No power to immersion

[HappyHippyDad]

Morning all.

I have just been to a house where there is no power to the 13A FCU feeding the immersion.

I believe I have found the corresponding MCB in the CU although it is difficult to be sure as there is only continuity on the CPC, it is labelled water heater. There is no continuity from the CPC in the FCU to any other CPC's in the CU which also makes me think I have located the correct MCB.

It has not been working for around 6 months. The tenants say no work has been carried out and it just stopped working one day.

It does seem odd that there is a completely clean break between line's and neutral's (L-L >999Mohms, N-N >999Mohms) of the cable and the CPC is intact, barring any parallel paths (unlikely).

I have searched everywhere for a DP switch or timer switch but cannot find one. The tenants say there isn't one and the landlord is unsure.

Am I missing something obvious? The reason I ask is because I will be putting a new circuit in (easier than taking carpets/floorboards up to find fault) but it just seems like there must be another switch somewhere and that's a lot of disruption for the sake of flipping a switch!

 

[telectrix]

had somewhat similar recently. there was a 20A D/P switch in the kitchen. customer used to leave the FCU in the airing cupboard permanently on and use the kitchen switch. the fault was O/C pole in this switch.

 

[snowhead]

Is there a switch in the kitchen, used to be common.?

 

[DPG]

Has the tenant done any DIY etc (not electrical) but doesn't want to admit it?

 

[Baddegg]

Had the exact same thing with an extractor fan @happyhippydad, the homeowners was adamant there was no switch, so checked everything and informed them either there’s a switch or something has cut through most of the cable and the only way to find it was to start ripping up the kitchen floor......turns out there was an isolator switch (at foot level for some reason) behind a shoe box! ?

 

[HappyHippyDad]

There is a gas boiler in the kitchen which has a FCU and there is also an old timer switch which looks linked to the boiler controls but this is on the ring circuit so I have disregarded it as I cant see how it has anything to do with the immersion. I wish i'd taken pictures!

 

[Lucien Nunes]

Time to invest in a cable tracer?

 

[HappyHippyDad]

Has the tenant done any DIY etc (not electrical) but doesn't want to admit it?

Perhaps, but they say they haven't.

 

[davesparks]

As mentioned above there was a trend for putting an immersion heater switch in the kitchen at one time, I think it was the 80's.

Ive had a few easy jobs being called out by a plumber for a non-working immersion and all I've had to do is switch it on in the kitchen.

 

[Baddegg]

Perhaps, but they say they haven't.

I’ve never met one that admits to that straight away ?

 

[HappyHippyDad]

Time to invest in a cable tracer?

Can these tools detect under floorboards and through carpet? Are they accurate?
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As mentioned above there was a trend for putting an immersion heater switch in the kitchen at one time, I think it was the 80's.

Ive had a few easy jobs being called out by a plumber for a non-working immersion and all I've had to do is switch it on in the kitchen.

I think I will advise a revisit to have a proper hunt in the kitchen. It's a very cluttered house unfortunately.

 

[Baddegg]

As mentioned above there was a trend for putting an immersion heater switch in the kitchen at one time, I think it was the 80's.

Ive had a few easy jobs being called out by a plumber for a non-working immersion and all I've had to do is switch it on in the kitchen.

Had one the other week where the plumber had removed the immersion for a combi boiler, the switching arrangement for the original set up was two single pole switches one for on/off and one for sink/bath and rather than install a new double pole switch for isolation he ran the neutral through one side and the line through the other side.....the fella tiling the kitchen messed up the switching arrangement ?

 

[buzzlightyear]

think I will advise a revisit to have a proper hunt in the kitchen. It's a very cluttered house unfortunately.

would you like me to look for you, I love treasure hunting, got me metal detector and a axe. Lol

 

[Lucien Nunes]

Can these tools detect under floorboards and through carpet? Are they accurate?

Yes, although not generally through anything conductive like foil. Accuracy depends on skill and creativity of user.

One trick that might be worth 2 minutes is a resistance test and then an insulation test L-N back from the FCU input towards the CU. If the resistance test shows O/C but the insulation test shows a few hundred kilohms, you know you're looking for a switch because you've found its neon indicator.

 

[multimick]

Seen it before where switch is at back inside cupboard .customer loading tins of beans into cupboard has caught the switch

 

[littlespark]

We had a kitchen switch at my parents for immersion in a 70’s house.... now disconnected, hidden by a fridge freezer and there’s no immersion tank anymore....

is next door neighbour the same style of house? Maybe have a look in their kitchen for signs of a switch. Might be in same place??
(Optimistic)

Are you sure it’s an FCU at the tank? The 13A fuse will go regularly on a 3kW heater.

6 months without hot water?

The timer switch you mention.... is it an old e7 quartz? Or is it a proper central heating programmer?

 

[Mike Johnson]

I have problems remembering what I did a week ago let alone six months and they say no work has been carried out?

 

[DPG]

would you like me to look for you, I love treasure hunting, got me metal detector and a axe. Lol

If I had to guess which of the forum members had an axe, it would have been you Buzz

 

[Baddegg]

If I had to guess which of the forum members had an axe, it would have been you Buzz

I have an axe as well....?

 

[Mike Johnson]

I'll raise you a chainsaw.