Fitted as standard with our immersion heaters.

All of our domestic immersion heaters are fitted as standard with an RDT combined thermostat and resettable safety cut-out.  Our RDT resettable thermostats provide a further level of protection against boiling to steam, to achieve compliance with BS EN 60335-2-73 standards, without the need to drain down the hot water cylinder.

Our RDT resettable thermostats have an adjustable temperature range from 10°C to 60°C, but are factory pre-set to the maximum 60°C for normal operation to safeguard against harmful water borne bacteria such as Legionella.  Our thermostats have a manual reset which incorporates patented MFS technology to ensure single pole safety operation.

Product safety assured

Safety cut out

Factory tested

Fully factory tested for reliability, quality and safety

  • Adjustable temperature range from 10°C to 60°C
  • Factory pre-set to 60°C
  • Manual reset feature incorporating "MFS Technology” to ensure single pole safety operation
  • 7" for horizontal installation, 11" either for horizontal or vertical installation, 18" for vertical installation only
  • Two year warranty (product parts only)

  • thermostat

View product specification

When clicked this will open the product specification in PDF format.

RDT resettable thermostats


Order Code




RDT 7 "



RDT 11 " (Horizontal)



RDT 11 " (Vertical)



RDT 18 "



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At Heatrae Sadia we understand that you should never put a price on comfort. Our products are designed with the highest quality of materials and we lead the market with our engineering expertise. Whilst we don't sell our products direct to the trade, we are the only leading manufacturer to have our entire product range stocked by all the leading merchants.
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