McQuay FCVC, Installation And Maintenance Manual

Page: 56 / 82

Page 56 McQuay IM 1016-1
2 For wall installations, mount the thermostat on an inside
wall approximately 5 feet above the floor. The location
should provide circulation at average room temperature.
Avoid direct sunlight or sources of hot or cold air in the
room or wall.
3 Remove the cover. Mount thermostat base assembly to
the outlet box using the screws provided, tighten the
screws evenly but do not over tighten. Connect wires as
shown in the appropriate wiring diagram for your
thermostat style.
4 To use a remote sensor on units with local sensing
capability, remove jumper JP-1 to disable local sensing.
Failure to remove JP-1 will cause improper operation of
the thermostat.
5 Remove the LCD plastic protective film. Reinstall the
cover assembly. Install the cover locking screw provided
in the hole at the left side of the control enclosure to
complete the installation.
6 Checkout: After wiring and installation are complete,
energize the system and check the operation. Adjust the
thermostat as necessary to complete at least one cycle.
Be sure the thermostat and all other equipment are
functioning correctly.
Thermostat Operation
These thermostats are designed to control On-Off, N.O. and
N.C. valves, relays and three-wire floating valves. These units
may include a fan switch with one or more fan speed
selections.
Table 2: Main and Secondary Output Operation*
Note: * Operation determined by configuration. See Dip Switch
Configuration Table.
Mode Button Operation
OFF: All thermostat outputs are off, fan is still operational if
connected to manual fan speed switch.
AUTO: The thermostat automatically selects heating or
cooling mode depending on the set point and room
temperature. The appropriate HEAT or COOL indicator is
enabled in addition to AUTO. A 3°F dead-band is provided to
prevent short cycling between heating and cooling modes.
After change-over the control points automatically shift so that
the heating off-point or the cooling off-point equals the set
point temperature.
COOL: The thermostat operates as a cooling-only thermostat.
The heating outputs are disabled.
HEAT: The thermostat operates as a heating-only thermostat.
The cooling outputs are disabled.
If constructed without a mode button, the thermostat operates
in Auto mode, subject to configuration of the 2/4 pipe jumper
and pipe sensor input.
Fan Speed Switch Operation
Fan speed is determined by manual selection from fan switch
OFF to HIGH, MEDIUM and/ or LOW. In units with the
Cycling Fan Option (demand output), the Fan operation
(CYCLING vs. CONTINUOUS) is determined by application
connections. In OFF position all outputs are off and display
blank.
Up/ Down Arrow Operation
A first touch of either arrow will display the set point (a single
set point is employed for both heating and cooling). Continued
pressure on either arrow will scroll the set point to new values.
After three seconds with no pressure on either arrow, the
selected set point becomes effective and the display of the
room temperature resumes.
Setback Operation
Connection of the Setback Input to 24 VAC 1 will force the
control into unoccupied mode (see wiring diagram). Pressing
an arrow key or the mode button on the thermostat cover will
disable the setback input for one hour.
Pipe Sensor Operation
If cold water is detected, the system will operate in summer
mode and the Main output will be cooling. If hot water is
detected, the system will operate in winter mode, the Main
output will be heating and First Stage Secondary Output will
be disabled. In the case of an ambiguous reading, neither hot
nor cold, the thermostat will initiate a purge cycle.
Three Wire Floating Valve Operation
Open and Close outputs are used to position the valve. Stroke
time is factory set at two minutes. Outputs are off after
reaching full on or off position. Valves are periodically reset
for accuracy.
Outside Air Damper Operation
This output is ON any time the control is turned ON.
Output
3-Wire
Floating
Off with
Demand
On with
Demand
Main 1
Terminal 10
Powers main
valve open
On at temp
demand
On at temp
demand
Main 2
(Terminal 12)
Powers main
valve closed
Cycles on with
demand
Cycles on with
demand
Secondary
(Terminal 11)
Powers
secondary
valve open
Summer: Off with
heat demand
Winter: Disabled
Summer: On with
heat demand
Winter: Disabled
Secondary 2
(Terminal 13)
Powers
secondary
valve closed
On at second
stage heating
demand
On at second
stage heating
demand