Air handler unit

S

Stubby

Member
Location
Climax
Occupation
Electrical
I have two air handler units that have no heat strips just a blower motor only. The inspector said I had to separate both air handlers I could not put them on one circuit breaker max amps are 5 amps per ahu. I do have a disconnect at the air handler for both of them
 
He could be thinking of 422.12 This requires central heating equipment to have an individual branch circuit. However, there is an exception:
Exception No. 1: Auxiliary equipment, such as a pump, valve, humidifier, or electrostatic air cleaner directly associated with the heating equipment,
shall be permitted to be connected to the same branch circuit.

This doesn't explicitly list a 2nd air handler, but I think the intent covers it. The code wants the HVAC system on its own circuit without other unrelated things or general purpose outlets.
 
infinity said:
IMO no. Two air handler units are part of two separate systems. Do you think that one unit is auxiliary equipment to the other?
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That sounds more like exception 1... In '17 exception 2 addresses permanently installed units
 
augie47 said:
Would exception #2 (17 nec) not allow it ?
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I'm thinking that they mean the air handler and outdoor compressor as "permanently connected air conditioning equipment". Not two separate systems.

Like I said above, is there a label that shows the electrical requirements and would prohibit a shared circuit? I'm trying to relate these to unit heaters which can share a circuit.

-Hal
 
augie47 said:
That sounds more like exception 1... In '17 exception 2 addresses permanently installed units
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I don't see the OP's question referring to permanently connected AC. what am I missing? 2017 NEC:
422.12 Central Heating Equipment. Central heating equipment other than fixed electric space-heating equipment shall be supplied by an individual branch circuit.
Exception No. 1: Auxiliary equipment, such as a pump, valve, humidifier, or electrostatic air cleaner directly associated with the heating equipment, shall be permitted to be connected to the same branch circuit.
Exception No. 2: Permanently connected air-conditioning equipment shall be permitted to be connected to the same branch circuit.
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infinity said:
Yes but why would a single system have two air handlers as mentioned in the OP? Wouldn't two units be used for two separate systems?
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No juts wired a Samsung ductled split system with 2 AHU’s no heat kits and one outdoor unit I could’ve put both indoor units on the same circuit and used exception 2 but I separated them
 
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infinity said:
Yes but why would a single system have two air handlers as mentioned in the OP? Wouldn't two units be used for two separate systems?
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I've seen it once, at the school my younger son previously attended. My older son does HVAC and we swapped out two furnace units that were sitting under a single A-coil because the space didn't have the dimensions needed by a single unit.

Granted, these were gas furnaces but in some situations could have easily been air handlers.

It was two furnaces, one thermostat, one a coil, one rooftop AC unit. We were replacing an older setup which had contactors on the wall for each of the poles on the thermostat, so that the controls for each furnace unit were powered by that unit but having single power for the thermostat

My son said in modern applications it would simply use two communicating furnaces
 
suemarkp said:
He could be thinking of 422.12 This requires central heating equipment to have an individual branch circuit.
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If there is no heat installed how can it be central heating equipment, other than if they are heat pumps.

If they work together somehow how do we define it?

Worst case make the local disconnects be fused safety switch or circuit breaker units and then you have a feeder and individual branch circuits tapped off of it.
 
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