The burner flange is neither the inlet or the outlet. It is the gasket between the boiler body and the flange to which the burner is fastened. On a boiler this old, it is quite possible you may need a new gasket and some high temp silicone to effect a good seal. You also need to ensure the...
I can't tell from your previous posts whether you have tried anothe photocell apart from the one fitted 3 years ago, that would be my 1st port of call. A failed coil would not cause permanent prepurge which is what you are getting. . Regarding the cut out when the burner cover is replaced, have...
60oC at 1/3rd the way up the cylinder can result in much higher temperatures at the top take off from the cylinder.
Any cylinder stat will be compatible but they are all quite coarse in there settings.
My thought is that the heat store stat and the boiler stat are out of sync, or there is an obstruction in the diverter valve that stops the boiler dispersing its heat. There used to be a similar problem with larger Mistral combis and they produced a mod that consisted of a clamp on button stat...
The black box sounds like a burner control box which has no effect on the boiler programming. There is not really anything you can do witout a multimeter and an understanding of the boiler circuitry. It could be a diverter valve head, or the P.C.B. or the programmer. does this boiler use the...
Do you get a humming noise when pressing reset? If so, then it may be a failed capacitor. It may also be a seized fuel pump.
Do you know whether you have a tiger loop fitted, or a one or 2 pipe fuel system?
£1350 may be a little heavy, but all parts are still available for B11 burners.
you say this is balanced flue, but is it actually a fanned flue that has a pressure switch in the flue. This is wired into the control box and can cause the problem you have. If you consult the wiring diagram for your particular cooker you will be able to identify any overheat stat and check its...
If you fully read the installation instructions for these valves, it warns you about this. The screws are significantly thinner than the mounting holes to allow for float.
as both Terry and I have both said, if the problem is with the post purge unit, then changing the burner will not saolve the fan running on problem. You need to feed the motor live feed direct from terminal 4, and disconnect the ppu conections and make them safe.