Spit AC (or Ductless)

[tom baker]

A split AC or ductless system is one that has an outside condenser unit with an indoor unit with the cooling coils and a fan. There is a disconnect for the outside unit and the inside unit is fed from that disconnect. There is typically a disconnect for the inside unit next to it.

There is a proposal in Washington State to not require the disconnect for the inside unit as its fed from the outside unit, which is lockable.

The rules for HVAC disconnects are different that those for motors.
"440.14 Location.
Disconnecting means shall be located within sight from and readily accessible from the air-conditioning or refrigerating equipment."

The group who wants no disconnect for the indoor unit has overlooked this slight difference.

For a motor the disconnect must only be within sight.

You could have the outdoor unit located on the roof, accessible via a ladder from grade. With out a disconnect located next to the indoor unit, you may be tempted to work on the indoor unit hot rather than going back outside and up the ladder.

There is also a proposal to call this equipment a single machine under 440.14.

Comments? Could the disconnect for the indoor unit be eliminated and not compromise worker safety?

 

[Mgraw]

My opinion, as someone who does both HVAC and electrical, disconnects are needed on the inside units. I have worked on these units where it was a pain in the neck to go back and forth to shut the units off. (disconnects on the inside units is fairly new here) Many times I don't and just work on them hot. Some of these units have multiple indoor units on one outdoor unit. To work on one indoor unit you would need to shut the whole system off. I do not see them as any different than a central split system.

 

[Buck Parrish]

FWIW Some HVAC guys wire the fan with a controll wire in thier 18 gauge thermostat wire. When I questioned it. They said some of the indoor units have a fan that works off 36 volts.
So the only thing going to the indoor unit is a thermostat wire.