Breakers for air conditioner?

[Charles Smith]

Inspected house with two roof top Rheem Rheem AC/Heat Combo Model RRKA-A030JK08E (heat & AC) combo units.

Unit 1 has a 35 AMP (240 VAC 120/120) tied or ganged breaker.

Unit has two separate breakers that are not tied or ganged
15 Amp breaker on Leg 1 (120) and a second 15 Amp breaker on Leg 2 (120).

I believe the Rheem spec for this model is 20 Amp minimum and 30 amp maximum for circuit protection.

Besides being under the minimum (15 amp) size breakers should they be tied.

Charles in Santa Fe

[Matthew Barnicle]

Yes..

[Richard Moore]

Inspected house with two roof top Rheem Rheem AC/Heat Combo Model RRKA-A030JK08E (heat & AC) combo units.

Unit 1 has a 35 AMP (240 VAC 120/120) tied or ganged breaker.

Unit has two separate breakers that are not tied or ganged
15 Amp breaker on Leg 1 (120) and a second 15 Amp breaker on Leg 2 (120).

I believe the Rheem spec for this model is 20 Amp minimum and 30 amp maximum for circuit protection.

Besides being under the minimum (15 amp) size breakers should they be tied.

Charles in Santa Fe


Actually, it's 30-amp minimum, 35-amp-maximum. (see the attached chart I took from the spec sheet at http://www.winmech.com/r11_834_rev2_rrka1to5_rrma1to4_rrna2to3.pdf )

So...unit 1 breaker looks just fine. Unit 2, assuming it's exactly the same model, should have a similar 30 to 35-amp breaker...and with the handle tie (any 240-volt circuit is a hazard without the handle tie). Even though the RLA (rated load amps) for the unit is only 15-amps, I'm really surprised that it can actually start up and function without the surge tripping the 15-amp breakers.

[John Steinke]

Why say "I believe the specs ...?" The units ought to have nameplates. Indeed, the NEC requires nameplates.

For the past several years, it's been even easier, as the nameplates have been required to state the minimum circuit ampacity, the minimum breaker/fuse, and the maximum breaker/fuse. The nameplate has always been required to state the voltage.

Your answers are right on the nameplate.

One detail to watch ... on units that have separate condensers and evaporators, it is common for each part to have its' own separate power. That is, one circuit will power the condenser, while another will power the evaporator.

The condenser .. the part sitting out back, under the bushes (:D) is the condenser. These are usually 240v. If so, they need a two pole breaker, and the handles need to be tied together.
The evaporator .... the part that's often inside the furnace ducting ... may have nothing but a fan and a thermostat to power. This is usually 120 ... and often fed from the furnace circuit.