How to Replace an Intermatic T104 Mechanism

WRITTEN BY:  Inyo Pools

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The mechanism in an Intermatic T104 timer will occasionally fail. It is time to replace the mechanism if the yellow wheel stops turning and the manual switch no longer functions correctly. The following steps will provide a guide on how to replace the T104M.

Things You'll Need

Step by Step


Step 1

TURN OFF THE POWER TO THE TIMER BOX. There should be a circuit breaker before the timer box where the power can be turned off.

Step 2

Inside the Intermatic T104 box, remove the black plastic insulator. The insulator is held in place by one screw.

Step 3

With a flathead screwdriver, loosen the screws that hold the ground cables and power cables in place. Pull the cables away from the Intermatic mechanism.

Step 4

Compress the tab at the top of the box that holds the mechanism in place.

Step 5

Pull the Intermatic T104 mechanism out of the box.

Step 6

With the new T104M in hand, press the mechanism back into the timer box.

Step 7

Connect the ground wires to the green screw located on the Intermatic timer mechanism. The ground wires will be green or exposed copper. One ground will be coming from the breaker and the other will be from the equipment.

Step 8

Locate the two input power cables that come from the breaker. Connect one to terminal 1 and the other to terminal 3. Terminals 1 and 3 are called the "Lines". Note: it does not matter what color goes to 1 or 3. It only matters that one cable is on 1 and the other is on 3.

Step 9

Connect the cables running from the equipment to terminals 2 and 4. One cable will go to teminal 2 and the other to terminal 4. Terminals 2 and 4 are called the "Loads". The Loads are what the timer controls. Note: it does not matter what color goes to 2 or 4.

Step 10

Place the black plastic insulator back into the box and tighten the screw to keep it in place.

Step 11

Turn on the power at the circuit breaker.

Step 12

The Intermatic T104M mechanism should now be successfully installed. Close the timer door and continue to enjoy the energy savings of using a timer.



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