1. Introduction
This manual provides detailed instructions for the installation, operation, and maintenance of the Intermatic DTAV40M Auto Voltage Defrost Timer. The DTAV40M is designed for use in air defrost (compressor shutdown) and electric or hot gas defrost systems. It features a fail-safe mechanism that terminates the defrost cycle if temperature or pressure switches do not respond as expected. Please read this manual thoroughly before installation and use to ensure proper function and safety.
2. Safety Information
WARNING: Risk of electric shock. Installation and servicing must be performed by qualified personnel only. Disconnect power at the circuit breaker or fuse box before installing or servicing this device. Failure to follow these instructions could result in serious injury or death.
- Always ensure the main power supply is disconnected before working on electrical connections.
- Verify all wiring connections are secure and comply with local and national electrical codes.
- Do not operate the timer with damaged components.
- This device is intended for indoor use within a NEMA3R enclosure or equivalent protection.
3. Product Overview
The Intermatic DTAV40M is a robust defrost timer mechanism designed for reliable control of defrost cycles in various refrigeration and HVAC applications. Its auto-voltage feature allows for flexible installation across 120V to 240V systems.
Figure 1: Intermatic DTAV40M Defrost Timer Mechanism
This image displays the internal circuit board of the Intermatic DTAV40M Defrost Timer. Prominently featured is a circular clock dial with hour markings (1-12 AM/PM) and a series of adjustable pins around its circumference for setting defrost cycles. Below the dial, two red indicator LEDs are visible, labeled 'REFRIG' and 'DEFROST', indicating the current operational mode. A terminal block with screw terminals labeled 'F', '3', '1', '2', '4', 'N', and 'X' is located at the bottom, used for electrical connections. Various electronic components such as capacitors and resistors are also visible on the green circuit board.
Key Features:
- Auto Voltage: Operates on 120V to 240V AC.
- High Amperage: 40A resistive, 2Hp at 250Vac relay output.
- NEMA3R Enclosure Compatibility: Designed for use in outdoor environments when properly housed.
- Defrost Termination: Timer-terminated, with optional temperature or pressure switch termination for efficiency.
- Fail-Safe Mechanism: Ensures defrost cycle termination even if external sensors fail.
- Synchronous Timer Type: Provides accurate timekeeping.
4. Installation
Installation should only be performed by a qualified electrician in accordance with all applicable national and local electrical codes. Ensure the power supply is disconnected before beginning installation.
Mounting:
- Select a suitable NEMA3R rated enclosure for outdoor installations, or an appropriate enclosure for indoor use.
- Mount the DTAV40M mechanism securely within the enclosure using the designated mounting points.
- Ensure adequate ventilation and clearance around the timer for proper operation and heat dissipation.
Wiring:
Refer to the wiring diagram provided with your specific unit or consult a qualified electrician. The terminal block at the bottom of the unit (as shown in Figure 1) provides connections for power input, load output, and optional control signals. Typical connections include:
- F: Fan connection (if applicable)
- 3, 1, 2, 4: Load connections for compressor, defrost heater, etc.
- N: Neutral connection
- X: Line voltage input
Note: The exact terminal functions may vary based on the specific application and system configuration. Always consult the full wiring diagram for your installation.
5. Setup and Programming
The DTAV40M timer uses a mechanical dial for setting the time of day and defrost cycles.
Setting the Time of Day:
- Rotate the inner clock dial clockwise until the current time aligns with the time indicator arrow (usually a small triangle or line on the timer housing).
- Ensure to differentiate between AM and PM hours as indicated on the dial.
Setting Defrost Cycles:
- The outer ring of the clock dial has a series of captive pins. These pins control the defrost cycles.
- To initiate a defrost cycle, push a pin inwards towards the center of the dial. Each pin typically represents a 15-minute interval.
- To end a defrost cycle, ensure the pin is in the outward position.
- Set the desired number and duration of defrost cycles by pushing in the appropriate pins corresponding to the required defrost times.
6. Operation
Once installed and programmed, the DTAV40M will automatically manage the defrost cycles. During normal operation, the refrigeration system will run. When a programmed defrost time is reached, the timer will switch the system into defrost mode, activating defrost heaters or shutting down the compressor as configured.
- The REFRIG LED (if present) indicates the refrigeration cycle is active.
- The DEFROST LED (if present) indicates the defrost cycle is active.
- The timer will terminate the defrost cycle after the set duration or if a temperature/pressure switch signals completion (whichever comes first). The timer acts as a fail-safe, ensuring termination even if sensors fail.
7. Maintenance
The Intermatic DTAV40M is designed for long-term, reliable operation with minimal maintenance. However, periodic inspection is recommended.
- Annual Inspection: Visually inspect the timer and its connections annually for any signs of wear, corrosion, or loose wiring.
- Cleaning: If necessary, gently clean the exterior of the timer with a dry, soft cloth. Do not use liquid cleaners or solvents.
- Functionality Check: Periodically verify that defrost cycles are initiating and terminating as programmed.
8. Troubleshooting
If you experience issues with your DTAV40M defrost timer, refer to the following common problems and solutions:
| Problem | Possible Cause | Solution |
|---|---|---|
| Timer not running / No power | No power supply; loose wiring; faulty circuit breaker. | Check power supply at the source. Verify all wiring connections are secure. Reset circuit breaker. |
| Defrost cycles not initiating | Incorrect pin settings; timer not set to current time. | Ensure defrost pins are pushed in for desired times. Verify the current time is correctly set on the dial. |
| Defrost cycles not terminating | Defrost duration too long; faulty temperature/pressure switch (if used). | Check pin settings for defrost duration. If external sensors are used, inspect their functionality. The timer's fail-safe should eventually terminate the cycle. |
| Inaccurate timekeeping | Power interruptions; internal mechanism issue. | Reset the time after any power outage. If problem persists, the unit may require replacement. |
If troubleshooting steps do not resolve the issue, contact Intermatic customer support or a qualified service technician.
9. Specifications
| Model | DTAV40M |
| Brand | Intermatic |
| Voltage | 120-240V AC |
| Amperage | 40A Resistive, 2Hp at 250Vac |
| Enclosure Rating | NEMA3R (when installed in appropriate enclosure) |
| Operating Temperature | -4°F to 104°F (-20°C to 40°C) |
| Electrical Life | 50,000 operations at full load |
| Dimensions (Approx.) | 2"D x 2"W x 5"H |
| Material | Plastic |
10. Warranty and Support
For warranty information, please refer to the documentation included with your purchase or visit the official Intermatic website. For technical support or further assistance, contact Intermatic customer service directly. Keep your proof of purchase for warranty claims.
Intermatic Contact Information:
- Website: www.intermatic.com
- Refer to the product packaging or Intermatic website for specific phone numbers and support hours.
