Support for all of your ESI Products


  • 6 Series WiFi compatibility

    Only the ESRTP6CW and ESRTP6WHW are WiFi compatible via the Centro app. If you have the ESRTP6C located on the wall within a new build property you will need to upgrade your thermostat to ESRTP6CW via your builder or installer. The WiFi connection advice is shown on the product technical detail section.

  • Locking & unlocking your RTP6C & RTP6CW programmable room thermostat 

     To lock your thermostat, press the menu button (three bars) and scroll through the settings to find screen lock. Select partial or full lock by pressing the arrows then round home button to confirm your setting. 

    To unlock your thermostat, press and hold the menu button (three bars) until the screen lock disappears. 

  • To remove UNBOIL message from ESi Series 4 thermostats (ESRTP4, ESRTP4+, ESRTP4RF, ESRTP4RF+)

    1. Move the slider bar to the OFF position.
    2. Hold the >> button and insert a pin or similar into the
      reset hole under the slider bar at the same time.
    3. Release the reset and >> button.
    4. Move the slider bar to AUTO.
    5. Press the HOME button.

    This should remove the unboil message from the screen, you may need to reset the time and date on your thermostat.

  • Why does my programmable room thermostat display flash between current time and another time with the letter h?

    If you would like to temporarily override the current temperature you can do this using the +/- buttons. The display will then alternate between the current temperature and the time left until the next on period where h stands for the number of hours left.

  • What is the wireless transmission distance?

    Up to 30m in open terrain

  • How many wireless room thermostats can communicate with one receiver?

    Your wireless receiver is designed to communicate with one room thermostat, unless the documentation of your product says otherwise.

  • How do I wire up the ESCTD Mechanical Dual Cylinder Thermostat?

    For the ESCTD, ensure the feed from the programmer is to C (Common) and Output/Call for Heat is to 1. These are the two outside terminals.

  • Electronic Cylinder Thermostat (ESCTDE/B) – How do I set the “boost” time?

    The boost can be set to occur at a time that suits the homeowner. For example, if set to 7 days – then the “boost” occurs exactly every 7 days. So if you switch off the power and back on again at noon on a Monday (for example) the boost will occur every Monday at Noon.

  • Electronic Cylinder Thermostat (ESCTDE/B) calling for heat all the time

    The ES-CTDE/B will call for heat when first connected to lift the Cylinder to 61°C and hold it there for one hour to eliminate any legionella bacteria that may be lying in the Cylinder. This is its first “anti-legionella” boost – thereafter, this process is repeated every week. After this initial hour the thermostat will be controlled by the Programmer and will hold the cylinder at whatever (lower) temperature the adjustable in-built thermostat is set at. Most Cylinders can be set around 48°C which is much more economical than holding at around 65°C and always having to add cold water whenever the hot is used.

    However, if your Boiler output temperature is too low, then the ESCTDE/B cannot get to 61°C so it just keeps trying. The solution is simply to turn up your Boiler Output temperature and this will enable the Cylinder to reach 61°C, after an hour at this temperature the unit will obey the Programmer and operate to the set point (for example 48°C.)

  • Electronic Cylinder Thermostat (ESCTDE/B) “Volt Free Contacts”?

    This product is not Volt Free and requires a permanent Live and Neutral, the Common terminal normally being supplied by the Programmer or Timeclock. The ESCTDE/B does not require a link unless being used in a system with no Programmer or Timeclock, in which case a link between the Live and Common is required.