When you have a split system HVAC unit, where the air handler mounts on a wall in the room (sometimes over the door.) and the compressor is outside. We know that the compressor needs a disconnect, what about the air handler? Do they have a built in disconnect switch inside of the unit? What if there isn't one, do you need one? What if the circuit breaker is lockable, would that count as a disconnect?
Yes the AH would need a disconnect.
Most of these that I have done have the switch built in (Sanyo).Both 120 and 240 V models.
The breaker would still need to be 50' and With in site.
The air handler in mine is low voltage, wired with thermostat wire. I assume the disconnect is the plug.
I think I have bigger fans in my PC case. It is about an amp at 24v as I recall. The condenser is 120v listed for a 15a circuit. I put it on the service outlet for my real AC.
My electric water heater on its own 240V 30A circuit, rated 4500W, does not have any disconnect other than the breaker itself. It is hardwired without a plug. Does it need any more of a disconnect? I don't see how this would be any different than the air handler part of the AC, as long as it is at least on its own circuit.
If your referring to a mini-split AC system, all of the systems I have seen for probably the last 15-years get power for the indoor evaporator blower and controls from the terminal board in the outdoor condenser.
When you pull the disconnect for the outdoor unit, you also kill power to the indoor unit. I would say that unless you see a requirement for a separate disconnecting means for the indoor unit in the manufactures listed instructions for that particular equipment, you shouldn't need one.
Electric Water Heaters come under Appliances (422.13).Article 422
Cannot have a Plug for a Disconnect unless its portable (422.1 & 422.16) & does require a Disconnect either Within Sight OR capable of being locked (422.30 & 422.31).
Motors AHU's ect come under Article 430.
Start with 430.101 & 430.102 (A) & 430.102(B)
They do require disconnect switches per theses sections.
430.109 Types of Disconnect switches Approved for use as stated.
Except under the exceptions as noted.
You want to look at Article 440, Air Conditioning equipment. Specifically, 440.14.
The disconnect - which CAN be a plug - has to be within sight of the equipment. Now, some might quibble, but to me, this means that the disconnect for the equipment you're working on has to be within sight of that equipment. In other words, if the system has components in more than one location, each location needs another disconnect.
BTW, a point of vocabulary: the part we are discussing is called the 'evaporator.' An 'air handler' is another piece of gear completely. The part outside is called the 'condenser,' and contains the compressor.
430.109 does list a Cord & Plug as a approved disconnect . I stated see 430.109 .
440.13 Cord -Connected Equipment
440.12(D) Disconnecting Means Refers you to 440.12
440.14 Location (within sight ) Same as 430.
There is a Exception #1 But for Industral process.
Exception # 2 Might interest you .
440.3 A & B Says 430 applys EXCEPT as modified by 440.
These things are close to being 725 class II. I am still looking for the spec on the air handler. It is trivial tho.
Usually the units i have seen are powered separately.
Disconnect is needed for both.
In the type of system I am talking about the air handler has it's own separate feed. It does not connect to the outside condenser except for the low voltage control wiring. The manufactures instructions do not show a disconnect either. Now if this was a regular air handler in the attic, a disconnect would be required.
How about a breaker lock? Would that make it a "Lockable" disconnect?
Also there is no plug and cord for the unit I refer to.
P.S.
I just saw leland's comment on the 2nd page.
I agree with leland, that a disconnect would be needed for both.
OK I was confused by the "hang on the wall" part and assumed a mini/split. In a regular AC unit with separate line voltage feed I agree you need a disco. In fact, these may have a pretty hefty toaster wire heat strip in them. My condenser is something like 17a, the air handler is closer to 50 with the heat on. (10 kva heat), on a 60a circuit.
Since these usually get installed in the attic or in a closet there is always the argument about working clearance around the disco. For some reason they usually let that slide but get concerned about the one on the condenser. Never made sense to me.
Greg,
There are several types of split systems. This air handler is 220 volt 15 amp. separate feed and has no heating coil and has no disconnect switch built in to it. It acts just like a typical AH that would be in an attic, but it is mounted on the wall. This one happens to be in my house:
http://www.residential.carrier.com/interactive/ductfree.htmlOr something similar to it. Except there is no heating coils. Would a lockable breaker count for the disconnect?
Harold, Are you a qualified person?
If so, I read that the breaker will do.
440.14 exception 1:
A) Or, Could this unit be termed a 'controller'?
A) 430.102(B)(2) Exception.
It's standard procedure around here to to install a receptacle for the AH. 9 times out of ten it's a 120V unit mounted in the attic. The HVAC guy puts a pigtail on his unit and it can be tested (or run for temp heat) with an extension cord if he gets his job done before I get there.
Another benefit is that the HO can also run it from an extension cord for troubleshooting purposes or by portable genny in an outage.
Falls under the keep it simple rule as I see it.
Leland, that is the minisplit I was talking about. They have a low voltage air handler, fed from the condenser.
Harold is talking about an air handler with 240v 15a feed. I can't imagine why you need all that if there is no heat.
The blower is going to be a fractional HP motor.
If it is 1/8 or less then you can cite 430.81(A).
Talking about Harold's air handler, I still bet this air handler has a heat bay if it really has a 3.6kva (240a @ 15a)circuit requirement. That machine does need a disconnect within sight IMHO.
If you can see the breaker from the AHU, you don't need a disconnect. Otherwise, you need some form of disco, whether it's a plug or a $20 HVAC disco switch or what have you. This applies even if the unit has a built-in breaker.
If you can see the breaker from the AHU, you don't need a disconnect. Otherwise, you need some form of disco, whether it's a plug or a $20 HVAC disco switch or what have you. This applies even if the unit has a built-in breaker.
Even a built in breaker/switch?
That's a disco. No?
If not why?
Ah, 422.34 answers this. Yes, the built-in breaker counts as the disco, but only in one and two family homes. For apartments and commercial, there are other (easily met) restrictions.
I suppose we could go to the installation manual for the machine Harold referenced
http://www.docs.hvacpartners.com/idc/groups/public/documents/techlit/38h,q_40q-1si.pdfIt is a mini-split that feeds the air handler directly from the condenser but it does use 208/240 on the interconnection cable. My LG does this with low voltage.
The manual does not say anything about a disconnect at the air handler and the servicing instructions say you should turn off the outside disconnect when servicing the equipment. The fan is listed at 53w so it is less than 1/8HP
and it might fall under 430.81(A)
Would a disconnect, not called for in the installation instructions be a 110.3(B) violation?
This is in Harolds' home. He is a 'Qualified person.
I see some 'Devils advocating' here.
(I see your point)Thanks for pointing this out to me.
Greg,
Sorry for not getting back sooner. There have been several styles of air handlers (AHU)that I see. The one in particular is 240 volt, 15 amp feed. The motor is tiny and I doubt if it even pulls 1-2 amps. (I don't have the paper work in front of me) It is not powered from the outside unit and it is not in sight of any circuit breaker. My question would be is a "snap switch disconnect" be required along side of the AH on the wall or could a breaker lock be the "Disconnect" for this AH. As for "Devils Advocate", I will explain later.
The Carrier mini-split they are selling on that link you posted a while up thread is fed via the condenser. There is no separate feed to the air handler if the installation instructions are right.
The largest optional blower is 53w or about 0.22a.
The 15a @ 240 is the whole thing, condenser and all and it still doesn't use much of it. The compressor is 4.7a RLA and the condenser fan is 0.8a.
My 9kbtu LG will run on 120v 15a and the condenser is so quiet you barely know it is running standing right next to it.
Yes the AH would need a disconnect.
Most of these that I have done have the switch built in (Sanyo).Both 120 and 240 V models.
The breaker would still need to be 50' and With in site.
I'll stand by this.
You will be presented with a brown, a blue and a black along with the green/yellow ground. Which wires get "disconnected"?
You will get no guidance from the installation instructions since they don't call for a disconnect.
Would adding one be a 110.3(B) violation?
All of this wiring is way past where the line cord enters the machine (in the outside unit)
A hint on the top question. If you hooked this up with 14-3 wg Romex without reidentifying the white it would be a 200.6 violation
As a side note, do you require a disconnect for ceiling fans?
Greg,
The contractor gave me the paper work for this particular unit. It is a Carrier BNC/BNQ 024,030,036 Duct Free System ( Not sure which unit he is using) but the wiring diagram just shows 3 wires (1 Cable) to the inside unit. L1 (Brown) L2 (Blue) and Gray/yellow ground, then it shows it going to a Mains AC supply 208/230 VAC.
It will be mounted up high in a rec room above the door into the room. The wiring diagram doesn't show any on/off switch on the unit itself. There is a wireless remote control that goes with it in the room.
The full load amp says 0.6 amp. I don't even see a HP rating for this little motor. It is a single phase machine.
The installer says that he never installs a disconnect or snap switch for any AHU that he has installed. He thought that a breaker lock would satisfy the disconnect rule.
The feed (Breaker) will start at a sub panel in the basement, so the breaker will not be in sight of this unit. The Air Compressor will be outside under a deck and it will have it's own separate feed (Breaker) and a pull out AC disconnect.
Sorry if I am making this small job seem so difficult to figure out. I am just at a different opinion than a fellow colleague of mine. LOL That is why I wanted it on screen.
I was wrong
The installation book I referenced is for the QNC/QNQ
and it shows 4 wires that go back to the condenser.
I just looked at your unit and it does in fact have a line voltage connection.
http://www.docs.hvacpartners.com/id...2618916-D&HighlightType=PdfHighlightI was really surprised that this thing used line voltage at all. Most I see use 24v for the air handler.
So I guess that a 220 volt air handler without a switch would need a disconnect.