How to Replace an Intermatic T104 Mechanism


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With time the gears in an Intermatic T104 timer mechanism may become loose and start to jam causing the yellow wheel to stop turning. To correct this problem you have to replace this T104 Mechanism. The following steps show you how to replace the T104 Mechanism. Note, this guide is for a T104 220V timer. If you have a T101 110V timer, use the T101 Mechanism.

Click here to view the T100 timer parts. 

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.

Click here to view the T100 timer parts. 

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.

Click here to view the T100 timer parts. 

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.

Click here to view the T100 timer parts. 

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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 Posted: 4/10/2019 

Good info. I replaced my T104 R after 12 years the clock stopped working. I took pictures of the wiring and with your step by step guide I changed in in about 15 minutes. That included a new box. Unfortunately the new timer clock does not work although the manual switches do. I had an electrician come by today and he confirmed all electrical components are correctly connected, breakers are fine and all wiring has power. He said the clock just isn't working. So, back to Loews tomorrow. I hate having to do things twice.

InyoPools Product Specialist  Posted: 4/15/2019 

Sorry to hear that. Maybe you got a timer with a defective motor. We wish you better luck with the replacement.