What causes an F22 on a turbomax

[allenvb]

Dear all,
I am working on a turbomax, it has had the divertor changed, the flow sensor changed and the plate HE cleaned out. The heating is fine, but the HW runs hot, then goes cold and an F22 appears, would a new PCB cure this, as I have heard that the old software was a bit naff, but want to be sure before I blow the best part of £180. Also the boiler is stored outside in a carport, would this have anything to do with it?
Thanks in advance

V

 

[ColJack]

F22 is dryfire...
no water in the system or no water flow..

as the heating is fine and the water runs ou the hot tap then that rulses out frozen pipes i suppose, so it's the aqua sensor maybe?
broken lead to the sensor?
bad earth on the sensor?

 

[mickyg]

Who cleaned the plate he? are you sure its clear? is the pump ok? check the eye for dirt.

 

[allenvb]

Hi all,
stripped this boiler down again today, de scaled the Plate ex, cleaned and cleared the flow sensor (which is brand new) and the diverter (which is also brand new), cleaned the pump. Put it back together, it seemed to work, but then started to get worse in front of my eyes!!

One the boiler is pwered up or reset, the main burnr kicks in for round 30 secs, when a hw tap is opened, it fires up for around 30 secs, then the main burner goes out, but the fan continues to run, the only way to stop is to turn the boiler off or reset it. If the the tap is closed and opened again, the fan is still running, but it does not spark to ignite. Has this happened to anyone else, if so whats the cure? New NTC or PCB? or both?

Thanks
Vic

 

[Temprise]

Hi all,
stripped this boiler down again today, de scaled the Plate ex, cleaned and cleared the flow sensor (which is brand new) and the diverter (which is also brand new), cleaned the pump. Put it back together, it seemed to work, but then started to get worse in front of my eyes!!

One the boiler is pwered up or reset, the main burnr kicks in for round 30 secs, when a hw tap is opened, it fires up for around 30 secs, then the main burner goes out, but the fan continues to run, the only way to stop is to turn the boiler off or reset it. If the the tap is closed and opened again, the fan is still running, but it does not spark to ignite. Has this happened to anyone else, if so whats the cure? New NTC or PCB? or both?

Thanks
Vic

When these boilers first came out there was a problem with F22 faults and it was found to be a board problem.

But it would also depend on how old the boiler is as i am talking about the very early models. If its a later one then i doubt it will be the board.

Hve you checked and cleaned the auto bypass? If my memory serves me right i once had a bypass stuck open and gave me this problem.

Regards.

 

[Agile]

Have you done the finger test on the pump? ( See FAQ ).

Have you actually measured the temperature differential yourself ???

Have you measured the totally COLD resistance of the sensors?

Tony.

 

[Homesafe]

I had the same problem on my mum's turbomax F22 error's, min max will need checking and the min turned up a tad , it cured it for me.

You probably also have a small leak on the system somewhere which is reducing system pressure or has reduced system pressure to start this error code up.

mine will start up again now after this , diynot curse