DIY cylinder boiler/pilot light HELP!

[xzibit13]

I have a cylinder boiler which decided to leak, I have changed this to find my pilot light is off, and whenever I turned it on again, it turns itself off! Do I need to bleed the pump??Rads?? Does anyone have any ideas as to what could be wrong, and any suggestions?? I have no central heating or hot water!

[bubblebubble]

am i right in thinking that you have only replaced the cylinder due to it leaking? if so, no doubt you have drained all the water,and probably think (hope) that is is all full again! it sounds to me like your boiler heats up, then shuts down due to overheat ie. either air in the boiler or somewhere in pipe to tank. You should find that that the system is filled via the small header tank in the attic, if so does it have water in- if not may be ball valve stuck? so long as the water reaches the heating / coil in tank, it should be a question of bleeding. i would start at the highest point and work downward. if the pipes from your boiler do not go verticle you may well have an air pocket there-loosten a union at the highest point to bleed. does the pump appaer to be working? sometimes switching on &off will help to get the water moving too. good luck!

[buildersmate]

Once you have satisfied yourself that the system is full of water as above, if it still isn't able to light the fault would seem to be with the boiler. You say that you are able to get the pilot light lit, but then it goes out again. Does it go out before the main gas burners start up (main gas burners equals lots of blue flames visible through the little port hole)? Or do the main burners start up and then go off again quickly - say within 30 seconds? If it is the first of these situations then you have a problem with the boiler and will have to seek the advice from a CORGI plumber. These boilers have a fail-safe device on them so if there is no pilot flame, the main burners will not attempt to light. If it is the latter, then there is likley to be nothing wrong with the boiler but there is no water in the boiler heat exchanger and it is overheating quickly and turning off. The problem is as described by bubblebubble above.