1. Introduction
This manual provides detailed instructions for the installation, operation, and maintenance of the PROTACTOR Electric Furnace Sequencer, model PT-S20KW. This sequencer is designed as a universal replacement for various electric furnace models, particularly those utilizing four heating elements. It manages the sequential activation and deactivation of heating elements and the furnace blower for efficient operation.
2. Safety Information
WARNING: Electrical shock hazard. Disconnect all power to the furnace before installing or servicing this component. Failure to do so may result in serious injury or death. Installation should only be performed by a qualified technician.
- Always ensure the main power supply to the furnace is turned off at the circuit breaker before beginning any work.
- Verify that the replacement sequencer matches the specifications of the original part.
- Wear appropriate personal protective equipment, including insulated gloves and safety glasses.
- Ensure all wiring connections are secure and correctly terminated to prevent electrical hazards and ensure proper operation.
3. Product Features
- Universal replacement for many electric furnace models.
- Features four switches to control heating elements and the furnace fan.
- Designed for electric furnaces with four elements, commonly used in 20 KW furnaces.
- Equipped with 1/4" quick connect terminals, clearly marked M1-M2, M3-M4, M5-M6, and M7-M8.
- Low voltage terminals include jumper bars that can be removed if specific wiring configurations require it.
4. Setup and Installation
Before proceeding, ensure all power to the furnace is disconnected. Refer to the furnace manufacturer's wiring diagram for specific connection details.
4.1 Identifying Terminals
The sequencer features clearly labeled quick-connect terminals:
- M1 and M2: These terminals control the first stage of heating elements and the blower fan. They are designed to activate first and deactivate last, ensuring the blower continues to run until the elements cool down.
- M3-M4, M5-M6, M7-M8: These terminals control additional heating elements, activating in sequence after M1 and M2, as dictated by the thermostat's demand.
- Bottom Terminals: These are for the 24-volt control circuit connections from the thermostat.
Figure 1: Top view of the sequencer, illustrating the quick-connect terminals M1 through M8.
4.2 Mounting the Sequencer
The sequencer is designed for socket mounting. Secure it firmly in the designated location within the furnace control panel. Ensure proper orientation as per the furnace's original design.
Figure 2: Rear view of the sequencer, showing the mounting plate for secure installation.
4.3 Wiring Connections
- Before disconnecting the old sequencer, take a photograph or make a detailed drawing of all existing wire connections.
- Carefully remove wires from the old sequencer, noting which wire connects to which terminal.
- Connect the 24-volt control circuit wires to the bottom terminals of the new sequencer.
- Connect the heating element and blower fan wires to their corresponding M-terminals (M1-M2, M3-M4, M5-M6, M7-M8) on the new sequencer. Ensure all quick-connect terminals are fully seated.
- If the furnace wiring requires separate low-voltage connections, the jumper bars on the low voltage terminals may be carefully removed using wire cutters. Consult the furnace wiring diagram to determine if this is necessary.
Figure 3: Side view of the sequencer, highlighting the stacked design and multiple terminal connections.
After all connections are made, double-check them against your notes and the furnace wiring diagram. Restore power to the furnace only after confirming all connections are correct and secure.
5. Operating Instructions
The PROTACTOR Electric Furnace Sequencer operates automatically in response to the thermostat's call for heat.
- When the thermostat calls for heat, the 24-volt control circuit energizes the sequencer.
- The M1 and M2 terminals will close first, activating the initial heating elements and the furnace blower. This ensures air circulation begins before full heat is generated.
- If more heat is required, subsequent stages (M3-M4, M5-M6, M7-M8) will close in a timed sequence, bringing additional heating elements online.
- When the thermostat satisfies the heat demand, the heating elements will deactivate in reverse sequence.
- The M1 and M2 terminals, controlling the blower, will remain closed for a short period after the last heating element deactivates. This "fan off delay" allows the blower to continue running, dissipating residual heat from the elements and preventing overheating.
No user interaction is required for the sequencer's operation once correctly installed.
6. Maintenance
The PROTACTOR Electric Furnace Sequencer is designed for reliable, maintenance-free operation. However, periodic inspection is recommended as part of general furnace maintenance.
- Annual Inspection: During routine furnace servicing, a qualified technician should inspect the sequencer for any signs of wear, discoloration, or loose connections.
- Cleanliness: Ensure the area around the sequencer is free from dust and debris, which can impede proper heat dissipation.
- Connection Integrity: Verify that all quick-connect terminals remain securely attached to their respective wires.
Do not attempt to disassemble or repair the sequencer. If a malfunction is suspected, replace the unit.
7. Troubleshooting
If your electric furnace is not operating correctly, the sequencer may be a contributing factor. Always ensure power is disconnected before inspecting components.
| Problem | Possible Cause | Solution |
|---|---|---|
| Furnace fan runs continuously, even when no heat is called for. | Sequencer contacts (M1/M2) stuck in closed position. | Replace the sequencer. |
| One or more heating elements do not activate. | Corresponding sequencer contacts (e.g., M3/M4) are faulty or open. | Test individual elements and sequencer stages. Replace sequencer if faulty. |
| Furnace does not heat at all. | No 24V control signal to sequencer, or sequencer completely failed. | Check thermostat and 24V transformer. If 24V is present at sequencer, replace sequencer. |
| Blower fan does not turn on. | Sequencer contacts (M1/M2) not closing, or fan motor issue. | Verify fan motor operation. If motor is functional, replace sequencer. |
If troubleshooting steps do not resolve the issue, contact a qualified HVAC technician.
8. Specifications
| Feature | Detail |
|---|---|
| Brand | PROTACTOR |
| Model Number | PT-S20KW |
| Part Number | PT-S20KW |
| UPC | 818742014199 |
| Connector Type | Quick Connect |
| Contact Material | Copper |
| Contact Type | Normally Open |
| Mounting Type | Socket Mount |
| Operation Mode | Electric |
| Coil Voltage | 24 Volts |
| Maximum Switching Voltage | 24 Volts |
| Minimum Switching Voltage | 24 Volts |
| Item Weight | 4.2 ounces |
| Package Dimensions | 3.35 x 2.8 x 2.24 inches |
| Manufacturer | OneTrip Parts |
9. Warranty and Support
9.1 Warranty Policy
This PROTACTOR Electric Furnace Sequencer is covered by an exclusive Protactor two-year limited replacement policy. If this part fails within two years from the date of purchase, return the defective part along with a copy of the original invoice to the place of purchase for a replacement.
For detailed information regarding the warranty claim process, please contact the authorized Protactor dealer from whom the part was purchased.
9.2 Customer Support
For technical assistance or further inquiries, please contact your authorized PROTACTOR dealer or the manufacturer, OneTrip Parts.