LUX PSM400SA Horizontal 24VAC Thermostat User Manual

1. Introduction and Overview

This manual provides comprehensive instructions for the installation, operation, and maintenance of the LUX PSM400SA Horizontal 24VAC Thermostat. This low-voltage thermostat is designed for heating and cooling systems, featuring a snap-action mechanism and an adjustable heat anticipator for precise temperature control. Please read this manual thoroughly before installation and operation to ensure proper function and safety.

Figure 1: Front view of the white LUX PSM400SA horizontal thermostat. The display shows temperature markings from 50 to 90 degrees Fahrenheit, and the system and fan switches are visible at the bottom.

2. Safety Information

• WARNING: Always disconnect power to the heating/cooling system at the main fuse or circuit breaker panel before installing, removing, or servicing the thermostat. Failure to do so may result in electrical shock or equipment damage.
• Installation should be performed by a qualified technician if you are unsure about electrical wiring procedures.
• Do not short thermostat terminals.
• Ensure all wiring connections are secure and comply with local electrical codes.

3. Package Contents

Verify that your package contains the following items:

• 1 x LUX PSM400SA Thermostat Unit
• 1 x Instruction Guide (this manual)

4. Features

The LUX PSM400SA Thermostat offers the following key features:

• Low Voltage Operation (24V AC)
• Horizontal Mounting Design
• System Switching: Heat-Cool-Off
• Fan Switching: Auto-On
• Control Range: 45°F to 90°F
• Snap Action Mechanism for reliable switching
• Adjustable Heat Anticipator for enhanced comfort
• 750mV Compatible
• Terminal Designations: G, Y, W, RH, RC
• Hardwired Power Method

5. Installation (Setup)

Follow these steps to install your new thermostat:

1. Power Disconnection: Turn off the power to your heating and cooling system at the main fuse or circuit breaker panel. This is a critical safety step.
2. Remove Old Thermostat: Carefully remove the cover of your old thermostat. Disconnect the wires one by one, noting the terminal designation for each wire (e.g., G, Y, W, R). It is recommended to label each wire with its corresponding terminal letter.
3. Mounting the New Thermostat Base: Secure the base of the LUX PSM400SA thermostat to the wall using the provided screws and anchors. Ensure it is level for aesthetic purposes.
4. Wiring: Refer to the 'Wiring' section below for detailed connection instructions.
5. Attach Thermostat Body: Once wiring is complete, carefully attach the thermostat body to its base.
6. Restore Power: Turn the power back on to your heating and cooling system at the main fuse or circuit breaker panel.

6. Wiring

Connect the wires from your HVAC system to the corresponding terminals on the LUX PSM400SA thermostat base. The terminal designations are as follows:

• G: Connects to the fan relay.
• Y: Connects to the compressor contactor (for cooling).
• W: Connects to the heat relay (for heating).
• RH: Connects to the 24VAC heating power supply.
• RC: Connects to the 24VAC cooling power supply.

Important Wiring Notes:

• If your system has separate wires for heating (RH) and cooling (RC), connect them to their respective terminals.
• If your system has only one 'R' wire (common for both heating and cooling), connect it to the RH terminal. In this case, ensure the jumper between RH and RC is in place (if provided, or create one if necessary) to provide power to both heating and cooling circuits.
• This thermostat is hardwired and does not require batteries.

7. Operation

Once installed and powered, operate your thermostat using the following controls:

• System Switch: This switch allows you to select the operating mode for your HVAC system.
  • HEAT: The thermostat will control your heating system to maintain the set temperature.
  • COOL: The thermostat will control your cooling system to maintain the set temperature.
  • OFF: The heating and cooling systems are turned off. The fan can still be operated manually if the fan switch is set to 'ON'.
• Fan Switch: This switch controls the operation of your system's fan.
  • AUTO: The fan will run only when the heating or cooling system is actively operating to reach the set temperature.
  • ON: The fan will run continuously, regardless of whether the heating or cooling system is active.
• Temperature Adjustment: Use the temperature dial or slider on the thermostat to set your desired room temperature. The thermostat will then work to maintain this temperature within its control range of 45°F to 90°F.

8. Maintenance

The LUX PSM400SA thermostat requires minimal maintenance to ensure optimal performance.

• Cleaning: To clean the thermostat, gently wipe the exterior with a soft, slightly damp cloth. Do not use abrasive cleaners, solvents, or chemical sprays, as these can damage the thermostat's finish or internal components.
• Battery Replacement: This model is hardwired and does not utilize batteries for operation. Therefore, no battery replacement is necessary.
• Airflow: Ensure that the thermostat is not obstructed by furniture, curtains, or other objects that could interfere with proper airflow and temperature sensing.

9. Troubleshooting

If you encounter issues with your thermostat, refer to the following common problems and solutions:

If these steps do not resolve the issue, please contact customer support or a qualified HVAC technician.

10. Specifications

11. Warranty and Support

For detailed warranty information, technical assistance, or to purchase replacement parts, please visit the official LUX website or contact their customer support directly. Keep your purchase receipt as proof of purchase for any warranty claims.

LUX Customer Support: Refer to the contact information provided with your product packaging or on the official LUX website.