HAMWORTHY HEATING LTD
56
Merley Boiler Sequence Controller
500001210/D
Quick setback
During quick setback, the heating circuit pump is deactivated and, in the case of mixing valve
circuits, the mixing valve is fully closed.
Function with room sensor:
When using the room sensor, the function keeps the heating switched off until the room
temperature has dropped to the level of the Reduced setpoint or the frost level.
When the room temperature has fallen to the Reduced level or the frost level, the heating
circuit pump will be activated and the mixing valve will be released.
Function without room sensor:
Quick setback switches the heating off for a certain period of time, depending on the outside
temperature and the building time constant.
Example
Duration of quick setback when Comfort setpoint minus Reduced setpoint = 2°C
(e.g. Comfort setpoint = 20°C and Reduced setpoint =18°C)
Outside
temperature
composite:
Building time constant:
0
2
5
10
15
20
50
15 °C
0
3.1
7.7
15.3
23
30.6
76.6
10 °C
0
1.3
3.3
6.7
10
13.4
33.5
5 °C
0
0.9
2.1
4.3
6.4
8.6
21.5
0 °C
0
0.6
1.6
3.2
4.7
6.3
15.8
-5 °C
0
0.5
1.3
2.5
3.8
5.0
12.5
-10 °C
0
0.4
1.0
2.1
3.1
4.1
10.3
-15 °C
0
0.4
0.9
1.8
2.6
3.5
8.8
-20 °C
0
0.3
0.8
1.5
2.3
3.1
7.7
Duration of quick setback in hours
Quick setback is possible with or without a room sensor
Line no.
Operating line
HC1
790
Optimum start control max
791
Optimum stop control max
Optimum start / stop control
Line no.
Operating line
HC1
780
Quick setback
Off
Down to reduced setpoint
Down to frost protection setpoint
Optimum start control max
Optimum stop control max
The change from one temperature level to the other is optimized in a way that the
Comfort setpoint is reached at the relevant switching time.
The change from one temperature level to the other is optimized in a way that the
Comfort setpoint minus 1/4 °C is reached at the relevant switching time