28CDi RSF (F1 Fuse Blowing)

Hi
Worcester-Bosch 28CDI RSF, 7 years old and only serviced twice in its life (yea, my fault but money always been an issue, man, save a little to spend a lot, when will I ever learn)
Yesterday the mains trip switch blew and left us in darkness, the cause was the combi boiler, the system was dead and I found that the F1 2 amp fuse had blown. I checked the wiring for damage and the system for leaks that may have caused a short on the circuit, including the board but none could be found, as dry as a bone. I fitted the spare fuse and all was ok, well for a couple of hours that is, then the mains trip switch went again, I switched it back on and everything worked, heating and hot water was fine but for safety reasons, and to ensure that my alarm clock remained active during the night I switched the boiler off at the mains. But today when I switched it back on, it ran for a couple of minutes, the boiler lit up and gave me enough time to get downstairs before the mains trip switch went again, this time the F1 fuse had also blown again, and I don’t have another, not yet.
I don’t believe that the issue lies with the circuit board as I think this would cause the fuse to blow as soon as the power to the boiler is turned on but it maybe the pump or extractor fan, could I be right? And if so what is the best way to find which is at fault?
I know the pressure valve needs replacing as I have to top up the pressure every two days and I did find two leaking radiators, both have been fixed but the valve I was going to do this weekend, but as usual things come in threes, bummer
Your help and thoughts would be appreciated, ha, as well as your criticism for not having it regularly serviced. Oh, and we all really need a bath real bad /:O)

In this case it is unlikely that a service would have prevented the fault.

However, a service by a conscientious engineer who can spell words with over 12 letters is always advisable during the quieter summer period.

Statistically its likely to be the pump or any other component where a water leak is a possibility.

Best way to check is to rewire the pump via a separate mains lead with a 3A fuse and run it independently 24 hrs a day and see if the boiler still blows its fuse or if the pump's new fuse blows.

Only try this if you are competent with electrical wiring. Agile has NOT encouraged you to tamper and a competent CORGI registered engineer is always the best option if anyone is to be electrocuted.

Tony Glazier

engineer who can spell words with over 12 letters

Click to expand...

I have noticed that it's around eight letters that you have difficulties...

I dont follow that!

The only misspelt word was "possibility" which has 11 letters when correct.

But as I had misspelt it there were only 10 letters. Its been corrected now but was originally spelt "posibility".

Whats got "8" letters?

Tony

Man, a service engineer who can spell a word with like 12 letters, now that something real special, in my line of work to find a field engineer who can spell anything over 4 letters and even recognise a multimeter is something to get exited about, like how sad is my job? /:O) ok Agile, I kinda feel competent enough to wire up the pump independently (man that like 13 letters, cool) with a 3 amp nail to break the circuit, if I can find one in my shed that is, will give it a 24 hour test over the weekend and see if I can run enough hot water to wash the scruffy urchins in the family, yea and the kids could do with a wash as well, thanks for the quick response and your advice peoples and will let you know how I got on
Cheers
Gingerbuoy /:O)