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Adjustable Set Point Heating Parameters
Specific Parameters
CH_Mode
CH Setpoint
Sets the required supply temperature
CH_Post_Circulator_Time
Anti_Cycle_Period
Anti_Cycle_T_Diff
Aborts anti-cycle time when setpoint –
actual supply temp >Anti_Cycle_T_Diff.
Table 11.9
CH
WITH AN OUTDOOR TEMPERATURE RESET AND THERMOSTAT
This mode is available to both Heating Only (VGH-CH) and Combi (VGH-CO) boilers.
If the parameter CH_Mode (PB1) is set to 1, the "Outdoor temperature reset with room thermostat" mode is
selected.
This mode will only function when an outdoor temperature sensor is connected. If the outdoor sensor is connected,
the boiler automatically uses Reset_Curve_Boiler_Maximum PB24).
The setpoint is calculated depending on the outdoor temperature as indicated in the following graph and the boiler
will react on the room thermostat (as described in paragraph 11.8.1).
CH SETPOINT
°C °F
93 200
Design
82 180
Boiler
71 160
60 140
49 120
Boiler
Mild
38 100
Weather
27
80
16
60
Figure 11.9
CH outdoor reset curve
The outdoor reset curve can be changed by adjusting the design and mild weather reference temperatures. The
calculated CH-setpoint is always limited between parameters Reset_Curve_Boiler_Minimum (PB23) and
Reset_Curve_Boiler_Maximum (PB24).
The outdoor temperature used for the CH_Setpoint calculation is measured once a minute and averaged with the
previous measurement. This is to avoid commuting when the outside temperature changes rapidly. If an "open"
outdoor sensor is detected the CH_Setpoint will be equal to the Reset_Curve_Design_Boiler (PB19).
Shutdown temperature
If the outdoor temperature rises above Warm_Weather_Shutdown (PB25), the heat demand is blocked, and the
circulators are stopped. There is a fixed hysteresis of 1.8 °F (1 °C) around the Warm_Weather_Shutdown setting.
This means that the demand is stopped when the outdoor temperature has risen above Warm_Weather_Shutdown
plus 1.8 °F (plus 1 °C). When the outdoor temperature drops below Warm_Weather_Shutdown minus 1.8 °F
(minus 1 °C) again, the demand will also start again.
98
Display menu #
PB1
PB3
PB5
PB9
PB10
20
40
60
-6
4
16
Outdoor Design
E93.1901EN032 Installation and Service Manual SlantFin VGH-CH / CO
Level
Installer
Installer
Installer
Installer
Installer
; CH
MODE
Boiler Maximum
Boiler Minimum
OFF
100
°F
80
°C
38
27
Warm Weather Shutdown
Outdoor Mild Weather
Default Value
Range
1
Mode 0-5
185 ºF (80 ºC)
68.....194 ºF
(20.....90 ºC)
120 sec.
10.....900 sec
180 sec
10.....900 sec
29 ºF (16 ºC)
0.....36 ºF
(0.....20 ºC)
1
OUTDOOR TEMP.
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