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Reduce water heater operating temperature

About using this guide

This guide is designed only for the TDX120ERP

Increased water usage

By reducing the temperature of the water, you will use more hot water to get the shower/ bath to the same temperature that you previously enjoyed.

If you take short showers (and no baths) then I reccomend doing this, but if you have 2+ people that have long showers it's best to not bother


As the country I live in is an absolute Joke (Thanks Tory Government) - We are having an issue purchasing power, and thus the wholesale costs has gone up.

Recently it was identified that Heating the water was using around 43% of my monthly power bill.

Power off the heater

See Consumer unit, and turn off the switch labeled Immersion Heater

Open the Bottom cover


Ensure that the power is switched off from the mains before opening

Remove the Screw on the right hand side using a Phillips Screwdriver


Setting the temperature

We are able to set the temperature between the below values

Maximum Minimum
68°C (154.4 freedom units) 12°C (53.6 freedom units)

Once the cover is open, locate the Thermostat.



Familiarize your self with the below diagram.

Turning to the left will decrease the heat

Turning to the right will Increase the heat


Turn the screw towards the left

You will hear a slight click noise as you go to the left. That will be the original heat setting.

Turn the screw towards the right

Additional Information


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