I agree. My mother's c/h system is old. She has a gas boiler with a thermostat, and radiators. No TRV's, no room thermostats. The system is controlled by a time switch and the stat on the boiler, which is set to 4 on a scale that goes up to 10. This keeps the house warm, but not excessively so. If she feels it is getting too hot, she switches the system off by over-riding the time switch. I very much doubt that a TRV set to max would close in those circumstances. She's had the system for many decades, and at her age (93) doesn't want it changed. Not the most efficient, but it suits her needs.