Description
Control High-Load Underfloor Heating from a Single Thermostat
The ThermoSphere Contactor Snubber lets electricians control electric underfloor heating systems with a total load over 16A from a single thermostat. Once the connected load exceeds the maximum switching capacity of a standard thermostat, a contactor snubber steps in to safely switch the higher current while protecting the thermostat's relay from arcing and premature wear.
Key Benefits
- Allows one thermostat to control high-load underfloor heating systems
- Snubber circuit protects the thermostat relay for a longer service life
- IP30 rated and double insulated, safe for home and commercial use
- Available in 25A, 40A and 63A ratings to suit the size of the job
Applications
Specified by electricians and underfloor heating installers on larger domestic and commercial installations — extended kitchens, open-plan living spaces, multiple bathrooms or large tiled areas — where the total connected heating load exceeds the 16A a standard thermostat can switch directly. Surface mounted alongside the consumer unit or heating control circuit.
Performance & Features
Rated for 230V supply and housed in a robust, double-insulated IP30 enclosure suitable for safe indoor use, the ThermoSphere Contactor Snubber switches the full heating load while being triggered by the low-current signal from a standard thermostat. This keeps thermostat components within their rated switching capacity, reducing wear and the risk of relay failure on higher-power systems.
Compatibility
Compatible with all ThermoSphere thermostats and electric underfloor heating cable, mesh and foil systems. Choose the rating (25A, 40A or 63A) to match the total connected load of your heating circuit.
All electrical work should be carried out by a suitably qualified electrician in accordance with the relevant local safety regulations and standards. ThermoSphere is backed by Millcot's trade support — buy with confidence from a specialist UK underfloor heating and tiling supplier.
Key Features
- Enables single-thermostat control of high load heating systems
- Snubber protection for the thermostat relay
- IP30 rated, safe for home use
- Double insulated for added safety
- Surface mount enclosure
- Available up to 63A maximum load
Technical Specifications
- Power supply: 230V
- Size: W 110 x H 180 x D 95mm (all ratings)
- Protection rating: IP30
- Mounting: Surface mount
- Double insulation: Yes
- Load ratings available: 25A (CSN-025), 40A (CSN-040), 63A (CSN-063)
- Country of origin: Germany
- Warranty: 3 years
What's Included
Each unit supplied is one ThermoSphere Contactor Snubber in your selected load rating (25A, 40A or 63A), ready for surface mounting and wiring by a qualified electrician.
Downloads
FAQs
When do I need a contactor snubber?
If the total connected load of your electric underfloor heating exceeds 16A, you can't switch it directly from a single thermostat — you'll need a contactor snubber rated for your total load.
Which rating should I choose?
Select 25A, 40A or 63A based on the total connected load of your underfloor heating circuit — add up the wattage of all connected elements and convert to amps, or ask your electrician to confirm.
Is it safe for home use?
Yes, it's IP30 rated and double insulated for safe use in residential and commercial installations.
Does it work with any thermostat?
Yes, it works with all ThermoSphere thermostats, using the thermostat's low-current signal to switch the higher-rated heating load.
Where should it be installed?
It's a surface-mount enclosure, typically fitted near the consumer unit or heating control circuit by a qualified electrician.
Who can install this product?
All electrical work should be carried out by a suitably qualified electrician in accordance with local safety regulations and standards.