Wiring hot water heater pump to 240 circuit

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  #1  
Old 07-14-14, 06:40 PM
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Wiring hot water heater pump to 240 circuit

I have a 0.5 amp recirculating hot water heater pump that I wish to wire to the hot water heater timer (240v). The water heater circuit is 30 amp, 10-2 wire (2 hot + ground). Water heater + pump is less than 24 amp so no problems there. The pump is 120v and currently plugged into a receptacle on another circuit. I would like to put it on the circuit with the water heater timer so that the pump is only running when the water heater is on.

The question is how to properly wire the pump. Can I use one of the hot wires from the water heater circuit to get the 120v? If so, the next question is how to get the common wire for the pump. Can I use a common from another circuit? I am guessing the answer to both of these is that it is probably not advisable.

If that is the case, can I change out the wire to 10-3 and then use one of the hot wires for the load and the white wire for the common to wire the pump? Any help would be appreciated.
 
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Old 07-14-14, 07:00 PM
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Welcome to the forums! You won't be able to connect the pump to the water heater circuit. One is 240 volts without a neutral and the other is 120 volts requiring a neutral. How is your timer wired? is it an external timer from the water heater? It is possible for you to run 10-3 w-g to the timer and achieve power, but it must be protected at a much lower rate (15 amps) than the water heater. Take a picture of the inside of your timer showing the wiring. There may be a way to use it as a switch to control both, but we'll need more information about it first. http://www.doityourself.com/forum/el...your-post.html
 
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Old 07-14-14, 07:08 PM
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Like Larry said, a general purpose receptacle cannot be on a circuit greater than 20 amps and the WH circuit does not have the needed neutral.
 
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Old 07-14-14, 08:05 PM
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A relay with a 240 volt coil may be a solution or if timer is for circ pump only a different timer.
 
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Old 07-14-14, 09:21 PM
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The wiring diagram can be found here: http://waterheatertimer.org/images/W...g-2011-500.jpg
The timer is external from the water heater.
 
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Old 07-14-14, 09:41 PM
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A NO contactor (relay) with a 240 volt coil would be the simplest solution. Mount the contactor and a simplex 15 amp receptacle in a 4X4 box size permitting. Contactor should have a horsepower rating equal to or greater than the pump. You only need single pole but it will probably be 2 poles or more.
 
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Old 07-14-14, 10:08 PM
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Thanks for the reply. I have never used a relay before. Is there one you would suggest that would do the job and is there somewhere I could find a wiring diagram? Thanks!
 
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Old 07-14-14, 11:40 PM
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The pros can best suggest one. Here is the wiring.

Name:  WH40-wiring-2011-500.jpg
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Last edited by ray2047; 07-14-14 at 11:55 PM.
  #9  
Old 07-15-14, 08:52 AM
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What schedule are you planning for the timer? If the intent of the pump is to keep hot water available through a loop that passes by all bathrooms and kitchen it isn't, in my opinion, a good idea to restrict the pump's operation by the water heater's timer. I would want a separate pump timer that would allow the pump to continue to operate during those periods when you rely on the stored hot water to furnish your needs.
 
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Old 07-15-14, 10:40 AM
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Joe, that is a good point. The whole goal of this was to have all of the controls in one place so that whenever we leave for a few days, we can turn the whole system off very easily. I think I will just get a separate timer for the pump and wire it such that everything can be easily turned on/off. And it will probably end up being cheaper...

Thanks to all for the input.
 
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Old 07-15-14, 07:47 PM
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Joe, that is a good point. The whole goal of this was to have all of the controls in one place so that whenever we leave for a few days, we can turn the whole system off very easily.
If that is the case I think I'd install a dedicated 20 amp circuit for the pump and new pump timer so I could just turn off the two breakers when I was planning to leave town for a few days. If you want to get more elaborate you could install the new dedicated pump and pump timer circuit and break both the pump circuit and water heater circuit with a 3 pole non-fusible disconnect giving you only one handle to throw. Personally, I'd forget the 3 pole disconnect and just turn off the breakers. Of course, you'll have to reset both timers when you return home.
 
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