Immersion thermostat with separate cutout

[Pretty Mouth]

Have just got back from a call out, where the clients' immersion had stopped working. The problem is the separate thermal safety cutout has failed open circuit, and cannot be reset. It is very similar to the setup in this youtube vid:

I would like to replace the thermostat with one with an integral safety cutout, and bypass the faulty separate cutout. I can't think of any reason why there might be a problem doing this, but I wanted to check with you guys and girls before I get stuck in.

Anyone know of any problem with this?

TIA

 

[loz2754]

Nope. Done it loads of times.

 

[Pretty Mouth]

Nope. Done it loads of times.

Great, thanks @loz2754 ???

 

[Dartlec]

Is it a Backer by any chance? As it happens I had one of these recently too - though someone had put a 'dual' thermostat in and not bypassed the safety circuit - which had failed...

You can actually get the replacement cutouts here if it's a Backer.

They make two types to meet the standard - one with the cutout button separately and one with it in the thermostat...

Since the thermostats that were in place were old and cheap in my case, I ordered the correct replacements just to match what was there originally...

Whichever way you do it, the outcome in either case is the same - main thermostat backed up with a backup one that will isolate the immersion before the water can go above 85 Degrees...

 

[Pretty Mouth]

Is it a Backer by any chance? As it happens I had one of these recently too - though someone had put a 'dual' thermostat in and not bypassed the safety circuit - which had failed...

You can actually get the replacement cutouts here if it's a Backer.

They make two types to meet the standard - one with the cutout button separately and one with it in the thermostat...

Since the thermostats that were in place were old and cheap in my case, I ordered the correct replacements just to match what was there originally...

Whichever way you do it, the outcome in either case is the same - main thermostat backed up with a backup one that will isolate the immersion before the water can go above 85 Degrees...

No, not a Backer. The thermostat is a Shel, so presumably the cutout is too. Can the cutouts be changed without draining the cylinder?

I have picked up a tesla replacement from screwfix, which hopefully should fit

 

[brianmoooore]

Can the cutouts be changed without draining the cylinder?

Thermostat just drops loosely into a tube. Top mounted one is 18" long, so you need a fair bit of space above it.
The separate cutouts just screw on, with a 4mm thread.

 

[Pretty Mouth]

The separate cutouts just screw on, with a 4mm thread.

As simple as that? Thanks.

Cheers for all your help guys ???

 

[timhoward]

As simple as that? Thanks.

Cheers for all your help guys ???

There’s a John Ward video where he pulls one apart btw

 

[Avo Mk8]

FWIW the failed part appears to be one of these:

Normally Closed Manual Reset Thermostats - Sinolec Components Ltd

Normally closed manual reset thermostats from sinolec.co.uk.

sinolec.co.uk

 

[Pretty Mouth]

FWIW the failed part appears to be one of these:

Normally Closed Manual Reset Thermostats - Sinolec Components Ltd

Normally closed manual reset thermostats from sinolec.co.uk.

sinolec.co.uk

Yes, that look like the one. Thanks, it's worth knowing where to get one for next time

 

[Avo Mk8]

Yes, that look like the one. Thanks, it's worth knowing where to get one for next time

But £6.77 by the time you pay shipping/vat ! ?

 

[brianmoooore]

All the ones that I've ever seen have been like the one with the stud on the bottom on the second page, but not with that temperature rating.

 

[Pretty Mouth]

An update in case anyone else comes across similar:

I tried the Tesla replacement thermostat, and it didn't fit at all - it had a very different shaped head to the original Shel one. I then tried removing the separate cut-out, with the intent of replacing that instead. It was held in place by nuts and a couple of small studs protruding from the base of the immersion heater. Anyway, one of the studs broke in the process, so that was that idea out of the window.

3rd time lucky, I got a Sunvic VKL 2351 with integral cut-out which has a very similar sized head to the Shel one, and fitted perfectly. Customer very happy!

Thanks again for the help.