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Wiring Diagram
Configuration Mode
The configuration mode is used to set the McQuay 668811101 thermostat to match your heating/cooling system.
The McQuay 668811101 thermostat functions with heat pump, air conditioning, gas, oil or electric heat systems.
1. To enter the configuration mode, simultaneously hold down the and buttons while
the McQuay 668811101 thermostat is in OFF mode.
2. Press the or button to change settings within each screen.
3. Press the
PROG button to advance to the next screen.
Note: The MODE button will return you to the previous screen.
4. To exit configuration mode, hold the
PROG button for 6 seconds.
2. Differential (1°F - 5°F) (1°C - 3°C) – Set the number of degrees between your “turn on”
temperature and your “setpoint” temperature.
Press the or button to set differential value.
Press the
PROG button to advance to the next screen.
3. Deadband (1°F - 9°F) (1°C - 5°C) – Set the minimum number of degrees between
your heating system activation and your cooling system activation.
Press the or button to set deadband value.
Press the
PROG button to advance to the next screen
1. Temperature scale (F or C) – Choose Fahrenheit or Celsius.
Press the or button to select.
Press the
PROG button to advance to the next screen.
Configuration Mode Settings
4. Heat pump – Press the or button to configure as heat pump, or non-heat pump
system.
• ON = Heat pump system – 4 minute time delay with heat and cool
• OFF = Non-heat pump system – 4 minute time delay with cool only
Press the
PROG button to advance to the next screen
5. Lockout (0-8°, NITE, COOL-HEAT) – Select the number of degrees set temperature
can be changed during keypad lockout or select to lockout during NITE period only.
COOL-HEAT lockout allows adjustment of the set temperatures to the maximum heat set
temperature selected in Step 6 and minimum cool set temperature selected in Step 7.
Note: The mode cannot be changed when the thermostat is locked.
Press the or button to select.
Press the
PROG button to advance to the next screen
6. Maximum Heat Setpoint (45°F - 90°F) (7°C - 32°C)
Adjust to control the maximum heat set temperature allowed.
Press the or button to select.
Press the
PROG button to advance to the next screen
7. Minimum Cool Setpoint (45°F - 90°F) (7°C - 32°C)
Adjust to control the minimum cool set temperature allowed.
Press the or button to select.
Press the
PROG button to advance to the next screen
ON
Starting the Thermostat
8. Room temperature offset (+9°F to - 9°F) (+5°C to -5°C).
Adjust to calibrate displayed room temperature to match actual room temperature.
Press the
PROG button to advance to the next screen.
9. Maximum compressor cycles allowed per hour (d, 2-6).
– – = as many as needed, 2-6 = maximum cycles/hour
Press the
PROG button to advance to the next screen.
10. Status indicator light (ON, OFF).
Press the or button to select.
To exit configuration mode, press the
PROG button for 6 seconds.
Note: First button press activates backlight only.
1. Move the Fan Auto/On switch to the Auto position.
2. Press the
MODE button to enter desired operating mode.
3. Press
PROG to select program or non-program option.
Testing the Thermostat
Once the thermostat is installed, it should be thoroughly tested.
Cool Test
1. Press mode button until cool mode is displayed.
2. Adjust set temperature so it is 5 degrees below room temperature.
3. Air conditioning should come on. Green LED turns ON.
4. Adjust the set temperature 2 degrees above the room temperature and the A/C should
turn off. There may be a fan delay on your system.
Note: There is a four-minute time delay to protect the compressor after it turns off.
Heat Test
1. Press mode button until heat mode is displayed.
2. Adjust the set temperature so it is 5 degrees above the room temperature.
3. Heat should come on. Red LED turns ON.
4. Adjust the set temperature 2 degrees below the room temperature and the heat
should turn off. There may be a fan delay on your system.
Note: For heat pumps, there is a four-minute delay to protect your compressor.
Fan Test
1. Slide fan switch to ON position.
Indoor fan turns ON.
2. Slide fan switch to Auto position.
Indoor fan turns OFF.
Mode of Operation
The McQuay 668811101 thermostat is a programmable, auto changeover, single stage heat, single stage cool
thermostat. It functions with air conditioning, heat pumps, gas, oil or electric heat systems.
The thermostat activates the heating appliance when the room temperature is below the set heat temperature
(by the differential temperature) and the red indicator light on the thermostat will light. The McQuay 668811101
thermostat will stop outputting and the red light will turn off when the call for heat has been satisfied. With heat
pumps, the thermostat will not let the compressor come on for 4 minutes after it turns off. This protects your
compressor.
When the room temperature is greater than the set cool temperature (by the differential temperature), the cooling
device is activated and the green indicator light on the thermostat will turn on. The McQuay 668811101 thermostat
will stop outputting and the green light will turn off when the call for cooling is satisfied. The thermostat will not let the
compressor come on for 4 minutes after it turns off. This protects your compressor.
The McQuay 668811101 thermostat has five possible operating modes: OFF, Heat, Cool, Heat & Cool and Program
mode. In off mode, the thermostat will not turn on heating or cooling devices. The manual fan can be turned on in
all operating modes using the fan switch and the fan speed can be set in all operating modes using the fan speed
switch. In heat mode, the thermostat controls the heating system. In the Cool mode, the thermostat controls the
cooling system. In heat & cool mode, the thermostat controls both the heating and cooling systems. In program
mode, the thermostat will automatically be controlled by the set program. Program mode can function with heat
mode, cool mode or heat & cool mode. The clock display alternates with the set temperature display for heat & cool
mode.
The program schedule can be overridden by changing the set temperature ( or button). This puts the McQuay
668811101 thermostat thermostat into a 2 hour temporary hold. After 2 hours, it will automatically return to the
program schedule.
The McQuay 668811101 thermostat also has a button lockout feature. This enables the thermostat to be set to the
proper mode and temperature and locked so it cannot be tampered with.
Setting the Time and Day of the Week
The time and day of the week must be set for your program schedule to operate correctly.
1. Press the
MODE button until you are in the OFF mode.
2. Press the
PROG button in for 6 seconds. Time displays.
3. Press the or button to adjust the time.
4. Press the
PROG button while the time is displayed. The display shows the day
currently set on the thermostat (1=Monday, 2=Tuesday, etc).
5. Press the or button to set the correct day of the week that today is.
Note: Press the PROG button in for 5 seconds to lock values into memory
and return to the OFF mode or press the
PROG button once to
enter programming.
• Set time is displayed
8. Press the or button to change set time.
9. Press the
PROG button to advance to the next screen.
Note: Transitions required after 11:59 PM must be programmed in the next day’s
MORN transition.
• Heat temperature is displayed (45°F to 90°F)
10. Press the or button to adjust heat set temperature.
11. Press the
PROG button to advance to the next screen.
• Cool temperature is displayed (45°F to 90°F)
Note: Cool cannot be set lower than heat temperature.
12. Press the or button to adjust cool set temperature.
13. Press the
PROG button to advance to the next screen.
Repeat steps 1-13 to program each day of the week individually or use the Simpleset
®
feature (see Page 14) to program every day the same as Monday.
When programming is complete, press and hold the
PROG button in for 5 seconds to return to the OFF mode.
PROG must display on the screen for the thermostat to follow the program schedule. If PROG does not appear,
press the PROG button until PROG displays.
Programming
Program Overview
The McQuay 668811101 thermostat programmable thermostat has four periods (MORN, DAY, EVE, NITE) that are
customizable for each day of the week. Each period will have a start time, heat temperature, and cool temperature.
The McQuay 668811101 thermostat monitors the day and time, while maintaining the specific conditions you have
chosen for each period in your program.
1. Press the
MODE button until you are in the OFF mode.
2. Press the
PROG button for 6 seconds.
3. Press the
PROG button twice.
• Day is displayed (1-7)
4. Press the or button to change the day you want to program
(1=Monday, 2=Tuesday, etc.).
5. Press the
PROG button to advance to the next screen.
Note: You can always press the MODE button to return to the
previous parameter.
• Period is displayed (MORN, DAY, EVE, NITE)
6. Press the or button to change period of day.
7. Press the
PROG button to advance to the next screen.
6-Wire,
MORN
DAY
EVE
NITE
HEAT
HEAT
HEAT
HEAT
COOL
COOL
COOL
COOL
MONDAY
1
MORN
DAY
EVE
NITE
HEAT
HEAT
HEAT
HEAT
COOL
COOL
COOL
COOL
TUESDAY
2
MORN
DAY
EVE
NITE
HEAT
HEAT
HEAT
HEAT
COOL
COOL
COOL
COOL
WEDNESDAY
3
MORN
6:00 AM
DAY
8:00 AM
EVE
6:00 PM
NITE
10:00 PM
HEAT
70°F
HEAT
62°F
HEAT
70°F
HEAT
62°F
COOL
78°F
COOL
85°F
COOL
78°F
COOL
82°F
MONDAY
thru
SUNDAY
Personal Program Schedule
Factory Preprogramming
The McQuay 668811101 thermostat comes preprogrammed with the following schedule:
Use the following personal program schedule to record your settings:
Simpleset® Programming
Lockout Function
After the complete Monday schedule is set (see Programming on Page 12), you are at the Day 2 screen:
1. Press the button once. Day 1 screen displays.
2. Press and hold the button for 3 seconds.
• The days of the week will count down from 7 to 1 and this will lock the
settings into memory.
• Once the schedule is locked in, you can go through each day and make
any changes you require. This feature speeds up the programming of
the standard weekday/weekend schedule.
3. Press and hold the
PROG button for 5 seconds to exit program mode and return to the OFF mode.
The McQuay 668811101 thermostat thermostat has a button lockout feature so the settings cannot be
changed or tampered with. With the lockout activated, any button press will result in “LOC” being displayed.
To activate the LOC function:
1. Press the
MODE button and hold it in.
2. Also press the
PROG button and keep both depressed for 10 seconds.
3. LOC will display and all buttons will be disabled.
To deactivate the LOC feature, repeat steps 1 & 2 above.
Simpleset
®
programming is a convenient method of programming the thermostat. Once the entire Monday (Day 1)
schedule is set, Simpleset
®
programming will copy the Monday schedule to every day of the week.
Operating Modes
There are six possible operating modes for the McQuay 668811101 thermostat. Off, Cool, Heat, and Cool & Heat
modes are accessed by pressing the Mode button. Program mode is accessed by pressing the Prog button. Continuous
fan mode is accessed by setting the auto/on switch to ON.
Cool and Heat Mode (Auto Changeover)
– In this mode, the thermostat controls
the cooling and heating systems, automatically changing over from one to the other as
needed.
Program Mode
– In this mode, the program function is on (PROG displays), and the
thermostat will automatically be controlled by the set program schedule. Program mode can
function with heat mode, cool mode or heat & cool mode. The program schedule can be
overridden by changing the set temperature ( or button). After 2 hours, the program
schedule will automatically be resumed. To manually return to the program schedule, press
the
PROG button twice.
Cool Mode
• In this mode, the thermostat controls the cooling system
Note: There is a four minute delay for your compressor to restart after it has turned off.
Heat Mode
• In this mode, the thermostat controls the heating system
Note: For heat pumps, there is a four minute delay for your compressor to restart after
it has turned off.
OFF Mode
• In this mode, the thermostat will not turn on the heat pump.
Continuous Fan Mode
• The indoor fan can be turned on manually in every operating mode by sliding the auto/on switch to ON.
CAUTION
Do not energize the air conditioning system when the outdoor temperature is below 50 degrees.
It can result in equipment damage or personal injury.
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