Central Heating With Analog Input Control Of Setpoint; Ch Mode 4 - Slant/Fin VGH-299-CH Installation And Service Manual

12.8.5 C H
ENTRAL EATING WITH ANALOG INPUT CONTROL OF SETPOINT
CH mode is set to 4. In this mode of operation, the boiler CH setpoint is controlled by an analog input signal
provided by a remote means such as a Building Management System or a system controller. The analog input 0-
10 Vdc is used to adjust the boiler setpoint between the CH_Setpoint_Min and the CH_Setpoint_Max settings.
The minimum analog input signal will correspond to the CH_Setpoint_Min parameter and the maximum analog
input signal will correspond to the CH setpoint maximum parameter. All other safety and control functions
associated with the boiler will react normally to adverse condition and override control of the analog signal to
prevent an upset condition. This means for example that when signal is going up faster than the boiler can regulate
that the boiler will slow down to prevent overshoot in temperature.
The CH_Setpoint_Min and CH_Setpoint_Max parameters can be adjusted to provide the desired temperature
adjustment band. A heat request will be generated by an input of 1.5 volts or higher. The setpoint modulation will
occur between 2 and 9 volts. The request for heat will be removed when the voltage drops below 1 volt.
Figure 12. 4
 RT input must be shorted to generate heat demand. / Min/Max CH power setting is limiting 0-10V range.
Parameters
CH_Mode
CH_Setpoint_Minimum
CH_Setpoint_Maximum
Table 12. 16
Level (Default) Value
2: Installer 0
2: Installer 68 ºF (20 ºC)
2: Installer 194 ºF (90 ºC)
E93.1601EN032.C VGH installation manual
; CH 4
MODE
Settable
Mode 0, 1, 2, 3, 4, 5
68...194 ºF (20...90 ºC)
68...194 ºF (20...90 ºC)
75