Ch With An Outdoor Temperature Reset And Thermostat; Ch Mode 1 - Slant/Fin VGH-299-CH Installation And Service Manual

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.
P_CH_Max
Maximum boiler power for CH operation
P_CH_Min
Minimum boiler power for CH operation
12.8.2 CH
WITH AN OUTDOOR TEMPERATURE RESET AND THERMOSTAT
If the parameter CH_Mode 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.
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 § 12.7.1).
CH SETPOINT
°C °F
93 200
Design
82 180
Boiler
71 160
60 140
49 120
Boiler
Mild
Weather
38 100
27 80
16 60
Figure 12. 3
CH outdoor reset curve
The outdoor reset curve can be changed by adjusting the design and mild weather reference temperatures. The
calculated CH-setpoint
Reset_Curve_Boiler_Maximum.
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.
Shutdown temperature
When the outdoor temperature rises above Warm_Weather_Shutdown, the call for heat 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
Warm_Weather_Shutdown
Warm_Weather_Shutdown
72
Level Default Value
2: Installer 1
2: Installer 176 ºF (80 ºC)
2: Installer 120 sec.
2: Installer 180 sec
2: Installer 29 ºF (16 ºC)
2: Installer 100 %
2: Installer 1 %
20 40 60
-6 4
16
Outdoor Design
is always limited between
demand is stopped
plus 1.8 °F (1 °C).
minus 1.8 °F (1 °C) again, the demand will also start again.
E93.1601EN032.C VGH installation manual
Range
Mode 0-5
68.....194 ºF (20.....90 ºC)
10.....900 sec
10.....900 sec
0.....36 ºF (0.....20 ºC)
1.....100 %
1.....50 %
; CH
MODE
Boiler Maximum
Boiler Minimum
OFF
°F
100
80
°C
38
27
Warm Weather Shutdown
Outdoor Mild Weather
parameters Reset_Curve_Boiler_Minimum
when the outdoor temperature
When the outdoor
Table 12. 11
1
OUTDOOR TEMP.
has risen
temperature drops
and
above
below