Immersion Thermostat wire burns out

[marconi]

Can you provide a link to this info? I'd like to share it with the supplier.

I will see if I still have it.

 

[marconi]

Cotherm TSD01106 Thermostat - 280mm Stem, 20AMP | eBay - https://www.ebay.co.uk/itm/183661179944

It was this company advertising on ebay to sell the control stat that included the advice I pointed out in red. Perhaps email or call them for further information. If you learn more from this company on why the advice was given would you mind sending another post so others can know too please?

Regards
Marconi

WH (Water Heating) Co Ltd
Trevor Guy
2 Horsecroft Place
Harlow
Essex
CM19 5BT

Phone: 01279641722
Email: [email protected]

 

[johntheo]

Total resistance was measured at 14 ohms so 3 elements in parallel = approx 42 ohms/element but total current through stats is still the same, "4kw" immersion is 3.779kw @ 230V = 16.43A. or 4.114kw @ 240V = 17.14A so new stat is just doing what it's supposed to do and not burning out?. (single phase supply).

 

[brixtonia]

Wrote to supplier who replied:

The thermostats are designed for single phase elements, or three phase elements wired in single phase configuration up to 4kw.
To use with elements wired in three phase configuration, the thermostat needs to switch a contactor.
So, the thermostat you received with your 4kw element is suitable for single phase use.
The 4kw element is rated at 17.5a and the thermostat is rated at 20a.
We have never had a thermostat burn out. Please check your wiring as the problem is not with the thermostat.

However, it seems to contradict the instruction leaflet (not received with the immersion - emailed after) which seems to say that higher loadings than 3kW need a contactor?

 

[Avo Mk8]

I'm suspicious of the binary pricing of the Cotherm thermostat in the marketplace - around £12 general outlets, around £30 from reputable suppliers, one of whom publishes this footnote with the details of the stat:

SANTON S8203 THERMOSTAT TSD01106 11" 5-80'C COTHERM
This part is compatible for use with:

• Santon DF range R25/R45/R70/R115

PLEASE BE AWARE: This a genuine Heatrae Sadia manufactured part, unlike many of our competitors.

The genuine part seems to have a 'properly approved' 20A resistive rating, so I would have thought capable of handling the 4kW load. Perhaps your leaflet covers the, dare I say, " Chinese Export" version