Immersion Heater Stat Locking Out

[old wrinkly]

I recently had a Euralloy Titanium 3KW 27inch immersion fitted to my new Gledhill Envirofoam Stainless Steel Hot Water Cylinder. Initially everything worked fine but then after about 3-4 days I found that the thermostat had locked out. Did a reset and it workd fine again for a few days then did the same thing again. After several lockouts I went back to the retailer and they provided me with a new stat (Backermatic) and a replacement 27 inch Titanium immersion (Thermotec Ltd) & stat (Backermatic). They suggested replacing the stat rather than the whole unit and see how things went.

Fitted it last Wednesday and again everything seemed OK but this morning the new stat has locked out and needed a reset. The temperature setting for the new stat is fixed, as there is a blob of white sealant/wax on the actual dial to stop any adjustment.

Spoke to retailer but they aren't able to offer any guidance as to what might be the cause, other than perhaps a power surge, and suggested I contact my plumber.

The immersion is run via Greenbrook 7 day digital timer to take advantage of Economy 7 electricty.

Anyone got any clues as to what might be happening?

I should mention my wife is aware of not covering the lid of the immersion with clothing etc.

 

[Agile]

It is not possible for me to say whats wrong without measurements!

I would want to know the applied voltage at the element, the current taken and the temperature of the cylinder ( probably measured at or near the top ).

I have not previously encountered an immersion heater with no temperature adjustment. Did the installation instructions comment on that and say what temperature it was set at?

Tony

 

[old wrinkly]

Hi Tony

Thanks for your reply.

Since my original posting I have managed to find the address of the immersion heater/thermostat {Tesla UK Ltd) and I have spoken to them about the problem.

Apparently there is now a requirement for all immersion heater thermostats to detect the ambient temperature in the "airing cupboard" and once this reaches 70 degrees fahrenheit the cutoff kicks in. Seems they get calls about this on a regular basis. As the guy said if he'd had a £1 for all the calls he would be a rich man.

The solution offered is to cut a hole in the celing of the cupboard and vent to the loft or vent the doors so there is through flow of air.

At the moment, at their suggestion, I am running the immersion on the timer but with the door propped open.

Have you ever heard of this requirement?

 

[picasso]

I think the bloke from tesla is talking nonsense, 70f is 21 c and you wont find many airing cupboards ambient temp under 21c, immersion heater stats are cheap so I dont think there will be another ambient temp stat built in, probably just another crappy chinese product not fit for purpose.

 

[Agile]

It has been normal to use Centigrade measurements since about 1965.

Anyone who is quoting Fareignheit temperatures now does not sound credible. As stated 70F is room temperature. Perhaps it was 70 C and it is you who made trhe mistake?

He may have a kind of point, although I have never seen any whyich actually sense the room temperature although the surrounding temperature has an effect on their operation.

Now the salient question! Is your cylinder a bare copper one rather than a proper foam lagged one?

Tony

 

[Terrywookfit]

The safety limit stats are a pain in the arris,when fitted to heaters in the top of the cylinder.
Far better to use the side mounted ones to avoid thermal stratification and nusiance tripping.

 

[old wrinkly]

Thanks for the replies.

Just to clarify a few points:

No I haven't mistaken 70F for 70C (158 Fahrenheit). at 158F I think I would have noticed the heat in the cupboard and most things in it would have melted (including me) or been dangerous to touch.

Tesla (UK) Ltd are a reputable company based in Birmingham with all the necessary certifications.

My Hot Water Cylinder is, as stated, a stainless steel fully foam insulated Gledhill Envirofoam.

The Gledhill does not have any facility for a side mounted heater.

This is an extract of the latest reply I received:

EN 60335-2-73 is the new standard. In the old days there was no safety circuit so if the Thermostat went open circuit it would just continue to heat the water until it boils. At that point it flows back up the expansion pipe to the header tank which is normally plastic. That produces catastrophic results as 2 people have died from burns after the tanks gave way due to melting and crashed through the ceilings into bedrooms below causing over 90 degree burns to the victims who subsequently died.

I have no technical knowledge so have to be guided by what the manufacturer, in this case, Tesla tell me.

As I said I am now testing the heater temporarily with the cupboard door left ajar and if, as they have stated, this solves the problem then I will make the necessary permanent alterations to provide air flow.
[/b]

 

[gremlin16]

I have not previously encountered an immersion heater with no temperature adjustment.

Quite a few manufactures preset their stats to 60c and are placing silicon blobs to prevent the dial turning.
To adjust stat just remove the blob.
Problem then is supplier refuses to exchange them if faulty, tw&t.