Can I use a Shelly 1l with a 240v line thermostat

1. offizieller Beitrag

    Hi everyone,

    I currently have an old 2 wire thermostat controlling my hydronic heating boiler. Having measured the voltage at the thermostat it is 240v. Basically this thermostat acts as a relay when the desired temperate is obtained to open and close a switch. Unfortunately the thermostat is now old and the screen has stopped working so it needs replacing. However I want to replace it with a thermostat that I can control remotely and integrate into my smart home. Having done much research there aren't a lot of options for a 240v 2 wire line thermostat so I thought perhaps I could use a Shelly 1l.

    My idea is to basically put the Shelly relay in between the thermostat and the boiler - effectively a second relay. I would leave the thermostat set to on and then just use a schedule to turn on/off the Shelly relay. This will then use the thermostat to still regulate according to temperature.

    Attached is a photo of the current wiring on the thermostat. I am not quite sure how to calculate the wattage/amps for the circuit but have also attached a photo of the boiler which seems to indicate the amp are 0.8a max. I understand the Shelly 1l needs a min of 20w which would therefore be a really small rampage requirement for the circuit. I have also attached the spec of the existing Honeywell thermostat and the associate wiring diagram.

    Would someone be able to advise whether my thinking is valid and that this could work and also perhaps advise on how the Shelly 1L should be wired. Many thanks indeed.

    Existing thermostat wiring.jpeg

    Boiler specification.jpegThermostat wiring diagram.pngThermostat specification.png

    Einmal editiert, zuletzt von morgsman (30. Juli 2021 um 07:45)

    • Offizieller Beitrag

    Hi and welcome to the forum. :)

    Please upload your picture here in the forum.

    Thanks.

    The prefusing of the Thermostat switch loop should be max. 8A (not 0.8A).

    If you wore the Shelly contact in serie with the Thermostat, both Thermostat and Shelly must be on for the heater to operate , this would be the safest way, as long as the Thermostat works correct.

    Thanks. Yes you are right - the thermostat spec says up to 8amps. I am not quite sure what the actual amps output of the boiler is (the spec seemed to say 0.8a) - I would just want to make sure the Shelly 1L is getting 20w which I think is the minimum. At 240v I guess this would have to be about 0.08amps to provide 20w?

    I would love to check the right way to wire the Shelly 1L in this config if someone could advise? Thanks.

  • Dieses Thema enthält 2 weitere Beiträge, die nur für registrierte Benutzer sichtbar sind, bitte registrieren Sie sich oder melden Sie sich an um diese lesen zu können.