AC requirements for HVAC

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  #1  
Old 06-20-06, 06:04 AM
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AC requirements for HVAC

HI there,

Having an Air conditioning system only installed.

For outside condenser, name plate states 21.9 Min Cir Amp.
So after much reading, seems I should be OK with 10/2?

Also there is no Min breaker rating, only a Max breaker rating..which is 35 AMP. Having a hard time finding one, is it ok to use a 30 AMP?

For inside air handler, which is also 220vac, nameplate is 5amps..is it ok to do the following.

1. Install a 15 amp Double Pole breaker
2. Run a 14/3 to unit.
3. Pass both hots through a dpst switch, one hot feeds an outlet (utilize neutral in 14/3 for 110) which is in same 4 square, then both pass both hots through box and into unit where they are connect to the leads for the air handler.

I need the disconnect and also the outlet for the condensate pump, have been reading that its ok to put this on the load side of switch. That way all HVAC components are off when service switch is off.

Does this sound correct?

Thanks!
 
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  #2  
Old 06-20-06, 02:14 PM
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Install a 30 amp. You won't find a 35 amp.

1. yes
2. Since you need 120 for condensate pump yes 14/3.
 
  #3  
Old 06-20-06, 03:02 PM
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Thanks Joed,

On #1 I managed to find a 35amp breaker so clear on that one.

on #2 - There's no issue or impact of using one of the hots for the outlet before it connects to the 220vAC?
Just want to make sure....one EC I talked with said that I should be running 2 circuits over to the air handler, 1 for the 220and another for the 120vac. (condensate pump)
In that case i would end up with two switches....not my idea situation but I'll do whatever is the correct way of doing it.

Also in these cases is the low voltage power transformer for the controls also meant to be switched off as part of the disconnect?
 
  #4  
Old 06-21-06, 08:05 PM
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NEC code will not allow you to tap one leg off of 220 and use ground as a neutral to power your 120v outlet for the condensate pump, you will have to run a seperate circuit or just use a nearby 115v outlet for the pump. The pump uses minimal amps and wont be an issue on a nearby circuit.
Yes whenever the circuit for the airhandler is turned off that will and is supposed to cut power to the transformer therefore dropping out the complete low voltage circuit.
Also just to be clear, the air conditioner will need to have a disconnect box mounted within close reach outside for servicability. The air handler will also need a disconnect box within range unless there is a breaker either built into the airhandler or within sight of it.
 
  #5  
Old 06-21-06, 08:11 PM
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Originally Posted by nomore9to5
NEC code will not allow you to tap one leg off of 220 and use ground as a neutral to power your 120v outlet for the condensate pump, you will have to run a seperate circuit or just use a nearby 115v outlet for the pump. The pump uses minimal amps and wont be an issue on a nearby circuit.
Yes whenever the circuit for the airhandler is turned off that will and is supposed to cut power to the transformer therefore dropping out the complete low voltage circuit.
Also just to be clear, the air conditioner will need to have a disconnect box mounted within close reach outside for servicability. The air handler will also need a disconnect box within range unless there is a breaker either built into the airhandler or within sight of it.

Thank you for pointing this out. We can all make anything work, there is a right and wrong way. Even the wrong (not to code) way can be done safely, this is not one of those cases.
 
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Old 06-22-06, 03:13 AM
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Originally Posted by nomore9to5
NEC code will not allow you to tap one leg off of 220 and use ground as a neutral to power your 120v outlet for the condensate pump, you will have to run a seperate circuit or just use a nearby 115v outlet for the pump. The pump uses minimal amps and wont be an issue on a nearby circuit.
No one is saying that at all. Read the OP again. He is saying to run a 14/3 instead of a 14/2 for the 240v circuit. This way he has his two hots and a neutral.
It is perfectly legal and an easy way to tackle this installation.
 
  #7  
Old 06-22-06, 06:55 AM
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Thanks Speedy..that was it exactly.

I had no plans to utilize the ground for anything other than ground which is why I was pulling a neutral.

In the end I was unsure, so I ran a cirucuit for the condendate pump/service outlet 110volt , and a dedicated 220 volt circuit for the air handler/low voltage transformer.
 
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