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For replacement parts call 1-800-377-2787
 ©2008 McQuay International     (800) 432-1342     www.mcquay.com  

LIA266 / Version A: 5-18-07

McQuay Training and Development

Now that you have made an investment in modern, efficient McQuay equipment, its care should be a high priority.

For training information on all McQuay HVAC products, please visit us at www.mcquay.com and click on training, or call 540-248-9646 and ask for the Training 

Department.

Warranty

All McQuay equipment is sold pursuant to its standard terms and conditions of sale, including Limited

Product Warranty. Consult your local McQuay Representative for warranty details. Refer to Form

933-43285Y. To find your local McQuay Representative, go to www.mcquay.com.

This document contains the most current product information as of this printing. For the most up-to-date product information, please go to

 www.

mcquay.com.

Summary of Contents for LIA266

Page 1: ...377 2787 2008 McQuay International www mcquay com 800 432 1342 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 Installation Operation Manual LIA266 Group WSHP Supercedes LIA204 4 Date May 2007 ...

Page 2: ...s Tools Required 2 To Remove Existing Thermostat 3 To Install Thermostat 3 Remote Sensor Installation Optional 5 Terminal Designator Descriptions 6 Wiring Diagrams 6 Configuration Mode 8 Testing the Thermostat 11 Mode of Operation 12 Operating Modes 13 Troubleshooting 14 Factory Default Settings 15 ...

Page 3: ... Parts Diagram R12 W1 Y1 W2 O S1 S2 668375401 Y2 ...

Page 4: ...ilding codes Use this thermostat only as described in this manual 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 5 C System configurations 2 stage heat 2 stage cool Timing Backlight Operation 13 seconds after mode change or button press Terminations C R W1 Y1 W2 Y2 G O S1 S2 Package Co...

Page 5: ...ve existing thermostat base from wall 6 Refer to the following section for instructions on how to install this thermostat To Install 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 IMPORTANT Thermostat installation must conform to local and natio...

Page 6: ...stat base with mounting holes and feed the control wires through wire opening 9 Use supplied screws to mount thermostat base to wall 10 Insert stripped labeled wires in matching wire terminals See Wiring Diagrams section of this manual Pages 6 7 CAUTION Be sure exposed portion of wires does not touch other wires 11 Tighten screws on terminal block Gently tug wire to be sure of proper connection Do...

Page 7: ...or wire in conduit with other wires Wire 1 should run between the S1 terminal on the thermostat and the S1 terminal on the remote sensor Wire 2 should run between the S2 terminal on the thermostat and the S2 terminal on the remote sensor Connect the shielding of the wire to the S2 terminal on the thermostat 5 Disable the main sensor R12 on the thermostat by cutting it from the circuit board Remote...

Page 8: ...e cool W2 2nd stage heat Y2 2nd stage cooling G Fan O Override C O G Y2 W2 Y1 W1 R ELECTRONIC THERMOSTAT W 2 G W 1 Y 1 F E L U A P V R C O McQUAY SINGLE CIRCUIT Mark IV Board Low Voltage Terminal Board Terminal Designator Descriptions Wiring Diagrams Override Optional ...

Page 9: ...Y DUAL CIRCUIT Mark IV Board Circuit 1 Low Voltage Terminal Board Mark IV Board Circuit 2 Low Voltage Terminal Board ELECTRONIC THERMOSTAT O Override Optional W 2 G W 1 Y 1 F E L U A P V R C O W 2 G W 1 Y 1 F E L U A P V R C O ...

Page 10: ...eover Electronic Thermostat is in OFF mode 3 Press the or button to change settings within each screen 4 Press the SW6 button to advance to the next screen Note The SW5 button will return you to the previous screen 5 To exit configuration mode slide the Mode switch to Heat or Cool 2 Heat Source Set to g Press the or button to set to g Press the SW6 button to advance to the next screen FILTER DIFF ...

Page 11: ...nd 2 F to 9 F 1 0 C to 4 5 C Set the minimum separation between heat setpoint and cool setpoint in Auto Changeover Mode Press the or button to set deadband Press the SW6 button to advance to the next screen FILTER DIFF ROOM SET REMOTE FILTER DIFF ROOM SET REMOTE 7 Staged Off Outputs Select whether the outputs for heating and cooling are staged off independently or are satisfied simultaneously 1 ou...

Page 12: ...brate displayed room temperature to match actual room temperature Note When not set to 0 ROOM will display Press the or button to select Press the SW6 button to advance to the next screen FILTER DIFF ROOM SET REMOTE 11 Maximum compressor cycles allowed per hour 2 6 as many as needed and 2 6 maximum cycles hour Press the or button to select Press the SW6 button to advance to the next screen 9 Maxim...

Page 13: ...re 2 degrees above the room temperature and the A C should turn off There may be a fan delay on your system Heat Test 1 Slide Mode switch to Heat mode 2 Adjust the set temperature so it is 5 degrees above the room temperature 3 Heat should come on within a few seconds Status indicator may come on 4 Adjust the set temperature so it is 2 degrees below the room temperature and the heat should turn of...

Page 14: ...e setting 7 Page 9 as the room temperature drops The thermostat has the following operating modes OFF Heat Cool and Auto In OFF mode the thermostat will not turn on heating or cooling devices In the Heat mode the thermostat controls the heating system In the Cool mode the thermostat controls the cooling system In the Auto mode the thermostat operates as an auto changeover thermostat It will turn o...

Page 15: ...mostat controls the cooling system Heat Mode In heat mode the thermostat controls the heating system Auto changeover Mode In this mode the thermostat will automatically change from heat mode to cool mode or vice versa Pressing the or button in Auto mode causes the thermostat to display the heat set temperature then the cool set temperature The set temperature that is displayed can be changed using...

Page 16: ...r fan continuously Room temperature is not correct Verify wall hole is plugged with putty or insulation calibrate thermostat see Configuration Mode Setting 10 Page 10 ROOM displays Room temperature offset is not zero see Configuration Mode Setting 10 Page 10 Status indicator Green light Cooling operation Red light Heating operating Status indicator option ON see Configuration Mode Setting 12 Page ...

Page 17: ...ay 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 1 8 LO 45 9 UP 90 10 Calibration 0 11 Maximum compressor cycles per hour 12 Lt 1 McQuay Auto changeover Electronic Thermostat Factory Default Settings ...

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Page 20: ... us at www mcquay com and click on training or call 540 248 9646 and ask for the Training Department Warranty All McQuay equipment is sold pursuant to its standard terms and conditions of sale including Limited Product Warranty Consult your local McQuay Representative for warranty details Refer to Form 933 43285Y To find your local McQuay Representative go to www mcquay com This document contains ...

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