Fuse keeps blowing

[james67]

Hello, i have a ideal classic balnce flue boiler, fully pumped but with a manual three port valve and programmer that just controls the pump. the heating hasn't been used for a few month, ive just been using the immersion heater.

Now this evening i switched the programmer from off to timed n it lit up but cut off straight away. i checked the fuse and this had blown, and now every time i put a new fuse in it blows.

Anyone have any ideas of what could be causing the problem? It's a new pump, about 6 month old.

 

[xr4x4]

You only need 1 post btw.

Have you checked the pumps spinning?

Unscrew sliver disk with pump turned off, insert a flat blade screwdriver and check that the pump impeller turns.

 

[james67]

Yeah the pump spins manually but obviously no power as fuse blows before pump gets chance to kick in

 

[bengasman]

Is it the fuse in the spur or in the boiler itself?
What amperage is the fuse in the spur?

 

[james67]

Its the fuse in the spur, and its a 3 amp.

 

[bengasman]

Turn the boiler off with the boiler switch and see what happens then

 

[james67]

Boiler switched off and still he same

 

[bengasman]

Most likely loose phase wire or damaged in the cable after the fuse to the boiler.

 

[gas112]

Check around your pump valves for leaks that may have dripped into the motorised valve or even a leak on motorised valve spindle this is usual cause for blowing straight away.
Easiest way for diy to check if its the pump is to disconnect wires and turn everything on if it dont blow its the pump if it does its more than likely the motorised valve

 

[james67]

Thanks for the help. I've disconnected the pump and still no joy. There is no motorized valve, its an ancient manual 3 port valve. The only things power by electric are the pump, boiler and programmer.

I've had some boards up recently, i'm starting to think that maybe ive nicked the cable as i have been refixing them, is this plausible?

 

[Boilerman2]

Ahhh! The "FULL STORY" starts to come out!!!
without a doubt a nailed cable!!

 

[james67]

Hello again, i found the fault and it was a damaged cable. ive replaced it and got the system up and running again. Thanks for all the help so far.

I now have another problem though, when i switch the fuse spur on the boiler fires up straight away then does not respond at all to the timeswitch. The only way to turn it off is at the fuse spur again.

Ive double checked and triple checked all the wiring i replaced and am sure its like for like. Is it possible that ive knackered the timeswitch?

 

[ChrisOxford]

Is it possible that ive knackered the timeswitch?

Possible but very unlikely.

It's MUCH more likely due to a wiring error... or another nail through another cable.

 

[james67]

Is it possible that ive knackered the timeswitch?

Possible but very unlikely.

It's MUCH more likely due to a wiring error... or another nail through another cable.

I haven't put the boards back down yet haha

 

[bengasman]

...Ive double checked and triple checked all the wiring i replaced ...

If it was working correctly before, then your replaced wiring is likely to be the culprit.

"Once you eliminate the impossible, what is left, no matter how improbable, is the truth"

S. Holmes.