ᐅ ERR activates actuator despite being too warm

Created on: 19 Feb 2021 08:16
M
Malz1902
Hello everyone, and please don’t be too harsh.
Actually, the electric heating resistors (ERRs) have been removed from all rooms except the children’s room.
The thermostat is a rotary type (RTR) from Halmburger, with a scale from 0 to 6.
According to the manual, setting it to level 4 should maintain a temperature of around 20°C (68°F), but in the room it is currently 22°C (72°F), and the actuator is open, so the room is being heated. If I set the room thermostat to level 3, you hear a click and the actuator closes, but shortly after it opens again, even though the room temperature remains just under 22°C (72°F) and the RTR is still set to level 3.

Shouldn’t the RTR only open the actuator again once the temperature in the room drops below, I think, 16°C (61°F) at setting 3 on the RTR?

Or am I making a mistake in my thinking? The temperature is measured directly next to the RTR.

Shouldn’t the RTR cut power to the actuator when the room temperature reaches a certain value? I understand that these analog RTRs aren’t very precise, but a deviation of 6–7°C (11–13°F) seems quite large to me.
M
Malz1902
19 Feb 2021 09:03
±0.3° is okay.
The setting on the control unit corresponds roughly to 5°C (9°F) increments (so: 1 = 5°C / 2 = 10°C / ... up to 6 = 30°C).
For example, at level 3 it should be around 15°C (59°F), but the room temperature is 22°C (72°F), which is a 7°C (13°F) difference. The rotary thermostats aren’t that inaccurate, are they?
tomtom7919 Feb 2021 09:07
Turn the dial until the temperature is right, then remove the dial knob and place it back in the correct position. 🙂
A
Alessandro
19 Feb 2021 09:12
These cheap bimetallic controllers are just rough estimates. Buy something reliable with a digital display. The wall temperature should not affect the controller unless it has cooled down.
Mycraft19 Feb 2021 09:52
Malz1902 schrieb:

The scale on the control unit corresponds roughly to 5°C (9°F) increments (i.e., 1: 5°C (9°F) / 2: 10°C (18°F) ... up to 6: 30°C (54°F)).
So, at level 3, it should be about 15°C (59°F), but the room temperature is 22°C (72°F).

One of the biggest misunderstandings with these devices is that the scale is linear.