Cotherm TDSR1802 immersion heater thermostat help - is the red circled area the reset button?

[Deee]

 

[Scally-Ho]

It could be as nearly all have one somewhere. The only way to be sure is depress it and see what happens.

 

[ericmark]

Not all are resettable. The reset is so if an alternative form of heating, like a back-boiler, overheats the water, then the unit can be reset, same where two immersion heaters are in the same tank, but where it is the only water heater, it was felt that it is better if it overheats for whole unit to be changed.

It comes down to the use of thermoplastic, rather than thermal setting plastics for the header tank. This

it seems can be the result read more here and there was a knee-jerk reaction and for a time most were non-resettable. Then it was realised, back-boilers could activate the cutout without the immersion heater even being switched on, so then we went for the resettable type.

 

[Deee]

Not all are resettable. The reset is so if an alternative form of heating, like a back-boiler, overheats the water, then the unit can be reset, same where two immersion heaters are in the same tank, but where it is the only water heater, it was felt that it is better if it overheats for whole unit to be changed.

It comes down to the use of thermoplastic, rather than thermal setting plastics for the header tank. This View attachment 384959 it seems can be the result read more here and there was a knee-jerk reaction and for a time most were non-resettable. Then it was realised, back-boilers could activate the cutout without the immersion heater even being switched on, so then we went for the resettable type.

Thanks for this. What an awful, sad tragedy. This kind of rings familiar. A few years back (same property as now) i noticed that my toilet cistern was filling with hot water. Turned out that the single immersion element thermostat had indeed "gone" and the cold water loft tank was taking the overflow of hot water. I live in rented accommodation and its a bit concerning that at that time of thermostat replacement (definitely after 2008 -the date of the news article) no independent safety cut out device was also fitted, nor does the system as a whole get checked at any time.

 

[flameport]

That may be a reset button, however if it has activated then the thermostat has failed, so the whole thing will need to be replaced.

Resetting it might get you one lot of hot water before it opens again.

 

[ericmark]

I had a 9-inch immersion heater in my tank, with a 7-inch thermostat which had tripped, reset it, and tripped again, so set to around 50ºC, and it seemed to work OK, but on my to-do list.

So swapped the thermostat, and it worked for a time, but a terminal overheated, maybe I had not done it up tight enough, or the screw had a stray wire as no ferals were used, but 9 inches were too short anyway, so got a plumber to fit a 27-inch version, and the hot water is so much better.

This seems strange, why should we seem to get hot water to taps faster? I now question the whole idea of a 9-inch, 3 kW immersion heater, if the 27-inch is 3 kW then the 9-inch should be 1 kW to get the same water movement within the tank. Maybe having a senior moment? But it just seems 3 kW with such a short immersion is asking for problems.

I said to plumber likely like that from new, answer was no, it came out too easy, and then he found the original 27 inch clearly failed under the tank, so I wonder why a 9-inch one was fitted?

 

[SUNRAY]

I had a 9-inch immersion heater in my tank, with a 7-inch thermostat which had tripped, reset it, and tripped again, so set to around 50ºC, and it seemed to work OK, but on my to-do list.

So swapped the thermostat, and it worked for a time, but a terminal overheated, maybe I had not done it up tight enough, or the screw had a stray wire as no ferals were used, but 9 inches were too short anyway, so got a plumber to fit a 27-inch version, and the hot water is so much better.

This seems strange, why should we seem to get hot water to taps faster? I now question the whole idea of a 9-inch, 3 kW immersion heater, if the 27-inch is 3 kW then the 9-inch should be 1 kW to get the same water movement within the tank. Maybe having a senior moment? But it just seems 3 kW with such a short immersion is asking for problems.

I said to plumber likely like that from new, answer was no, it came out too easy, and then he found the original 27 inch clearly failed under the tank, so I wonder why a 9-inch one was fitted?

What he had on the van