Swegon Indoor Climate Systems 2005 - Air distribution products - Rev. 25 April, 2006
www.swegon.comVHCa
Controller for resetting diffusers
FUNCTION
VHC is used to reset diffusers intended for both cooling and heating with supply air, with the temperature difference between the supply air and room as the controlling parameter. VHC has an adjustable temperature range of 1-5 degrees for the change-over point when the supply air temperature increases.
QUICK FACTS
- Adapted for diffusers CKD, BOC and CVH
- Can also control a motorised damper with on/off function
- Adjustable change-over temperature 1-5°C
- Supplied complete with room and duct sensors
- Can control up to 10 diffusers
- Temperature sensor of PT1000 type
DESIGN
The controller VHC is an electronic controller that compares the room temperature with the supply air temperature and switches the diffuser between horizontal and vertical air pattern with increasing over temperature. The switching operation is performed according to the two position principle. There is a LED mounted on the circuit card, which comes on in heating case. The change-over point with an increasing temperature is adjustable between 1-5°C. VHC is supplied complete with duct and room temperature sensors. The controller is installed with a duct sensor on a shelf, which can be adapted to most duct sizes, circular as well as rectangular.
MATERIALS AND SURFACE TREATMENT
The electronics are enclosed in a ABS-plastic case. Assembly shelf is made of galvanized sheet steel. The duct temperature sensor is made of stainless steel.
INSTALLATION (See figure 1)
The VHC with duct temperature sensor is installed in the supply air duct a maximum of 1 m before the first diffuser to be controlled. The room sensor is installed on a wall, suitably between 1.5 to 2 m above the floor. The temperature sensor must not be exposed to direct sunlight or air flow directly from the supply air diffuser. It is important that the room temperature sensor is installed in a position that is representative for the temperature of the occupied zone.
MAINTENANCE
Dirty products are cleaned by dusting or wiping with a damp cloth.
ENVIRONMENT/STANDARDS
The environmental product declaration and CE declaration are available from our website.
CONNECTION
VHC is connected to a 24 AC power supply. Connection is made in accordance with the wiring diagram, figures 2 or 4.
Figure 1. Wiring VHC to air terminal BOC.
Key to figure 1
1 = Controller VHC with duct temperature sensor
2 = Room temperature sensor
3 = Junction box, not included in the delivery
4 = Fixed motor cord 0.4 m
Technical data
Ambient temperature: | |
Operation | 0 °C – +50 °C |
Storage | –40 °C – +70 °C |
Storage Relative humidity | max. 90% RH,
non condensing |
Enclosure: | |
Material | ABS/PC-plastic grey |
Protection class VHC | IP 54 |
Room sensor | IP 30 |
Sensor | Pt1000 |
Accuracy, sensor, 0 to + 35°C | ±0,3 °C |
Time constant | aprox. 7 min |
Voltage supply | 24 VAC ±10% |
Power consumption | 1,5 VA |
The power consumption of the diffuser’s damper motor should be added to the overall power consumption, normally between 3 to 4 VA | |
Key to the wiring diagram figures 2 and 3
X1 = Heating setting tto > troom
X2 = Cooling setting tto < troom
1 = VHC controller
2 = Duct temperature sensor (DT)
3 = Room temperature sensor (RT)
4 = Setting of change-over temperature
Figure 2. The wiring diagram illustrates the connection to a supply air diffuser with a Belimo´s damper motor, normally mounted on CVH and ALC.
Figure 3.The wiring diagram illustrates the connection to a supply air diffuser with a Swegon´s damper motor, normally mounted on BOC and CKD.
DIMENSIONS
Figure 5.VHC controller with duct temperature sensor.
Figure 6.Room temperature sensor.
ORDER KEY
Product designation
SPECIFICATION EXAMPLE
RC XX
Swegons controller for diffusers with change-over between heating / cooling with following functions:
- Temperature sensor of Pt1000 type
- Adjustable change-over temperature
Registered design. The company reserves the right to make design changes without prior notice.