Heatwell has previously installed many Siemens RDE20 thermostats.  They are now very much obsolete.  Unfortunately, they have an annoying design feature of leaving the heating on when they break down (called a runaway thermostat).  A runaway thermostat must be replaced.

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Heatwell no longer carry any parts for the RDE20.  Our electricians are no longer able to come and fix any programming issues.

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Our current range of thermostats are the replacement for the RDE20.

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In the Auckland region we can arrange for our electrician to come and replace your old thermostat, and an electrical Code of Compliance (COC) will be issued.

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Our current range of thermostats are an easily installed replacement for an experienced electrician.  Our thermostats should not be installed DIY.

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Below are both an instructional programming video and a downloadable Instructions PDF.