"D" button Diagnostic Function
38
Applicable Model:
GU100 / 508(11,12,21,22)1100
Description:
Enhanced diagnostic functions are now available with the touch of a button. Simply press the “D” button on the front
control panel to access features such as: inlet and outlet temperatures, air temperature inside the chassis, fan motor
RPMs, error code history and more!
Diagnostic Content
Example
Explanation
Software Version for CPU A
SA 01
CPU A running version 1
Software Version for CPU B
SB 01
CPU B running version 1
E1 through E9
E2 13
Error 2 in history is code 13
Press the “D” button when the unit is in standby mode (burner off):
Diagnostic Content
Example
Explanation
Outlet Temperature – O
O 125
Outlet is 125°F
Heat Exchanger Temperature – H
H 135
Heat exchanger is 135°F
Inlet Temperature – I
I 65
Inlet is 65°F
Air Temperature – A
A 60
Air is 60°F
Fan Motor RPM – P
P5800
Fan is spinning at 5800 RPMs
Press the “D” button when the unit is firing (burner on):
To exit diagnostic mode, simply press the "D" button at any time to return to normal display mode. You can still
access the GPM flow rate data by simply pressing either the UP or DOWN button when the unit is in normal display
mode and the burner is on.
