Problem with Gledhill immersion element burning out

[Melter]

We had a new bathroom installed about 15 months ago and with that came a new Gledhill Stainless Lite tank. In that time we've had to call the plumbers and electrician out 3 times because the main element keeps burning out.

The plumber initially thought it was a wiring problem because the end that connects to the element keeps melting. On this last occasion our electrican got to see the removed element and he thinks it's a fault with the thermostat. You can see where the plastic casing has melted and he says the cable is more than adequate for the job.

The issue now is that on the previous two occurences we weren't billed by the plumber but now we have been and we don't believe this is something we should be paying for. Our electrician hasn't charged us a penny for any of the work.

I've had a look at the Gledhill guarantee and it says they cover components for two years from date of purchase but it's not clear what they term as components.

We don't want to fall out with our plumbers over this because they've always attended to the problems straight away and did a really good job on the install. So any suggestions on what our rights are here or who's responsible for the fault will be gratefully received.

Picture of the offending item below.

 

[Hugh Jaleak]

Sparks may have a better idea, but i'd hazard a guess the cable is not making sufficient contact with the terminals and arcing. For that to happen repeatedly though would be unusual, but if the plumber has been connecting the wiring up then its possible. Cable may well be heavy enough for the job, but if it isn't making full contact at the terminals then it will arc, 3kW immersions will draw around 13Amps when working.

I'd get the stat replaced, and ask your electrician to check it or preferably wire it up and see what happens. Cant see you have any claim against Gledhill, its an installation issue, not manufacturing fault.

 

[Nige F]

the main element keeps burning out.

Is it the main element or just the thermostat that keeps burning out - ie. does the tank have to be drained to replace the main element - each time

 

[simond]

It looks to me like the immersion heater may be drawing excessive current and arcing out the thermostat.

The electrician should have either measured the current with an ammeter or a clamp.

If it isn't this, then you could have a duff batch of thermostats. To be honest, most of the new ones seem shoddy, its not at all unusual to find a burnt one open circuit.

 

[matt1e]

looks to me like the terminal hasn't been tightened sufficently enough, thats a classic sign of a "loose connection" probably caused by using a driver too small for the job

Matt

 

[Melter]

the main element keeps burning out.

Is it the main element or just the thermostat that keeps burning out - ie. does the tank have to be drained to replace the main element - each time

Hard to say. The first time it happened the element was replaced. The second time the plumber noted the wire had melted and just stripped it back and it was working again. This last time the plumber saw that the wire and the thermostat had burnt out and just ordered a new element. He said to get our electrician back to check the wiring and to wire up the new element once installed, which he's done. Our electrician changed the cable as a precaution and looking at the burnt out thermostat that the plumber's left this time he thinks possibly the relay(?) isn't switching over properly. It's interesting to hear that the latest thermostats are of poor quality because it backs up what the electrician's been saying throughout this.

 

[Nige F]

[quote="Melter";p=" It's interesting to hear that the latest thermostats are of poor quality because it backs up what the electrician's been saying throughout this.[/quote] Well, we are Trading Partners with China now

 

[Agile]

As Matt says that is a classic example of terminals which have not been properly tightened.

I find that twisting stranded wire is also important.

One thing that I note is that the plumber seems unable to wire up the immersion heater.

After a connection has been arcing its always necessary to cut back the cable to expose new wire.

The voltage and current need to be checked and nothing you have said indicates that has been done by anyone.

I also agree that many of the current carrying components are not very well sized to carry the current. Just compare the size of conductors on commercial components where thick copper is used and not thin brass.

Its not always appreciated that as well as carrying the current the terminals have to conduct heat away from terminals which always have a higher resistance than a continuous conductor.

I hope that you have not been covering the immersion with anything? They must be kept out in the open with a free cooling air flow.

Tony

 

[Melter]

Ok couple more questions.

Can the thermostat be changed without removing the element? i.e. Does the image I posted show the thermostat and element or thermostat on a rod that slides into the element?

How much does a new element cost (not installed)?

 

[Agile]

That pictured thermostat is easily changed and takes about 10 minutes.

I THINK that the Gledhill uses standard immersion heater elements which cost about £30.

Fitting is another matter as the cylinder has to be drained and that takes quite a while.

I now charge £152 inmcluding the new element if its a lower element. A bit less it its a top element which needs less draining.

When changing elements I look inside the cylinder to see the condition.

Tony

 

[Melter]

Thanks for that. Think I've got enough info now to put together a letter back to the plumbers stating our position. Probably on a hiding to nothing but got to try. Cheers.

 

[mickthemiller]

That pictured thermostat is easily changed and takes about 10 minutes.

I THINK that the Gledhill uses standard immersion heater elements which cost about £30.

Fitting is another matter as the cylinder has to be drained and that takes quite a while.

I now charge £152 inmcluding the new element if its a lower element. A bit less it its a top element which needs less draining.

When changing elements I look inside the cylinder to see the condition.

Tony

Tony,
I have been having the same problem,3 burnt out elements in the last 20 months,one has just gone today,I note that you say that you look inside the cylinder at the condition,what are you looking for ? My problem seems to be the thermostat not turning off or working properly,I do get very hot water which is wrong IMO but I left the stat on the factory setting,no burning in noticable on the wiring,this is starting to bug me know

 

[Agile]

Talking about short horizontal elements fitted near the bottom, its important that there is plenty of water below them.

Sometimes the cylinder has about 150mm of lime scalings in the bottom. If these are so deep that it prevents water flow the element will overheat.

The thermostats should be adjusted to give a temperature between 55-60 C.

I have never had a problem with any immersion that I have fitted but go to many with overheated connections!

Tony