fuse blowing on Worcester 24i (old style version)

[tadpole123]

Hello hope someone can help me, my boiler works fine for hot water but when you try to put the heating on, it sparks from the timer and the fuse blows. Tried it 3 times now, so 3 fuses later any ideas?

It's in a cold damp north facing room with high humidity due to several fish tanks and the steam from cooking, tried a dehumidifier in the room just in case and 3 litres of water later, room feels dryer but that's it..was a bit of a long shot.

Is a new timer the answer? if so is there a cheaper version than the Worcester one?
Please don't tell me it's the circuit board, if it is, then it's electric heaters and move into one room, no money to pay for that to be installed, but a timer I could do myself.

 

[PrenticeBoyofDerry]

It certainly sounds like a fault with the heating control as this is when the fuse blows.
Does this circuit have RCD protection?
I ask this as this would normally operate (trip) before the fuse, if it were a moisture problem.
I would say from what you have posted a new control is needed.
Does this only happen when manually operated or does this also happen on the timed program?

 

[matt1e]

what make model of boiler is it?
as it is likely to be an external control wiring fault

especially this time of year due to xmas decoration drawing pins/tacks hammered into roomstat cables etc

Matt

 

[Agile]

I think the clue to boiler model is in heading!

Try powering the pump from an EXTERNAL mains plus fitted with a 3A fuse and turning it on first and then the boiler to CH and see what happens for a few hours.

Tony

 

[matt1e]

I think the clue to boiler model is in heading!

My second of the day

but since its one of those I'd say its definately an external fault

 

[tadpole123]

It certainly sounds like a fault with the heating control as this is when the fuse blows.
Does this circuit have RCD protection?
I ask this as this would normally operate (trip) before the fuse, if it were a moisture problem.
I would say from what you have posted a new control is needed.
Does this only happen when manually operated or does this also happen on the timed program?

Sorry *puts bimbo hat on* but is rcd the socket it is wired into that has as a fuse? if it is, then no, that hasn't blown but did replace just in case and it happens if manually operated and on timed.

*still wearing bimbo hat*....is the control unit the timer?

 

[tadpole123]

what make model of boiler is it?
as it is likely to be an external control wiring fault

especially this time of year due to xmas decoration drawing pins/tacks hammered into roomstat cables etc

Matt

no xmas decs up, or diy done

 

[tadpole123]

I think the clue to boiler model is in heading!

Try powering the pump from an EXTERNAL mains plus fitted with a 3A fuse and turning it on first and then the boiler to CH and see what happens for a few hours.

Tony

*bimbo hat back on again* no idea how to do that, but I'm sure google can tell me, is this safe for a 'bimbo trying not to be' to do?

 

[tadpole123]

I think the clue to boiler model is in heading!

My second of the day

but since its one of those I'd say its definately an external fault

A bimbo moment dont worry I have them too
How do I find out if it's an external fault?

 

[tadpole123]

3 different ideas or things to try, ideas please in which order to try them?

 

[Agile]

Its your choice!

But I would encourage you to do mine first.

Tony

 

[PrenticeBoyofDerry]

Sorry *puts bimbo hat on* but is rcd the socket it is wired into that has as a fuse? if it is, then no, that hasn't blown but did replace just in case and it happens if manually operated and on timed.

*still wearing bimbo hat*....is the control unit the timer?

This is a fuse connection unit(FCU), some come with switches some don't.

Untitled

• PrenticeBoyofDerry
• 11 Dec 2011
• 4

This is a FCU with RCD protection

Untitled

• PrenticeBoyofDerry
• 11 Dec 2011
• 5

This is a RCD that will be found at your Consumer Unit.

Untitled

• PrenticeBoyofDerry
• 29 Jul 2009
• 13

So the fuse is blowing back at the fuse board?
What size fuse is at the board that is blowing?
what size fuse is in the FCU?
The FCU needs to be down fused to 3Amp.

 

[tadpole123]

Thanks for the pics, my boiler is connected to the first one.

That fuse did blow a few years ago but that was due to overenthusiastic cleaning in the kitchen, it got wet from the spray bottle cleaning the tiles, water ran down the tiles and into it, took several days to dry out before it stopped blowing fuses

 

[algas]

As tony said the pump will be suspect, on this boiler it only works for the c/h so when heating is called for it blows the fuse, just change the pump head, probably grundfoss 16/60

 

[tadpole123]

The fuse that blows is on the circuit board?
The timer has a wire coming out from it and goes to somewhere on the left hand side where this little fuse is.
The board has 2 fuses but the other is fine....don't know what that ones for.

Anything involving that timer....put it onto constant, push the pins down so heating kicks in causes the little fuse to blow.
But the little sparks I see come from the timer unit.