Ideal Classic NF40 tripping mains power

[wade74]

Hi, hope someone can help shed some light on this....

last night at around 10:30pm, the house consumer unit (a crabtree starbreaker) central on/off switch tripped, taking the house's power supply down. After a lot of investigation and resets, it was found to be down to the boiler.

The boiler in question is an Ideal Classic NF40.

The power to everything else could be brought back up fine, however when the boiler was switched on at the wall (not on the boiler itself), it was tripping the entire consumer unit.

Now it didnt cause the fuse on the wall switch to go, and it didnt cause the individual MCB with the heating (and power sockets) to go, just the entire consumer unit to go to Off.

I tried it several times over an hour or so, then settled in for a cold night... Tried it again 7am this morning, and it still tripped. Then tried it at 10:00 after examining the header tank..and its now working fine again..heated radiators and hot water fine since, and turned it off and on a good few times.

Noticed in the night - about 4am - that there was a lot of overflow coming one of the tanks in the loft, not sure if thats related...

So, any advice? The loft would have been damn cold last night, very cold up here in north yorkshire (not the bit that lost power) last night. But not sure if frozen pipes could cause what seems more like an electrical thing?

Hoping that its not suddenly going to go wrong again tonight! All advice welcomed.

 

[WDIK]

sounds like water may have splashed over a junction box or similar
do you know why an overflow was running?

 

[wade74]

Not certain about the overflow. However just noticed small pool of water underneath pump on hot water tank... guess the pump gets wet and it doesnt like it much!

Question is, wheres the water from...

looks to be same as...

//www.diynot.com/forums/viewtopic.php?t=89173

ugh...

 

[wade74]

ok update. Above the pump is a white box (or more correctly 22mm Mid Position Valve now i'm starting to get to know these bits!) with WMH on, and its dripping from the bottom of that.

Does this mean a replacement part is needed, or can i get away from tightening something??

 

[gas4you]

If tripping when boiler its self isolated then look at this zone valve head.

You have a leakage to earth causing an imbalance between L & N hence the RCD tripping rather than an mcb.

Disconnect the wiring to this valve and switch back on. If rcd does not trip it has proved it is this that is at fault.

If it's dripping then sounds like you need a complete new valve rather than just a new head.

 

[bengasman]

If it really causes the entire house to go dark, you have a pretty hefty problem with you fuseboard and/or wiring, and you would need a sparky to sort it out. I doubt this is the case though.
Where exactly does the water come from?
Can you post pics or leak and fuseboard?

 

[gas4you]

Not necessarily Ben. It will only take an imbalance of 30 milli amps to trip the RCD and if this is doubling up as the main switch the whole house will indeed go off.

So somewhere he has got >=30 mamps going to earth, could well be caused by the leak in the zone valve.

 

[twgas]

i would be looking at changing the three port, and quite possibly the pump if the water has dripped into its electrics

 

[bengasman]

537-03-02 would make it illegal to have rcd as mainswitch IMHO, though I must admit I find the wording about switching not particularly clear.
It does sound like RCD tripping though, maybe a tt with a 30 mA in stead of a 100?

Could we have pics of the fuseboard please? One close up and one including the meter and tails?

 

[gas4you]

I have come across several fuse boards that seem to have the RCD as the main switch also

Anyway, at least I now know how to write mA

Thanks Ben.

 

[bengasman]

And the secret is…………
Write in word with spell checker and even I can appear to be literate.



As long as we earn more than English teachers, all I care about is that people understand me, let them worry about spelling

As for coming across things that are common to see installed, I see plenty combis running on 15mm, does not make it good.

Electricity is not my strong point though, I am qualified, can design and test an installation and repair common faults. When it comes to the nitty gritty, I have to ask people.

 

[wade74]

Thanks for all replies above. Changed the mid position valve last night, after draining radiators with a bit of help from a friend who knows far more than me about this stuff! Seems ok now, not dripping and no power outages since..

Not changed pump, which so far seems ok, fingers crossed.