Immersion cut out temp - Faulty?

Gary K · Oct 9, 2023

Hi All.
Its been ages since I have been on here- Fortunately log in details stored on PC.

I have just had a new boiler and 210 ltr unvented tank fitted in the loft to replace a very old Baxi back boiler. I have now fitted a Solic 200 diverter to utilise all the spare capacity from the 3,84 Kw Pv system on the roof. This has only just become an option as the old existing tank did not have an element fitted and I was told that the chances of fitting one to the old tank without damaging it were slim to none!

The issue that I have after checking the element fitted to just below the middle of the tank is that the thermostat appears to cut out a lot earlier than I expected. According to the manufacterers website, the element should when turned to maximum, cut out at 70deg/C, having a red tag although on the cover of my element, it states 65deg/C
As the sun is out today, I have had a bath rather than the normal shower and the water has been heating via the diverter for 90 mins or so and has taken 3.23Kwh of power but has now cut off due to the thermostat on the element.

Having done some very rudementary checking with a meat probe which does measure 100deg +/- when put in a boiling kettle, the hottest point on the hot water take off pipe and also under the nearest hot tap after running off some water is 50deg/C
Obviously, I have checked that the immersion stat is set as high as possible so would it be fair to assume that the thermostat is not acting correctly and is cutting out prematurely and would I have reasonable grounds to contact the fitters/ manufacterers and request a replacement element?View attachment 110936 View attachment 110937

brianmoooore · Oct 10, 2023

Not familiar with that immersion heater and 'stat at all, but since your original cylinder was installed the health and safety authorities have been hard at work, and now there are a host of new regulations that apply.
Stored hot water should be in the 60 to 65 degree range, and stats are now supplied without a calibrated scale, and with the adjustment locked in place by a blob of glue. There's also a secondary non adjustable stat included, pre set at a slightly higher temperature, and which may or may not be manually resettable. It is never automatically resetting.
Increasing the temperature of the stored water risks tripping this secondary stat - happens often when the water is also heated by wood burning stove or something like an AGA.
I don't think you'd get very far complaining to the manufacturer that you can't set the water temperature outside the recommended temp.
The maximum water temp from a hot bath tap is 48 degrees.

Gary K · Oct 10, 2023

Thanks for the reply.
And there is the issue - if water should be stored at 60 deg + , I have a problem if the adjustable stat is cutting out at under 50 when the specs state that it is adjustable to 60 deg/c Thats not high enough to kill legionaires desease. Obviously, using the boiler, I can raise the temperature higher but during the summer, I plan to completely turn it off and rely on the panels to heat the water.
The fitters have got to return to reconnect and certificate a gas fire so I will ask them to bring there own thermometer and we can make a decision based on their findings.

davesparks · Oct 10, 2023

Temperature issues aside the cable grip is missing from that immersion heater.

Gary K · Oct 10, 2023

Oh.
Missing from where?
I assume you mean something to grip the flex as in on a 3 pin plug. I haven't noticed anything spare lying around but can fabricate something. Looking at pictures of new elements, there doesen't seem to be anything supplied.

Gary K · Oct 10, 2023

I see now what is missing- on the side of the element. Will have a look and see if it has just not been used.

snowhead · Oct 10, 2023

Probably looked like this and was in the bag with the instructions

[ElectriciansForums.net] Immersion cut out temp - Faulty?

Gary K · Oct 10, 2023

snowhead said:
Probably looked like this and was in the bag with the instructions

View attachment 110960

Thanks.
I was going to say I must have the budget version as there is no clamp. but can see where the threaded hole is on the side.
I have a feeling that I chucked out the bag of rubbish but then again, the element was in the tank when it was unpacked so could be anywhere!

Gary K · Oct 10, 2023

Sorted.
Made a clamp with bits from the Garage

jay sean · Oct 11, 2023

Hot water has to be stored at 60C+ and water temperature at the taps should be about 50C, If I have been told by people at work who flush and sample our water that a house hot water tank is low risk