w.Intercom = i;OpenTherm/Modulation of Nefit NXT HRC24 CW3 doesnt seem to work with Tado X wireless receiver. — tado° Community

OpenTherm/Modulation of Nefit NXT HRC24 CW3 doesnt seem to work with Tado X wireless receiver.

Jaap01
Jaap01 ✭
edited December 20 in General Questions & Topics

Hi,

I have a question regarding OpenTherm/modulation on my heating system. I am suspecting that it only works on Relay and not OpenTherm. I have installed everything according to the installation steps in the Tado app. I have made the following Observations:

  • When my Tado x heating devices require heat but only 1 out of 3 flames are showing, the heating symbol on the wireless receiver lights up. But it does not activate my Boiler. Only when I turn up the temperature and more heat is required my Boiler fires up.
  • When I press the heat boost button on the wireless receiver the relay led does light up green and the boiler starts working.
  • The OpenTherm LED on the wireless receiver never lights up.
  • Minimum pump % of the boiler is set to 30%. Lower is not possible.
  • All wires are installed on the correct position according to the app with the wireless receiver and the orange OpenTherm module on my Boiler.

I hope there is someone that is able to help me out because I have not been able to find anything on the internet.

If any additional information is required I will be glad to provide it.

Answers

  • tulloch
    tulloch ✭✭
    edited December 21

    I use Opentherm on a Baxi boiler and have observed the same. One "flame" can be lit nearly all day but the boiler is not firing all the time. The set temperature however is maintained very smoothly without the wild fluctuaions I would previously see on relay. I have also checked the "flow temperature optimisation" and the max flow temperature is being adjusted, currently 52 with 7 degrees outside, relay could not do this. At first i thought this was a fault but support checked the system and assured all is well. I have also noticed that the initial heating in the morning can overshoot a bit.

    This morning the boiler fired up to raise from 20.8 to 22, three flames. When it reached 22.2 it was down to one flame. Over the next 2 hours it dropped to 21.8 but one flame was on for all of that time. Then the temperature went up to 22.3 over the next hour and the one flame went off shortly after and is still off now.

    The Opentherm led on the receiver is not on.

  • Jaap01
    Jaap01 ✭
    edited December 21

    Hi Tulloch,

    Thanks for your reply, after some further investigation and your comment I had the idea to inspect the burner % and the pumpflow %. I noticed they would still be at 0% when my boiler was not fired up. however, when I turned up the temperature between the 2 and 3 ''flames'' I did notice both % fluctuating. This means they are modulating.

    I am suspecting at the 1 flame when only 1-2 degrees of temperature increase are needed the demand of the boiler is too low to activate it (pump cant go lower then 30%).

Categories