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

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I am having problems with my timer. The manual override is in the on position but the pump is not working. I have to manually turn it off and then on again to get it to work which it doesn't alway

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  • Intermatic Master
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Posted on Jan 02, 2017

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SOURCE: pump won't turn on

i think the timer is bad since u can't manually override it

Posted on Aug 22, 2009

  • 1305 Answers

SOURCE: intermatic t10004 control panel trips the circuit breaker

That circuit breaker is letting you know that you've got a problem in the electrical wiring.... What's next is to turn the power off to BOTH legs of the breaker.
Begin by physically inspecting all the connections in the timer box, and at the breaker and all the way to the pump motor. Make sure all connections are dry, and there's no water in any of the conduits...this will cause a short circuit and trip the breaker. If there's any bare power leg wires touching a grounding point , this can cause the breaker to trip. Lastly check the motor on the pump; on the motor end, there should be a cap you can remove and use a crescent wrench to make sure the motor shaft is moving freely. It could be jammed with debris....this happens around my pool often because I'm surrounded by trees with needles. If the motor cannot turn freely, this will cause the breaker to blow... I'm pretty sure that your timer isn't the issue... Please let me know what you find out.

Posted on Nov 19, 2009

  • 43501 Answers

SOURCE: I have a 120v pool pump. I have replaced the

All that I can think of off hand is that you either have two off trippers or the on tripper is not the right one...they should say on and off right on the tripper...

You can see that is this picture...

If you have the right trippers then I would check to see why the on tripper is not contacting the lever to push it to the on position... is the motor too weak and stalling out when if hits the lever?
I have installed many of these timers and they usually work flawlessly...
I hope that this gives you enough info to figure out what is going on with your timer.


Posted on Aug 16, 2010

SOURCE: I have the same above T104 Mechanical Time Switch.

If i understand correctly, you have T104 240V timer that has worked fine in the past.
If this is true, then breaker is correct size.

If this is new installation, then check wiring at timer, and then add up total watts of Load and divide by 240 to check if breaker is sized correctly

If timer worked fine in the past: It seems you have a short somewhere, which is puzzling why it trips when when timer turns OFF.
And the short could be inside a bad breaker -or- inside the timer -or- possibly a wire.
Move wires from 240Breaker to another same-size 240V breaker and see if problem persists.

After moving wires to another breaker, use manual override to check if suspect is the breaker or possibly a short in the timer.
Absolutely stand on dry surface or dry boards when working on this timer, to be on safe side.
Manual override should switch Load on-off, and override should snap clean and crisp each time.
If manual override lever is not crisp, then that signals timer has gone bad.

Also snap mechanism out of box using thumb-spring at top of box, and look for signs of burning and high heat, especially at contacts.

If you buy new timer, the inside mechanism can be swapped out without changing the box.

Add a comment and let me know what you find out, and I will respond if needed.
This is interesting puzzle.

Posted on Feb 03, 2011

  • 2510 Answers

SOURCE: installed new t104m timer .

It sounds like there is a problem with the wiring and a neutral is running to earth when the pump switches on. Below is a diagram of the wiring. The wiring would be the same for 110 v.


Posted on May 13, 2011

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Switch moves into on position but not enough to energize line. I have to manually move switch 1/4 of an inch

1) If manual override lever does not manually click back and forth crisp and clean, then timer parts are bad or dirty: Turn off power, and blow out the timer, and then spray WD40. Replace timer.

2) If manual override works fine when moved manually, then trippers are probably worn and need replacement. Trippers are made of softer metal so they wear down before the timer wears out. Replacing trippers and clock motor can keep timer working for decades.

Open following link for Intermatic troubleshoot:

Jul 31, 2011 | Intermatic & Indoor/Outdoor Rain Tight...

1 Answer

The Manual lever does not shut off the pool pump. Ther is something I can do to fix it or I need to replace it? The timer is only one year old

Open following link to troubleshoot Intermatic timer:

Manual override should absolutely turn off pump, especially if everything worked correctly before.
There is an exception. IF there is internal short to ground inside the pump. Turn circuit breaker off, and then at the timer, disconnect ground wire going to the pump, turn breaker back on, and see if pump stops using manual override.

Very odd that such a durable mechanical timer would go bad in 1 year.
The manual override lever actually pushes the contacts together and pulls them apart, so burned contacts cannot stick together. You can check this by turning off power and then remove timer mechanism using thumb spring located top inside box.

If override lever does not function correctly, then timer mechanism needs to be replaced.
Usually it's cheaper to buy whole timer and then install timer mechanism into old enclosure.

Add a comment and say what you discover about this problem.

Jul 26, 2011 | Intermatic & Indoor/Outdoor Rain Tight...

1 Answer

Pool pump starts randomly (as if there is a short) even when it is not set to start and stop. Otherwise works fine, not sure if I need to replace unit or dissassemble and clean or ????? T21004R

Sounds like 240Volt WG1573 clock motor has gone bad and needs replacement. But more checking is needed.

You posted under T2100-4R which is 60 amp Intermatic control panel with a single T104M 240Volt timer mechanism.
All Intermatic timer mechanisms can fit into same control center, so you can possibly have different timer mechanism inserted into the T2100-4R control center.
The control center can have up to 4 circuit breakers.
Instruction manual shows that timer can also have fireman's switch that is wired to pool heater and causes pool heater to turn off 20 minutes before pool pump turns off.

(1) First thing: If you have T104 mechanism, do a troubleshoot run-down to see if trippers, clock motor, or wiring are suspect:

(2) Next would be to check the circuit breakers for loose wires, burned connections, or the smell of burning or crackling sound that says breaker is loose on the busbar.

(3) Check for loose wiring on T104 and test circuit:
(a) Push the manual override lever to OFF position and test across terminals 1 and 2 and then across terminals 3 and 4 to make sure timer is turning off power to pump. Both tests should show 0 volts.
(b) Push manual override lever to to ON position and repeat test above. Both tests should show 240 volts.
If the test fails, then buy new T104M timer mechanism.

(4) If the T104 timer is turning off both lines in the 240Volt circuit, then pump cannot turn on since neither wire is Hot.
However if your T104 timer is actually a T101 timer or if timer has different wiring, where timer is turning off only 1 leg and not both legs of 240Volt circuit, then pump has one hot wire available and a short to ground could cause pump to turn on unexpectedly.

Jul 08, 2011 | Intermatic T21004R- Pool-Spa Mechanical...

1 Answer

I have outdoor T101 in gray steel box that controls on/off of my pool pump/filter.. Timer/clock is working. I am finding that on manual shut off to work on pool filter, when power put back on using...

I don't think the timer is causing the problem.
There is no delay switch on the timer or inside the household electrical circuit breaker or household wires.
The contact point(s) located on back of timer mechanism are mechanically pushed together and pulled apart with the manual override lever.
You can test timer:
Test across terminals A and 1 should show continuous 120V no mater what position override lever.
Flip override to OFF, then test terminals A and 2 should show 0 volts.
Flip override to ON, then test terminals A and 2 should show 120V: If A and 2 show 120Volts and pump is not ON, then problems is between timer and pump or at pump.
Look at wiring terminals on timer. Only copper wire should be under the screw plate. No insulation under screw plate. Two different size wires on same terminal will cause loose connections. Stranded wire and solid copper wire under same screw plate will also cause loose connections.

Sounds like a loose wire or short at the circuit breaker box, timer wiring terminals, or at pump.
Check all screw terminals and wire nuts. Look for smell or signs of heat and burning. Look for connections where two different size wires are connected. Look for connects where stranded wire and solid copper wire connect.
Add a comment for more help.

Jul 07, 2011 | Intermatic T101 - 24 Hr. Dial Time Switch...

1 Answer

I have an Intermatic WH-40 timer set up on swimming pool pump. I am not using any start/stop mechanical pieces on the dial face. Yet my pump does shut off everyday for short time period. Why is this...

Sounds like pump issue or loose wire and not the timer.
Check wiring at pump. Read pump manual. The pump may have overheat cycle that trips off and then comes back on to protect pump without requiring owner to press reset button each time.

If timer turns OFF, then the manual override lever moves to the off position, and when timer turns ON again, the override lever moves to the on position. If override lever is moving without a tripper, then I would like to know more about that. Add a comment with photo posted on Flickr.

Same with the circuit breaker. The circuit breaker switch does not trip and reset once a day.

A loose wire could cause occasional connect-reconnect.
Check terminals inside timer for signs of high heat and burning. Check that insulated part of wire is not under the screw-down-plate.

Check circuit breaker for signs of burning and smell of electrical burning and sound of shorting on the busbar.

Upvote the help.
And take advantage of fixya expert assistance live.
For a price, expert works with you while you work on timer or any do-it-yourself project.
Fixya is always less expensive than a service call.

May 31, 2011 | Intermatic WH40 - Water Heater Time Switch...

1 Answer

My automatic timer is not working.

You posted under Intermatic raintight timer.
Add a comment with your model and brand and I have extensive files on timers.

The best diagnostic is the manual override.
1) Click manual override and see if Load (lights, fan, motor) come on.
If manual override clicks on-and-off crisp and clean, but the lights do not come on, check your electric power.
If the manual override does not click crisp and clean, then the timer may be rusty, or timer may need to be replaced. Buy replacement timer and swap out timer mechanisms without changing the box.
If the manual override works fine, and Load turns on-and-off with manual override, then the clock or trippers are next suspect.

2) Check if the dial is turning as time passes.
If the dial is not turning, then the clock motor is bad and you can buy a new clock motor.
If dial is turning, and manual override turns Load on-and-off, then the tripper pins might be worn out, and you can buy new trippers.

3) To buy replacement parts: Timer door has model number of timer. Timer clock located on back of timer mechanism has identifying numbers. You can snap out the timer mechanism using metal spring locate top inside box.
Grainger sells trippers and motors:
Aplus sells motors:
Intermatic sells motors:

Nov 10, 2010 | Intermatic & Indoor/Outdoor Rain Tight...

1 Answer

The timer clicked OFF but poot pump kept running. Had to trip breaker to stop pool pump.

Your Intermatic timer has a manual override.
The override is a good diagnostic.
Click the manual override and see if pump turns on and off.

Next, watch if the clock is rotating.
If the clock is rotating, the OFF tripper may be worn out and you need a new tripper


If the clock wheel is not rotating, you need a new clock motor.
If you have T104, your clock motor is 240Volts
If you have T101 or T103, your clock motor is 125Volts
Buy trippers and clock motors at Grainger
Clock motor replacement takes a small star-screwdriver bit

If your manual override is not working, then the gears might be rusty and need to be cleaned or your timer needs to be replaced.
You can buy same model number timer and then swap the insides without changing boxes.

Add a comment if you need more help.

Nov 02, 2010 | Intermatic & Indoor/Outdoor Rain Tight...

1 Answer


If I understand correctly, you have Intermatic dial-type timer.
The dial or clock is turning but the timer does not turn ON and OFF.

Here's what to do.
1) Click the manual override to see if Load (lights, fan, motor) comes on.
The manual override is your best diagnostic tool.
If the manual override does not click back and forth very well, then timer is probably bad.
You can buy a new Intermatic and snap the new timer into old box without changing boxes.

2) If the manual override does not turn on the Load, then the electricity to Load is suspect.
a) There could be loose wire inside box or loose wire at Load
b) The breaker to Load could be tripped if the Load operates on different breaker than timer. For example some timers run on a 120V breaker, but the Load is a 240V pool pump.
c) Load is not working. For example the light is burned out.

2) If the manual override works fine and Load goes on-and-off, then you can have 4 possible problems.
a) The tripper pins are not placed on the timer dial
b) Tripper pins are worn down and you need new trippers
c) If this is a new installation, then wiring can be reversed, so check wiring

If you need Intermatic tripper pins:
If you have a T-100 series timer, then the following page shows wiring for those timers

Please write back after you narrow down the suspects.
We'll get your timer running.

Oct 22, 2010 | Intermatic & Indoor/Outdoor Rain Tight...

1 Answer

Pump will run on manual setting but not automatic pins were put on

If I understand correctly, this is a timer that has been in place for a while and is not a new installation?

If timer has operated in the past, then the wiring can be eliminated as a suspect

You say the manual override works correctly. That eliminates the question if timer has power.

We have 2 suspects remaining:
1) The general condition of the timer, whether the gears are rusty and dirty.
Is the manual override snap over fully. Is manual override sluggish or crisp. The tripper pins have to move the same lever as the manual override, so if override is bad, the timer is bad.
Turn off power
Release mechanism using spring located top of box
Tip out timer mechanism and look at gears for rust and dirt
Does it look like the timer is too rusty for the trippers to click the on-off lever?
Look at the back of timer for same problems.
Spray a little WD-40
You can buy a new timer of same type and swap insides without replacing whole box

2) Clock motor
Is the clock wheel turning as time passes? The clock wheel or dial must rotate for timer to work.
You can replace the clock motor
Take mechanism out as described above, clock motor is located on back and has identifying markings
Order a new clock motor of same type:

Upvote if this information helped. Thanks for the feedback.

Oct 18, 2010 | Intermatic & Indoor/Outdoor Rain Tight...

1 Answer

Timer wont turn on, is the manual switch below the dial suppose to be in on or off position?

the manual switch is to override the timer and turn on what its controlling, for the timer part to work it is supposed to be in the off position, this should let the timer work like its supposed to.

Aug 08, 2009 | Intermatic Hardware & Accessories

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