manuals.com/search.php?cmarque=VALLIANT%20&modele=ECOTEC%20PLUS%20824

Hi Guy's,
The answer is that your system is out of water pressure.
Usually there is a nob on the right under the base of the unit near to the small dial to the right of the front cover.
To enable the system to work correctly the needle on this dial should be in the Grey, about midway position.
Currently with fault F22 this will be lower to below the Grey and on the needle.
To bring the pressure back to the correct position, you need to turn this nob until you hear the water entering the system, KEEP AN EYE ON THE DIAL AND TURN THE WATER OFF AGAIN WITH THIS NOB ONCE THE DIAL IS IN THE CORRECT GREY POSITION AS MENTIONED ABOVE. DO NOT OVER FILL THE SYSTEM. I suggest you check this every six months or so.
Once this is corrected your unit will light up again.
Best of luck. Mike. N.