Constant Circulation with TRVs. Is it explained as simply as, when the boiler is on, the circulator is moving hot water through the loops that feed radiators?
Not quite, but if you say, “When the structure requires heat, the circulator is moving heated water”, you’re awfully close. Unfortunately, though, the reality isn’t quite that simple. I’m referring ONLY to systems using TRVs or FHVs in the following (this may seem elementary, but first you have to understand how TRVs operate and what they can and cannot do). TRVs are two-way valves. Fluid goes in one side and it comes back out at any rate between “full on” and “full off.” In other words, a TRV is very simply a proportional flow valve. It’s the job of the TRV actuator to regulate the flow. The actuator senses temperature (usually room air) and has an adjustable scale. It regulates the degree of opening of the TRV valve body in an attempt to keep the actual room temperature just equal to the room temperature setting. If the sensor detects that the actual air temperature is dropping below the setting, the valve is opened somewhat; if it detects a rise above setpoint, the valve is closed s
