vindaalex
commented
6 months ago Unfortunately changes to the pwm routine in the thermostat are not that easy to implement. But I think you might still be able to get it working as used currently.
Working principle:
- The master schedules a switch to on and back off. This interval can be chosen, for a heat pump long intervals are preferred, 30 min pwm interval might be good start point.
- The relay includes the auto-off (maybe with even shorter auto-off time, slightly longer than the automation interval).
- An automation running each few (5?) minutes and checking the master thermostat state (heating or cooling) and as action switch relay 'on' again.
Would this allow you to keep the auto-off time?
Scenarios:
- When HA and the thermostat are working well it will schedule the on and off to your relay and the failsafe on the relay will not be triggered.
- The thermostat schedules on-off and after 'on' HA crashes: the relay will switch off due to the auto-off as the automation has not updated the relay either.
- The thermostat schedules on-off and after 'on' the master thermostat freezes: the automation will keep sending 'on' to the relay. I wonder if this a realistic scenario. In any case if a satellite would freeze in your current config it will give the same problem, i think?
stomko11
I have been using your thermostat for last 2 winters and it has been working quite well for me. Back in the days, I tried using master thermostat too, but it wasn't ideal. For zones, I am using on/off valves that take 2-5 minutes to open/close. I found out that master was not really in sync with zone valves. As a result, master would turn on when all of the zones were closed, etc., so I stopped using master and use simple automation to check every 5 minutes if there is need for heat from any of the zones, and if yes, turn on heater.
Now it looks like master thermostat has evolved and I am tempted to try that. However there is a thing that i am not sure how to approach - and that is failsafe mechanism.
To signal my heat pump, I am using dry relay. On that relay directly, I configured auto-off feature (15 minutes) as a failsafe. Means my automation runs every 5 minutes, and if there is need for heat, it sends switch.turn_on to relay regardless if it is on. As a result, relay receives that "on" signal and does not turn off for at least another 15 minutes (or if turned off intentionally sooner). If something would fail on HA end, relay would turn off after 15 minutes. Since master is sending ON only when there is need for heat, and OFF when there is not anymore, my failsafe would not be working anymore. I assume it would turn off.
Idea: Instead of just turning on/off, maybe there could be configurable parameter for master - to force sending on (or even off) in configurable interval. That would ensure that ON signal is sent constantly every X minutes. If something would happen on HA side, heating would turn off on its own latest in 15 minutes.