DENSO CORPORATION CLASSIC PLUS 26 - Manual (Page 23)

ELECTRICAL SYSTEM
15
1. Basic Operation of Classic Plus 26 Electrical Circuit
There are two basic components used to control the operation of the Classic Plus 26 Electrical System:
• Control Panel Assembly
• Control Box
The Control Panel Assembly contains the Control Panel, Control Board (with inputs for the freeze and
room temperature thermistors), drain switch, and a microprocessor.
A. Fan “Only” Mode
Low Fan Mode - When the “Low” Fan Mode button on the control panel is pressed, the microprocessor
turns on the button’s LED and activates the Fan “On” Relay (Relay Board), sending line voltage (208/230
VAC) to the N.C. (Normally Closed) contacts of the fan “mode” relay. This output is connected to the J5
terminal (relay board) where the LOW SPEED wire of the fan motor is connected.
High Fan Mode – When the “High” Fan Mode button on the control panel is pressed, the microprocessor
turns on the button’s LED and activates both the Fan “On” Relay and Fan “Mode” Relay. This sends line
voltage (208/230 VAC) from the Fan “On” Relay to the N.O. (Normally Open) contacts of the Fan “Mode”
Relay. This output is connected to the J6 terminal (Relay Board) where the HIGH SPEED wire of the Fan
Motor is connected.
B. Cool Mode - In Addition to Fan “Only” Mode (as described above)
When the Cool On/Off button on the control panel is pressed, the microprocessor turns on the button’s
LED and if the Temperature Set Point is less than the current room temperature, activates the Compres-
sor Relay (Relay Board). This sends line voltage (208/230 VAC) to the J4 terminal (Relay Board) where the
wire from the Compressor wire harness is connected.