Salus 520 TX Thermostat Not Working

Discussion in 'Electricians' Talk' started by John-89, Jan 14, 2021.

  1. John-89

    John-89 New Member

    Hi

    We have been trying to fix an issue with our Salus 520 TX thermostat in that it only seems to communicate with our boiler in raising the temperature.

    It has been paired and has a solid red light on the receiver.

    Currently the thermostat is sitting in the hall reading 21 degrees. As an example if we set it to 30 degrees in manual mode the flame symbol appears on the thermostat, the green light flashes then turns solid on the receiver and the boiler (Valiant Ecotek 838) clicks on.

    When set for example to 10 degrees in manual mode, the green light goes off, the boiler clicks off but the temperature does not change and the same level of heat is passing through the radiators.

    This also applies to the scheduled periods including the final period 6 when set to 10 or even 5 degrees at 23:00, the radiators are still hot past this time and thermostat still reading 21 degrees.

    Our boiler engineer explained that there has to be enough of a difference with this system in the measured ambient temperature and the desired temperature for the boiler to fire on/off. But there seems to be an issue given when set to as low as 5 degrees the system is not cooling down.

    We have tried moving the thermostat next to the receiver in a much colder room, in the hallway, in the living room with tall ceiling all of which have no effect.

    Our house is Edwardian three story semi-detached.

    Any help hugely appreciated.

    John
     
  2. Mike83

    Mike83 Screwfix Select

    Has it always done this nor is it a new issue?
     
  3. jonathanc

    jonathanc Screwfix Select

    What do you mean boiler clicks off but same level of heat passes through the radiators? Is the boiler firing or not?
     
  4. John-89

    John-89 New Member

    Issue since new. Installed December 2020
     
  5. jonathanc

    jonathanc Screwfix Select

    get whoever installed it back to do it correctly then
     
  6. Mike83

    Mike83 Screwfix Select

    So the stat turns it on when requested.
    When you turn it off do the radiators ever cool down or does the heating stay on.
     
  7. John-89

    John-89 New Member

    As in when I'm testing it and setting the temperature to increase from what's on the thermostat I can hear an audible click and it gets louder, presumably firing and radiators would get hotter if allowed to continue. When setting a lower temperature than what's on the thermostat the boiler makes an audible click and becomes quieter, presumably stops firing. But when I check the radiators they are still the same temperature ie. not getting cooler as I'd imagine they would to achieve the requested lower temperature
     
  8. John-89

    John-89 New Member

    No radiators remain same constant temperature and heating stays on. Only way to reduce their output is through
    individual valves or adjusting flow temp on boiler
     
  9. Mike83

    Mike83 Screwfix Select

    If the stat doesn’t turn the heating off then it could be wired wrong.
     
  10. John-89

    John-89 New Member

    This is what I suspected - thanks
     
  11. jonathanc

    jonathanc Screwfix Select

    are you expecting your radiators to provide cooling when the temperature is set lower than room temperature?
     
  12. John-89

    John-89 New Member

    I'm expecting them to decrease in temperature or turn off entirely if the temperature is set low enough
     

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