Mikuni, mx40 Keeps blowing the 25amp fuse?????

[Kristian]

Ive just noticed that my heating went off, so went to check the boiler (Mikuni mx40) and found the clear 25amp fuse had blow.

No major issues or so I thought so popped in a new fuse, and guess what? As as it began to fire up a small pop was heard and found the fuse

had blow again! Bugger!

Has anybody any ideas??

Many thanks Kristian.

ps it was only serviced 6 months ago so is nice and clean inside+new plug etc!

[GUMPY]

Ive just noticed that my heating went off, so went to check the boiler (Mikuni mx40) and found the clear 25amp fuse had blow.

ps it was only serviced 6 months ago so is nice and clean inside+new plug etc!

I assume you mean the Mikuni fuse and not one that has been put in the supply line by an installer.

Depending on use six months could be a long time.

Have you checked the plug sice the fuse blew?

As the 25amp fuse feeds the glow plug then the only thing that will take out the 25amp fuse is a shorted glow plug, If it is that then you will need to clean the swirl holes when you replace the plug see this thread for details

http://www.canalworld.net/forums/index.php...c=13832&hl=

 

There are 3 fuses in the syetem one feeding the glow plug (25A) one for the air motor (7.5A) and one for the water pump (1A), there should also be a supply fuse somewhere else as well.

 

Julian

[Kristian]

Thanks for your fast reply Julian, Its the fuse in the supply line that the builder put in that keeps blowing!

Looking at the manual, It could be "Water pump seized" Due to frost/damage. But I doubt this as it stopped working when it was running, plus theres antifreeze in the system!

It could be the glow plug thats blow and the damaged element is shorting things out!

The book go's onto say "Motor blower"/Bearings damaged! But again this seems odd due to it running proir to blowing!

So god knows!

Will let you know!

Kristian.

[GUMPY]

Thanks for your fast reply Julian, Its the fuse in the supply line that the builder put in that keeps blowing!

Looking at the manual, It could be "Water pump seized" Due to frost/damage. But I doubt this as it stopped working when it was running, plus theres antifreeze in the system!

It could be the glow plug thats blow and the damaged element is shorting things out!

The book go's onto say "Motor blower"/Bearings damaged! But again this seems odd due to it running proir to blowing!

So god knows!

Will let you know!

Kristian.

As in previous post both the water pump and the air motor are on their own fuses which would blow first.

It can only really be the glow plug.

 

J

[Tommo]

Ive just noticed that my heating went off, so went to check the boiler (Mikuni mx40) and found the clear 25amp fuse had blow.

No major issues or so I thought so popped in a new fuse, and guess what? As as it began to fire up a small pop was heard and found the fuse

had blow again! Bugger!

Has anybody any ideas??

Many thanks Kristian.

ps it was only serviced 6 months ago so is nice and clean inside+new plug etc!

 

 

It's almost certain that it will be the glow plug.

 

Ian

[Kristian]

Yes your right, My penny has just dropped, both other fuses are well below 25amps so would blow first!

Ill have a look during the morning! Just seems odd as its (meant) to be a new plug, 6 months old and is only on for a few hrs during the morning and a little

during the odd evening!

Will let you all know!

Thanks very much Kristian.