Question about Intermatic T104 24h 208-277v Mechanical Time Switch

2 Answers

A t104 intermatic turns on and off sporadically

The timer turns itself on and off withou trippers or lever moving. Any idea how to fix this? It will turn on and off while it should be off.

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  • Jim Fox
    Jim Fox Jan 13, 2009

    The timer is controllng an in-ground swimming pool pump.

  • Jim Fox
    Jim Fox Jan 26, 2009

    Thanks. This timer has metal trips and it starts and stops at times when it is not even close to the trip levers. The trip levers work as they should, when they should. On a warm day I will pull the cover off, clean it, etc.

  • Hippy_dd May 11, 2010

    what do u have it hooked up to, what is it controlling.



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Some more things to check,

check to see if the pump has power on it, when it is not running.

make sure all ur connections are good.

if u have no power when it is supposed to be on the timer itself could have a short internally

Posted on Mar 22, 2009

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Replace the trip levers, I dont think your timer turns off and on without trip levers? Unless your outdoor fixtures have photo cells on them or wired to them! Are they coming on at night and shutting off at Daylight, if so they are connected to a photocell or have internal photocells which means you don't need the timer unless you want to control different on off times.

Posted on Jan 26, 2009

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1 Answer

Intermatic T104 timer manual switch stuck

To remove timer from enclosure, there is thumb spring located top inside box. Push up on spring, hold onto timer dial, tip outward and lift upward.
Disconnect power before removing mechanism.
Override lever should snap back and forth crisply, and turn pump ON-OFF.
If override lever is not turning pump ON-OFF, then check that you have 240Volts across terminals 1 and 3. Check that timer dial is rotating and keeping good time.
Then move override lever to ON position and check if you have 240Volt across terminals 2 and 4. These terminals are Hot when pump is supposed to be ON.
Reset circuit breaker, may be tripped off on one leg, listen for crackling sound of loose breaker, use nose to smell for burning, tighten wires on breaker, move wires to another same-size circuit breaker.
Copy following links for troubleshoot resources:

If timer is not functioning, then buy clock motor and trippers.
OR. You can buy the T104M mechanism-only, and snap into existing enclosure.
OR. It may be cheaper: Buy the whole T104 and snap out of new enclosure and install mechanism into existing enclosure.

Jul 19, 2012 | Intermatic T104 24h 208-277v Mechanical...

1 Answer

Ti04 clock rotates and new trippers but doesn't turn on

You probably have T104 timer.
Clock rotates so power to timer motor is good. This means 240Volt breaker is good.
Use override lever and see if Load (light, fan, motor) turns on and off. If override does not turn Load on-off, then bypass timer and see if load works. Move wires from terminal 2 to terminal 1, and terminals 4 to terminal 3.
Did you order correct trippers?
Copy following links for Intermatic troubleshooting and Intermatic parts list.

Jun 28, 2012 | Intermatic T104 24h 208-277v Mechanical...

1 Answer

When setting my timers should the manual switch be left in the on or off position?

Either position is fine.
The override is not permanent ON or OFF since it moves back and forth when trippers pass.
The trippers push a lever back and forth that opens and closes electrical circuit.
When the lever moves back and forth, it also clicks the override back and forth with audible sound.
If the timer is ON, you can move the override to OFF.
When the next ON tripper rotates around, it will move the override back to ON.
So the override just temporarily overrides the timer function.

Jun 21, 2011 | Intermatic T104 24h 208-277v Mechanical...

1 Answer

I have an intermatic T104P3 timer for my pool and now it won't turn on. I have to start the pool on manual. I have tryed to remove the screw to start and it goes right by it and does not set the pool on....

Hi Dianna, I am timer expert at Fixya

1) When you say screw, I believe you mean tripper?

2) Trippers are placed on dial using thumb screw. Clock motor located on back of mechanism rotates dial. So dial rotates as time passes.
On-off trippers rotate around on the dial and push a lever back and forth that turns pump on-off.
Trippers are designed to wear down so that timer mechanism lasts longer.
You can buy replacement trippers for T100 series timers at Grainger:

3) You posted under T104 timer.
Notice that grainger also sells WG1573 240Volt clock motors for the T104.
Clock motors slow down and burn out.
Clock motors are replaced by tipping mechanism out of box using thumb spring located inside box at top. Clock motor is attached with 2 small star screws. Buy star screwdriver at auto parts or hardware.
When ordering trippers, you might want extra clock motor on hand for when the dial stops rotating.

4) Open following link to see manual and wiring instructions for T104.

Add a comment for more free help.
Also take advantage of fixya phone service.
For a price, expert speaks with you over phone while you work on timer or any do-it-yourself project.
Fixya is always less expensive than a service call.

Feb 10, 2011 | Intermatic T104 24h 208-277v Mechanical...

1 Answer

Can't figure out how to set the times to turn power off/on.The metal trippers seem to be permanently in there.

Remove dial from body of timer.
So now the timer is apart in 2 pieces.
Silver ON trippers and brass OFF trippers can be removed.

Place trippers in times you want timer to operate.
OFF trippers have to be at least 2 hours apart.
ON trippers have to be at least 2 hours apart
Minimum on-off function is one hour

Snap timer back together.

Tripper rotates around with dial.
When tripper contacts on-off lever, it physically moves lever like turning on light switch.
ON tripper moves lever one direction.
OFF tripper moves lever opposite direction.

Manual E-1020

Dec 11, 2010 | Heavy Duty Intermatic Wall Switch Timer...

1 Answer

I HAVE AN iNTERMATIC t100m TIMER it appears to have two "off" tripper levers but no "on" tripper lever attached to the clock face dial by a set screw . Do I need an "on "...

Yes, the T101M 120Volt pool timer requires both ON and OFF trippers:

Grainger sells T100 series on-off trippers:
Amazon sells T100 trippers

Grainger sells the T100 125V clock motor

How to wire T-101 120Volt timer

How Intermatic dial timer clock works.
Clock motor rotates dial.
Intermatic clock motor, located on back of mechanism, are replaceable
Trippers located on outer edge of dial push on-off lever
ON tripper pushes lever one direction
OFF tripper pushes lever opposite direction.
Lever pushes electrical contacts together and pulls contacts apart.
When lever moves, manual override also clicks back and forth with audible click.
To replace timer, replacement snaps into box without needing to changing box.

Dec 10, 2010 | Intermatic T101 - 24 Hr. Dial Time Switch...

1 Answer

Power is good going into the timer but the timer is not running. I am wondering if there is a fuse that needs to be changed or a reset switch? The timer has been replaced in the last year.

If I understand correctly, you have T-104 240V timer.
Timer was running fine before, and recently stopped working.
If this is not your timer, add a comment.

1) Click manual override back and forth to see if Load turns on-off.
If Load does not turn on-off, then check power at Load.
Timer has 5 terminals A 1 2 3 4
Check terminals 2 and 4 for 240Volts when Load is ON

2) Check terminals 1 and 3 for 240Volts to make sure timer has full 240V and breaker is not tripped OFF on one leg. If timer has 120V, it appears to have voltage, but clock will not rotate and Load will not turn on-off. Check breaker for 240V across both screws.

3) Is dial rotating?
If dial is not rotating or is stuck in place, replace 208-277V clock motor.

4) If dial is rotating, but trippers don't flip on-off lever, then trippers may be worn down. Buy new trippers.

5) How to wire T104 timer

How timer works
Clock motor rotates dial.
ON-OFF trippers on dial contact lever.
ON tripper pushes lever one direction.
OFF tripper pushes lever other direction.
Lever moves electrical contacts together, or pulls contacts apart.
When lever moves on-off, manual override lever also snaps back and forth with audible clicking sound.


Nov 24, 2010 | Intermatic T104 24h 208-277v Mechanical...

1 Answer

How do I reset the time needle on my intermatic modle t101 The screw was loose and the needle move so

T101 Intermatic is 120Volt electro-mechanical timer

Silver pointer is located at 6:00 position.
Tighten the center screw with star screwdriver
Lift and rotate yellow dial until current time lines up with silver pointer.


How electro-mechanical timers work:
Place ON-OFF trippers on dial.
Trippers rotate around with passing time.
Trippers encounter on-off lever.
OFF tripper clicks lever one direction.
ON tripper clicks lever other direction.
Manual override lever clicks back and forth each time on-off lever is clicked.
How to wire T101:


Nov 16, 2010 | Intermatic T101 - 24 Hr. Dial Time Switch...

1 Answer

"off" tripper works. "on" tripper has stopped working. have tried two other "on" trippers that work on other units, but they do not work either.

If the manual override works correctly then wiring is good
The manual override connects to same lever that trippers push to operate timer, so manual override is a good diagnostic.
The ON-Off trippers push a lever one direction, and then the other tripper pushes lever other direction.

If the the ON tripper will not push the lever, then you need a new tripper >>> but you have put in trippers that work on another timer, and they don't flip the lever either. It sounds like the lever is worn out.

Once the lever is worn out, the timer needs replacement.
Buy another T-104 or T-104R, and then swap out insides without changing the box.

Grainger sells the T104 replacement timer without box
Grainger sells accessories for Intermatic timers

Oct 24, 2010 | Intermatic T104 24h 208-277v Mechanical...

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