OTGW with on/off thermostat - no opentherm messages when 'on'

[pbrouwer]

Recently I have started experimenting with controlling my heatpump (techneco elga) at home using otgw. So far I have only used otgw to monitor its performance. One of the challenges is to reduce the relative modulation of the heatpump so the temperature in the heating pipes does not increase too fast.

So far I have had no success with controlling the modulation when using a modulating thermostat (Honeywell Touch modulation). Therefore I bought an old on/off thermostat (Honeywell round on/off) to test whether this would be different in a simpler setup. According to the otgw documentation when a simple 'on' signal is given by the thermostat otgw would ask the heatpump to start heating.

When connecting the on/off thermostat to the otgw all goes well when the thermostat sends an 'off' signal. However when the thermostat sends an 'on' signal the otgw monitor indicates thermostat was disconnected and afterwards only sends rubbish over the serial port.

Thermostat_disconnected.png (71.33 KiB) Viewed 686 times

Any idea what goes wrong here. A crucial setting that I missed? I double checked and tested the wiring.
Anyone managed to get otgw working with an on/off thermostat?

[hvxl]

Which version of the firmware are you using? I can somewhat reproduce this on firmware version 6.4 by creating contact chatter instead of having a solid contact. On firmware version 6.5 it no longer happens. So the first step is to upgrade to 6.5, if you're still running an older version of the firmware.