Greenheck PVF Installation And Operation Manual Download Page 29

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Indirect Gas-Fired Heat Modules

The controller has four buttons, one for “Function”, one
for “Enter” and two for “Up” and “Down”. During normal
operation, the screen will show the version number of
the program that is installed in the FX controller. The
version number typically consists of a letter followed by
two digits. Press Up or Down arrows to scroll through
main menu, press Enter for numeric reading.

Stand-alone Furnace Control

Units without microprocessor controls will have a
standalone furnace controller. In this case, all the logic
for controlling the furnace is contained within the FX
controller. On this type of controller, the LED status
indicator lights show the following:

When the controller is ﬁrst turned on, or after 10
seconds of inactivity by the user, the display will show
the main menu. The items in the main menu are:

Reference - FX Controller

The FX controller is a programmable electronic
controller that is used on the 4:1 electronically
modulated furnace and the 8:1 staged furnace. It is pre-
programmed at the factory and normally requires few
or no changes to the settings. It has a digital readout
consisting of three large digits and three smaller status
indicator lights at the top. The status indicator lights
show:

Controller Interface

Key Function Description

Function

Enter

Down

LED Status Indicators

If the FX controller detects a fault, it will go into alarm
condition and a message code will appear on the
screen. Message codes that may appear include:

Program Mode

Program Mode allows the user to view the Program
Menu and edit the factory default settings. To access
Program Mode and view the Setpoints Menu, press
and hold the Function button for three seconds. While
viewing the Setpoints Menu, press the Up or Down
buttons to scroll through the menu options. To view
the setting of the selected menu option, press the
Enter button. To edit the setting, press the Up or Down
buttons while viewing the setting. To save the new
setting and return to the Setpoints Menu, press the
Enter button. To return to the Setpoints Menu without
saving the change, wait 15 seconds. To exit Program
Mode from the Setpoints Menu, wait for 15 seconds.

Inlet Air Sensor (iAS) (optional)

The Inlet Air Sensor monitors the temperature of the
inlet air. If the inlet air is above the setpoint, the inlet air
sensor shuts off the furnace and continues to supply
the warm outside air. The inlet air sensor is preset to the
factory-recommended 65°F for 8 stage furnaces and
60°F for 4:1 turndown modulated furnaces.

Discharge Air Temperature (dtS)

The Discharge Air Temperature setting is the
temperature the unit will discharge. The Discharge
Air Temperature setting is preset to the factory-
recommended 70°F. The actual discharge air
temperature can be displayed by pressing the Up or
Down button from the default screen.

Outside Air Temperature (OAt)

To temporarily display the outside air temperature, press
the Up or Down buttons from the default screen to
change the display until “OAt” is displayed, then press
the Enter button.

WARNING

Changing the default settings will significantly affect
performance. Only change a setting after reading and
understanding this entire manual. Before changing
any settings, write down the factory-installed setting.

NOTE

The Enter button must be pressed to save any
changes made to the settings. If the Enter button
is not pressed, the unit will default back to the last
saved setting.

Display Text

Signiﬁcance

FXX

Default display

Discharge air temperature

oAt

Outdoor air temperature

Sot

Discharge air temperature setpoint by

Microprocessor input

rCt

Discharge air temperature by room