McQuay FCVC, Installation And Maintenance Manual

Page: 67 / 82

McQuay IM 846 Page 67
Operation
Operation
Thermostat Button Operation
The thermostat interface (Figure 4) contains buttons for use in
navigating to accompanying menus/screens and for performing
specific operations. These buttons and operations are described
below.
Figure 4: Thermostat interface (model #TA170-001 shown)
System Button Operation
The System button (Figure 4) contains and displays the
following modes of operation:
OFF —All thermostat outputs are off. The fan is still
operational if FAN ON is selected.
AUTO —The thermostat automatically selects heating or
cooling mode depending on the set point and room
temperature. If demand exists, the appropriate HEAT or COOL
icon illuminates. A 3°F dead band is provided to prevent short
cycling between heating and cooling modes. After changeover,
the control point automatically shifts so that the control OFF
point equals the set point temperature.
COOL —The thermostat operates as a cooling only
thermostat.
HEAT —The thermostat operates as a heating only thermostat.
UP/Down Arrow Button Operation
Use the Up and Down arrow buttons (Figure 4) to increase or
decrease the temperature.
Fan Button Operation
Use the Fan button (Figure 4) to control operation of the fan.
In the ON position, the fan output operates continuously. In the
AUTO position, the output cycles with demand. In the OFF
position, all outputs are off.
Note – Model #TB170-001 (part #107345336) has staged fan
control.
Speed Button Operation (TA170-001)
The fan Speed button (Figure 4) for model #TA170-001 (part
#107345335) is determined by manually selecting HI, MED,
or LO. Press and hold the Speed button for five seconds to
toggle the displayed temperature from Fahrenheit to Celsius.
F/C Button Operation (TB170-001)
Model #TB170-001 (part #107345336) is configured for
staged fan control and therefore utilizes a F/C button
(Figure 4) instead of a Speed button. When pressed, the F/C
button toggles between Fahrenheit and Celsius.
Verifying Thermostat Operation
To verify thermostat operation after mounting and wiring it,
perform the following:
1
Energize the system.
2
Set the fan to ON.
3
Select each fan speed, if available, to verify operation.
4
Set the system button to AUTO or other available selection.
5
Using the UP arrow, adjust the temperature to more than
5°F above ambient temperature to cycle on heating.
6
Using the DOWN arrow, adjust the temperature to more
than 5°F below ambient temperature to cycle on cooling.
OFF
HEAT
COOL
AUTO
FAN
BUTTON
SYSTEM
BUTTON SPEED
BUTTON
or
F/C
BUTTON
(part #107345336)
UP/DOWN
ARROW
BUTTONS
MODES: