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Norm
Norm, Master Electrician
Category: Electrical
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Experience:  Registered professional electrical engineer and licensed master electrician.
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I have an Intermatic ET1105 timer that I want to control a

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I have an Intermatic ET1105 timer that I want to control a sprinkler pump. I have 240v line coming from panel (2 line wires) and 2 wires out to pump (2 load wires). I selected 240v on timer voltage selector. the timer has 4 terminals. I connected line 1 to terminal 1, Line 2 to terminal 2, Load 1 to terminal 1, load 2 to terminal 4, Jumper wire from terminal 2 to terminal 3. I turned on the breaker & selected manual mode on timer & pressed the on/off button, but pump doesn't run. Do I have this connected properly?

Norm : An interesting question. To start off, you have the wrong timer for 240 Volt operation. The ET1105 is a single pole, single throw model which interrupts only one of the two lines when used for 240 Volt loads as you are doing. This leaves the remaining line connected when the timer is off, an unsafe condition. The timer you should have is the ET1125 double pole double throw model. That being said, the connection you describe should work unless the timer has some built-in logic to detect the fact that a 240-Volt load is being switched, which I doubt. I could find nothing in the Intermatic literature that would suggest the timer is that smart. Are the backup batteries installed? It may not work at all without them.
Norm : Norm
Customer: Thanks for that response, but why does it have a 240v selection on the voltage switch then?
Customer: yes tha batteries are installed.
Customer: It says it is the model to use to connect a hot water heater or a pump.
Customer: The diagrams in the documentation that comes with it is not very good.
Norm : Hi again,
Norm : Hi again. I think the multiple voltage availability for all timer models is a convenience for the manufacturer so that they have to stock fewer circuit boards. Here's a link to a website with diagrams for the timers: http://www.intermatic.com/~/media/Intermatic/Documentation/Time%20Switches/Electronic%20Time%20Switches/24%20Hour/ET1100%20Series/ET1100%20Series%20Instructions.ashx
Norm : You'll see from the diagram for the ET1105 that it is connected to a supply with one grounded conductor, which does not have to be interrupted. The only way this time could control a water heater safely is to use a relay.
Norm and 2 other Electrical Specialists are ready to help you
Customer: replied 4 years ago.
Thanks for the help, I have ordered the ET1125 model timer. It looks like I should install this like the 1125 240v DPST example in the documentation (bottom left example)with the 2 jumper wires.
Sounds great. That should do the job safely.

Norm

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