Cascading; System Setup; Boiler Cascade Communication Setup; Cascading System Setup - Slant/Fin VGH-299-CH Installation And Service Manual

15

CASCADING

System setup

NOTE: for proper functioning of the system, some settings have to be changed, see § 15.4.2 "Emergency mode".
The boiler controller can control multiple boilers in a cascade setup.
A system sensor input is available on the burner controller to measure the cascade system supply temperature.
A circulator output is also available to run the system circulator, as well as an output for the DHW circulator.
When the CH supply temperature is calculated based on an outdoor sensor, only one outdoor sensor is needed.
This sensor is connected to the managing boiler and calculates the CH setpoint for the cascade system.
A cascade system can be used with an DHW indirect tank. A DHW circulator and sensor can be connected to
the managing boiler.
Cascade boiler circulator connections for system configuration for handling DHW indirect tank or Central Heating
demand. All boilers handle either indirect tank or Central Heating demand at one time.
Figure 15. 1

Boiler cascade communication setup.

In order for the system to work for cascade the communication busses must be parallel linked together. The
managing boiler uses the AL-bus connection 20-21 for the cascade. The depending boilers must be connected to
the managing boiler on the 10-11 connection terminals.
It is important that the power on the 10-11 connection terminals on all dependent boilers is switched to the OFF
position.
All boilers in the cascade system must have a unique address selected (see also § 15.2.1).
Before commissioning a cascade installation, a number of parameters have to be changed.
These parameters can be programmed on the unit itself.
Figure 15. 2
Boiler Boiler Boiler
Circu- Circu- Circu-
lator lator lator
Changes in parameter may only be carried out by a
skilled commissioning/service engineer, who has had
specific training for setting up the VGH range boilers. He
WARNING
will be able to check whether the installation functions
correctly after the parameter change has been done.
Parameters for cascade operation are found in the Module
cascade settings menu, located in the Boiler settings
menu.
Parameters in the Boiler cascade settings menu may not
NOTICE
be used.
E93.1601EN032.C VGH installation manual
Heating system
System
Circulator
Boiler
Circu-
lator
DHW
Circulator
93