I’m experimenting with replacing my mechanical TRVs with Sonoff TRVZB with external temperature sensors, using HA + Z2M and Versatile Thermostat. My boiler is Worcester Bosch Greenstar 30i with a fairly high minimum output - apparently, around 8kW.
My current setup is:
- Hive boiler receiver SLR1
- Hive wall-mounted thermostat in the living room with TRVs always fully open
- The thermostat runs on a schedule with several heating periods during the day and off at night
- Mechanical TRVs in other rooms, effectively limiting the temperature in those rooms.
- 2 always open bathroom towel rails and a small landing radiators serving as bypasses.
VT documentaiton recommends using TPI algorithm to have TRVs partially open, proportionally to the difference between current and setpoint temperatures. I like the idea, mainly because it reduces the noise of the TRVs doing full opening and closing runs (I’m not that much concerned about temperature fluctuations or boiler efficiency).
Now, my worry is that, with just a couple of radiators calling for heat with valves open to a fraction of the capacity, the risk of boiler short cycling increases. I’m aware that I have such risk anyway with the boiler with such a high minimum output. But partially open valves seem to increase it even further. I’m also aware about an opinion that the risks of short cycling are exaggerated anyway, given that boilers like mine have sufficient built-in protection and can switch off the burner and just keep the pump running.
Did anyone have experience with such setup with older boilers like mine? What do you think about it, should I be worried? Should I aim for a simple ON/OFF smart TRV regulation as a compromise?