Siemens RDE20.1Room thermostat with 7-day time switch and LCD

These symptoms usually point to internal relay failure, water ingress, age-related component damage, or short-circuiting inside the controller. When this happens, the heating may either never start or never shut off, creating comfort issues and potential safety concerns.

Internal relay failure, moisture ingress behind the wall plate, age-related component fatigue, and internal short-circuiting require prompt professional inspection to prevent floor overheating or complete failure.

Our Solution – Instant Same-Day Replacement

Sparky G provides same-day replacement for faulty Siemens RDE20.1 units across Auckland. Our certified electricians can quickly diagnose the fault and install a modern, reliable thermostat.

Siemens RDE20.1 not turning off– underfloor heating stays on continuously

Underfloor heating overheating the floor

RDE20.1 display not working / unresponsive

Siemens thermostat shorting out

Underfloor heating not turning on at all

Burnt-out RDE20.1 controller

Old Siemens RDE20.1 stopped functioning

— THERMOSTAT REPAIR & UPGRADES

Is your Siemens RDE20.1 underfloor heating controller giving you trouble? Many homeowners experience recurring issues with older Siemens RDE20.1 units, especially as they age or develop internal faults. If your underfloor heating is not behaving as it should, we can help.

Our Auckland electrical team carries stock of compatible Siemens controllers for prompt, professional same-day replacement and underfloor heating diagnostics.

Same Day

Auckland Callout Service

Common RDE20.1 Faults

Direct Retrofit Upgrades

Full Sensor Testing

100%

Siemens Probe Compatible

Every replacement includes NTC floor probe resistance testing, insulation integrity checks, and a complete electrical safety verification by Sparky G.

Blank LCD screens, erratic temperature spikes, unresponsive buttons, or failure to trigger the floor heating relay are common signs of component fatigue.

We swap faulty RDE20.1 controllers with modern digital Siemens RDE100.1 units that fit existing backboxes and floor temperature sensors seamlessly.

Fast Same-Day Service

Heating Controller Specialists

In-Stock Thermostats

Get fast same-day electrical callout service across Auckland, subject to local availability, so your underfloor heating system is restored without delay.

Our NZ-registered electricians are experienced specialists in diagnosing and replacing Siemens underfloor heating controllers and modern digital thermostats.

We carry a wide range of compatible replacement thermostats directly in stock on our mobile service vans for immediate on-site installation.

Clean & Efficient Installation

Compliance-Focused Workmanship

Enjoy a clean, efficient replacement process with minimal disruption to your daily routine, complete with tidy work areas and respectful service.

Rest easy with compliance-focused workmanship, certified safety standards, and clear professional advice on operating your new heating controller.