Service Manual for Dry Channel HDC3/HDC6 Units
6
RELAY BOX
Figure 4.
Relay Box
The Main Power On/Off Switch is located on
the lower right side of the Relay Box. This is a
lighted double pull single throw (DPST) switch
rated at 20 Amperes. The Relay Box houses a 24
Volt Step-Down Transformer and six Solid State
Relays (SSR).
CONTROL DISPLAY
Figure 5.
Control Display
The display provides a readout of actual
temperature, set point temperature and fault
conditions.
The control board inside the Control Display
maintains the temperature of all three channels.
Each channel has an A & B zone. The control board
monitors each zone’s temperature and activates a
relay to supply power to the heater for that zone.
When the ON/OFF button is pressed, the display
cycles through the temperature of each channel.
If a fault is detected, the fault code is displayed.
The displayed temperature will be the average of
the two zones associated with that channel.
MAIN FEATURES
Main Power
On/Off Switch
I
On/Off
Function Control
Button
Select
Buttons
DISPLAY
DISPLAY
HEAT ON
READY
