Contactor switch.

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Old 01-23-15, 10:22 AM
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Contactor switch.

I have a Spa heater that is 240 V 50amp. the contactor that I removed is a 2 pole. I had a contactor in my garage that is a 3 pole 240 v 50 amp. Does it matter if one of the poles is not in use on the contactor? I hooked it up leaving the center pole empty. The pressure switch and the thermostat were working before. If i depress the magnetic center manually on the contactor, I get proper voltages across the contactor however it wont automatically work. so I guess the question is... Does it matter if one of the poles is not in use on the contactor?
 
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Old 01-23-15, 10:40 AM
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Welcome to the forums.

If you had the room you could use a three pole contactor in place of a two pole one with no problem.
Contactors are available with different voltage coils. Your replacement must match the original.

What is the problem with the old contactor ?
If it won't engage... check the coil for continuity with the AC power turned off.
Likewise... check the leads for power when it should be engaged.
 
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Old 01-23-15, 11:18 AM
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thanks for the quick response, the voltage coils are the same 208/240. the orientation of the terminals of the coils are different. the old two pole contactor had spade terminals on the sides, and the one i am trying to use has the spade terminals only on the top. the old contactor had a melt-down. the wires leading from the main bus to the high temp reset switch are good, from there they go to the contactor. One of the 8 ga. wires got weak and partially melted in half. the heat from this, melted the plastic that holds the moving part of the contactors in place misalignment resulted and the contactor pads would no longer touch when engaged. I must have one of the wires from the coil spade terminal in the wrong place because of the different orientation.
 
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Old 01-23-15, 12:08 PM
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I triple checked the wire paths, it all checks out. I can by-pass the contactor and the unit heats up fine, it just wont shut off because I by-passed the thermostat. I am using poles 1 and 3 leaving the center one empty. I will rewire it to use 1 and center to see if it makes any difference and post results.
 
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Old 01-23-15, 12:34 PM
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that didn't work either. I did check power across the coil spade terminals with the contactor manually engaged and it was zero. I do have a wire running to the right side of the coil terminal that is hot, but the left side is not getting power, any Ideas ?
 
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Old 01-23-15, 02:31 PM
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Can you post a pic of that Contactor,what's the coil voltage ?where is that coil getting it's power,it could be from that center leg.
Geo
 
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Old 01-23-15, 02:36 PM
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I do have a wire running to the right side of the coil terminal that is hot,
When you turn the pump off... does that voltage drop out ?
You need to determine if they are switching power and if you lost the other leg.

BUT if you measure voltage on one side of the coil.... it should carry thru the coil and be measurable on the other side as well. If not.... the coil is open.
 
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Old 01-23-15, 03:39 PM
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The coil is open. I have a wire leading to the coil from the load side that is hot. for some reason i cant upload pictures, tried multiple ways says error. I ordered another contactor and will post on Tue. if it fixes the problem thanks to all of you for the time invested in helping me. I will post results then. thanks again. John
 
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Old 01-23-15, 04:40 PM
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The forums will only accept pictures of 100kb and smaller. It will resize the 100k to the board max of 50kb.

Keep us posted on the outcome.
 
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