Greenheck Microprocessor Controller (474706 IOM) TAP v1.04 June 2011 (ERCH, ERH, APEX, VER, ERT) - Manual (Page 28)

28 DDC Controller for Tempered Air Products
Display is hard to read. Unit Controller Display: Hold
Prg Esc ESC and
Prg Esc
ENTER at the same time, while
pressing
Prg Esc
DOWN or
Prg Esc
UP to adjust display contrast.
Remote Display: Hold Prg Esc ALARM, Prg Esc PRG, and Prg Esc ESC at the same time, while
pressing
Prg Esc
DOWN or
Prg Esc
UP to adjust display contrast.
Remote display panel
displays “NO LINK” or
is blank. Hold
Prg Esc
DOWN,
Prg Esc
UP and
Prg Esc
ENTER for 4 seconds. Set the display address
to 32. The display requires a standard 24 AWG six conductor phone cable
connected to the unit controller.
Red alarm button is
flashing. Press the
Prg Esc ALARM button to review and clear unit alarms. Enter the DATA
LOGGER menu to view previous alarms.
Controller resets itself
or is not on. Check the supply voltage to the controller at terminals G-G0. The board requires
24VAC. Check the 24VAC transformer in the unit control center.
Menus are locked with
a password. The factory default Manufacturer Password = 1000.
The factory default Service Password = 1000.
Temperature sensor
failure. Check the analog input terminal block (labeled terminals B1, B2, B3, etc) for loose
wires. Disconnect temperature sensors to check sensor resistance.
Troubleshooting
NTC Temperature Sensor Chart
120
110
100
90
80
70
60
50
40
30
20
10
0
4 6 8 10 12 14 16 18 20 22 24 26 28
Temperatur
e (ºF)
Resistance (kΩ)
®