Shower Prob: No heat - Electrical fault?

[griz]

I have just installed a new Creda Spray Spa 8.5Kw Electric Shower which won't work.

The power light does not come on. There is power on both sides of the power block in the shower which I tested with an electrician's screwdriver.

I don't think there is a problem with the water supply as I originally purchased another shower which is the type activated by a knob controlling the water flow. When the water flows the heater should come on. The water flowed through this shower but would not heat. I adjusted the water pressure + & - but to no avail. I returned this shower and got the above as a replacement.

The Creda has a "Stop/Eco/High" knob and a separate temperature knob. The water won't flow if the heat does not come on.

I don't think the PRV (pressure relief valve) has been activated because that area of the bathroom was bone dry before I fitted the pipework and remained so after completion.

The shower is on it's own circuit from the main board which has a 40A MCB, which has not tripped. There is a separate on/off switch with red neon indicator outside the bathroom. The cable is 10mm clipped to the wall/ceiling across the hall into the bathroom. The distance is approx 10/12m. The wiring is approx 25yrs old.

A pull cord isolating switch and RCD remain to be installed.

The previous shower failed with a bang. I can't remember if it was on at the time - I think not but I heard the bang. I usually turn on the shower leave it to warm up and then use it.

So. Is it possible that there is something wrong with the neutral or earth wiring? Do showers detect such problems and if it is electrical how do I go about checking and testing for faults?

Any help much appreciated.

many thanks

 

[griz]

I've just browsed through other posts about cable size.

The wiring is a cable that measures 10mm across. Is that the same as 10mm cable?

Regards

 

[electronicsuk]

I've just browsed through other posts about cable size.

The wiring is a cable that measures 10mm across. Is that the same as 10mm cable?

Regards

No. If it's 10mm in width, the cable you have is significantly smaller than 10mmsq. I would guess it is in fact 6mmsq, but depending on age and construction of the cable, it could even be 4mmsq.

If this is the case, it could offer an explain as to why your previous shower went bang (which may well have been the wiring rather than the shower) and why it refuses to work now.

Without even a basic test meter, there is very little you can do in the way of testing to start to narrow down the fault. As has already been recommended on the Electrics UK forum, you really need an electrician who's able to test insulation resistance, loop impedance etc on the circuit, as it sounds more likely to be a wiring than shower fault.

 

[ban-all-sheds]

I've just browsed through other posts about cable size.

The wiring is a cable that measures 10mm across. Is that the same as 10mm cable?

Regards

No. If it's 10mm in width, the cable you have is significantly smaller than 10mmsq. I would guess it is in fact 6mmsq, but depending on age and construction of the cable, it could even be 4mmsq.

Or even only 2.5mm² //www.diynot.com/wiki/electrics:flatpvccables

 

[electronicsuk]

I've just browsed through other posts about cable size.

The wiring is a cable that measures 10mm across. Is that the same as 10mm cable?

Regards

No. If it's 10mm in width, the cable you have is significantly smaller than 10mmsq. I would guess it is in fact 6mmsq, but depending on age and construction of the cable, it could even be 4mmsq.

Or even only 2.5mm² //www.diynot.com/wiki/electrics:flatpvccables

It would certainly explain the predicament the OP is in!

 

[griz]

Ok thank you. Message received and understood.


Oh by the way...

My last experience with an electrician was when a neighbour and friend changed her shower. Same brand same model but 9.5kw from 8.5kw. He was there 45 mins and of those 30mins were involved with changing the shower. The charge was £175 and...

No pull cord isolating switch was mentioned or installed;

No RCD was mentioned or installed;

No discussion took place about the wiring.


So you can understand why so many people are so uninformed about these things.

Still we live and learn or in this case we have lived and learn't.