Intermatic T103M 24-Hour Mechanical Timer Mechanism – 120V, 40 Amp, DPST

The Intermatic T103M Mechanical Time Switch Mechanism is a genuine Intermatic replacement timer designed for automatic 24-hour scheduling of swimming pool pumps, lighting, and other compatible electrical equipment. Featuring a 120V AC clock motor and heavy-duty 40-amp double-pole, single-throw (DPST) switching contacts, this timer provides reliable daily ON/OFF control.

Part of the popular Intermatic T100 Series, the T103M is designed to replace a compatible timer mechanism inside an existing approved Intermatic enclosure. Its mechanical dial, adjustable trippers, and manual override lever make it easy to schedule equipment operation without digital programming.

This product includes the timer mechanism only. An electrical enclosure is not included.

Product Features

• 24-Hour Mechanical Timer: Repeats the programmed ON/OFF schedule every day.
• 120V AC Clock Motor: Operates on 120 volts, 60 Hz.
• 40-Amp Switching Capacity: Heavy-duty contacts for compatible electrical loads.
• Double-Pole, Single-Throw (DPST): Controls two poles simultaneously.
• Up to 12 ON/OFF Cycles Per Day: Supports multiple switching periods when equipped with additional compatible trippers.
• One-Hour Minimum Switching Interval: Suitable for daily equipment scheduling.
• Manual Override Lever: Allows equipment to be switched ON or OFF without changing the next scheduled operation.
• ON and OFF Trippers Included: Comes with one ON tripper and one OFF tripper.
• Replacement Mechanism: Designed for installation in compatible Intermatic enclosures.
• Genuine Intermatic Product: Original manufacturer mechanical timer assembly.

Product Specifications

• Manufacturer: Intermatic
• Manufacturer Part Number: T103M
• Series: T100 Mechanical Time Switches
• Product Type: 24-Hour Mechanical Timer Replacement Mechanism
• Clock Motor Voltage: 120V AC
• Frequency: 60 Hz
• Switch Configuration: DPST (Double-Pole, Single-Throw)
• Resistive / Inductive Load Rating: 40 Amps, 120–277V AC
• Motor Load Rating at 120V: 2 HP, 24 FLA
• Motor Load Rating at 240V: 5 HP, 28 FLA
• Scheduling: 24-Hour Daily Repeat
• Minimum ON/OFF Interval: 1 Hour
• Maximum ON/OFF Cycles: 12 Per Day
• Manual Override: Yes
• Included Trippers: 1 ON / 1 OFF
• Enclosure: Not Included
• UPC: 078275000254
• Country of Origin: Mexico
• Manufacturer Warranty: 1-Year Limited
• Quantity: 1 Timer Mechanism

Common Applications

• Swimming pool pump scheduling
• Pool and spa circulation equipment
• Outdoor lighting controlled through an appropriate enclosure
• Landscape and security lighting
• Compatible motors and electrical equipment
• Replacing damaged or nonfunctioning Intermatic T103 timer mechanisms

120V Clock Motor with DPST Switching

The Intermatic T103M uses a 120V AC clock motor to advance its mechanical dial. Its DPST switch contacts can simultaneously open or close two poles of a compatible electrical circuit.

Important Voltage Distinction: The T103M requires 120V power for its clock motor, even when controlling an appropriately rated 240V load. Do not connect the clock motor directly across a 240V supply.

For installations requiring a 208–277V clock motor, the Intermatic T104M is a different timer mechanism that may be appropriate after verifying the electrical application.

Easy 24-Hour Scheduling

The T103M features a mechanical clock dial with adjustable ON and OFF trippers. The timer automatically repeats its scheduled switching operations every 24 hours.

To adjust the schedule:

1. Disconnect electrical power before accessing wiring or servicing the mechanism.
2. Position the ON tripper at the desired equipment start time.
3. Position the OFF tripper at the desired equipment stop time.
4. Secure both trippers firmly to the dial.
5. Set the current time by following Intermatic's dial-setting instructions.
6. Restore power and verify correct timer operation.

Additional compatible trippers can be installed to create multiple ON/OFF periods throughout the day.

Related Intermatic Replacement Parts

Complete your timer repair with these related Intermatic products available from Aqua Pool Supply.

• Intermatic 156T1978A – Replacement Timer Trippers – Replacement ON/OFF trippers for compatible T100 Series mechanical timers. Useful for replacing lost trippers or adding switching periods.
• Intermatic WG1570-10D – 125V Replacement Clock Motor – Genuine replacement clock motor for compatible 120V Intermatic mechanical timers, including applicable T103 mechanisms.
• Intermatic T104M – 208–277V Mechanical Timer Mechanism – Alternative DPST mechanical timer for installations requiring a higher-voltage clock motor. Not a direct electrical replacement for the 120V T103M.

Replacing an Existing Timer Mechanism

The Intermatic T103M can be installed in compatible Intermatic timer enclosures, making it useful when an existing mechanism has failed but the enclosure remains suitable for service.

Before purchasing, confirm the original timer model, clock motor voltage, switch configuration, electrical load ratings, and enclosure compatibility.

Installation should be performed by a qualified electrician following Intermatic's wiring instructions and applicable electrical codes.

Additional Intermatic Pool Timer Products

Explore our Intermatic Pool Timers and Replacement Parts for mechanical timer mechanisms, clock motors, trippers, and pool equipment controls.

Package Contents

• One (1) Intermatic T103M 24-Hour Mechanical Timer Mechanism
• One (1) ON Tripper
• One (1) OFF Tripper

Important: This listing is for the T103M replacement mechanism only. An electrical enclosure, additional trippers, and other installation accessories are not included.

Compatibility Notice: The T103M requires a 120V AC, 60 Hz clock motor supply. Verify the existing timer's voltage and wiring before replacing it. Intermatic T101M, T103M, and T104M mechanisms have different electrical configurations and should not be treated as interchangeable.

Electrical Safety: Disconnect all power before installation or service. The timer must be installed in an approved electrical enclosure by a qualified electrician in accordance with Intermatic instructions and applicable electrical codes.