Installation & Operation Manual LIA266 Group: WSHP Supercedes: LIA204-4 Date: May 2007 Auto-changeover Electronic Thermostat 2 Heat/2 Cool, Auto or Manual Changeover, Hardwired Part No. 668375401 ● ● ● ● ● ● ● ● Configurable Two Stage Heat / 2 Stage Cool Systems Backlit Display Field Temperature Calibration Status Indicator Light Relay Outputs (minimum voltage drop in thermostat) Night Set-Back Override Reset For replacement parts call 1-800-377-2787 ©2008 McQuay International • www.mcquay.
Table of Contents Parts Diagram..............................................................................................................................1 Specifications...............................................................................................................................2 Important Safety Information......................................................................................................2 Package Contents/Tools Required...............................................
Parts Diagram S1 668375401 S2 W1 Y1 W2 Y2 O R12
Specifications Electrical rating: • 24 VAC/VDC (18-30 VAC/VDC) • 4 amp maximum total load • 1 amp maximum per terminal Temperature control range: 45°F to 90°F (7°C to 32°C) Accuracy: ± 1°F (± 0.
To Remove Existing Thermostat ELECTRICAL SHOCK HAZARD – Turn off power at the main service panel by removing the fuse or switching the appropriate circuit breaker to the OFF position before removing the existing thermostat. 1. Turn off power to the heating and cooling system by removing the fuse or switching the appropriate circuit breaker off. 2. Remove cover of old thermostat. This should expose the wires. 3. Label the existing wires with the enclosed wire labels before removing wires. 4.
To Install Thermostat (continued) 2. To remove cover, insert and twist a coin or screwdriver in the slots on the sides of the thermostat. 3. Put thermostat base against the wall where you plan to mount it (Be sure wires will feed through the wire opening in the base of the thermostat). 4. Mark the placement of the mounting holes. 5. Set thermostat base and cover away from working area. 6. Using a 3/16” drill bit, drill holes in the places you have marked for mounting. 7.
Remote Sensor Installation (Optional) Requires McQuay Remote Sensor Part Number 667720401 1. Remove cover from remote sensor housing. 2. Select an appropriate location for mounting the remote sensor. 3. Mount remote sensor unit using hardware provided. 4. Install two strand shielded wire between remote sensor and thermostat. Shielded wire must be used. Do not run remote sensor wire in conduit with other wires.
Terminal Designator Descriptions -C +R W1 Y1 W2 Y2 G O – – – – – – – – 24 VAC/VDC common 24 VAC/VDC hot 1st stage heat 1st stage cool 2nd stage heat 2nd stage cooling Fan Override Wiring Diagrams McQUAY SINGLE CIRCUIT ELECTRONIC THERMOSTAT O W G W Y F E L U A P V + 2 1 1 R C Mark IV Board Low Voltage Terminal Board -C +R W1 Y1 W2 Y2 Override (Optional) G O
Mark IV Board Circuit 1 Low Voltage Terminal Board O W G W Y F E L U A P V + 2 1 1 R C Mark IV Board Circuit 2 Low Voltage Terminal Board O W G W Y F E L U A P V + 2 1 1 R C McQUAY DUAL CIRCUIT -C +R W1 Y1 W2 Y2 ELECTRONIC THERMOSTAT G O Override (Optional)
Configuration Mode The configuration mode is used to set the McQuay Auto-changeover Electronic Thermostat to match your heating/cooling system. To configure the McQuay Auto-changeover Electronic Thermostat, perform the following steps: 1. Remove the cover of the thermostat by gently pulling on one of the corners. 2. Simultaneously hold the SW5 and SW6 buttons in for 5 seconds while the McQuay Auto-changeover Electronic Thermostat is in OFF mode. 3. Press the or button to change settings within each screen.
4. 1st Stage Temperature Differential (1°F to 3°F) (0.5°C to 1.5°C) Set the number of degrees between your “setpoint” temperature and your “turn on” temperature. Press the or button to set differential value. Press the SW6 button to advance to the next screen. 5. 2nd Stage Temperature Differential (1°F to 6°F) (0.5°C to 3.0°C) Set the number of degrees between when stage 1 turns on and when stage 2 turns on. Press the or button to set differential value. Press the SW6 button to advance to the next screen.
9. Maximum Heat Setpoint (55°F to 90°F) (13°C to 32°C) Adjust to control the maximum Heat set temperature allowed. Press the or button to select. Press the SW6 button to advance to the next screen. SET ROOM DIFF FILTER REMOTE SET ROOM DIFF FILTER 10. Room temperature offset (+9°F to -9°F) (+4.5°C to -4.5°C) Adjust to calibrate displayed room temperature to match actual room temperature. Note: When not set to 0, ROOM will display Press the or button to select.
Testing the Thermostat Once the thermostat is installed, it should be thoroughly tested. 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. Cool Test 1. 2. 3. 4. Slide Mode switch to Cool mode. Adjust set temperature so it is 5 degrees below room temperature. Air conditioning should come on within a few seconds. Status indicator may come on.
Mode of Operation The McQuay Auto-changeover Electronic Thermostat is a two-stage heat, two-stage cool thermostat. The thermostat activates the first stage of heating when the room temperature is below the heat set temperature (by the differential temperature). The second stage of heating will be activated if the room temperature continues to drop. The heat outputs are staged off (configurable, setting 7, Page 9) as the room temperature increases.
Operating Modes These are the possible operating modes of the McQuay Auto-changeover Electronic Thermostat. Off Mode In off mode, the thermostat will not turn on the heating or cooling appliances. Note 1: The indoor fan can be activated in every mode by sliding the Auto/On fan switch to the On position. Note 2: Off mode is used to enter the configuration setup (by pressing SW5 and SW6 simultaneously for 5 seconds). Cool Mode In cool mode, the thermostat controls the cooling system.
Troubleshooting Symptom Remedy No display Check for 24 VAC/VDC at thermostat; display is blank when 24 VAC/VDC is not present System fan does not come on properly Verify wiring is correct Check configuration (see “Configuration Mode,” Setting 2, Page 8) See “Fan Test” (Page 11) Thermostat turns on and off too frequently Adjust temperature differential (see “Temperature Differential,” “Configuration Mode,” Settings 4 and 5, Page 9) Fan runs continuously Check fan On/Auto switch, ON position runs ind
McQuay Auto-changeover Electronic Thermostat Factory Default Settings Note: Following are the factory default settings for the McQuay 2811 thermostat: 1. Heat pump 0 2. HS gE g 3. FC F 4. Differential 01 1 5. Differential 02 2 6. db 4 7. Staged outputs 8. LO 45 9. UP 90 1 10. Calibration 11. Maximum compressor cycles per hour 0 - 12.
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