The hours after Milton, and the air conditioner that wouldn't start on the generator

6:00 a.m., the morning after

Milton came through overnight. In Bunnell the Haw Creek flooding has set a record and more than nine inches of rain have fallen. In Palm Coast the power is out across most sections. By six, generators are running in driveways from the Mondex to Palm Harbor.

6:30 a.m. Picture a homeowner in the R Section rolling out the portable generator bought after Ian, running the cords, plugging in the refrigerator and some fans. Everything hums.

7:15 a.m. The house is already muggy. He flips the air conditioner on at the thermostat, having had an electrician add an inlet and transfer switch last spring. The air handler blower starts. The outdoor unit clicks, groans for half a second, and the generator’s breaker trips. Everything goes dark.

7:20 a.m. He resets, tries again, same result. He tries with the refrigerator unplugged. Same result.

9:00 a.m. He calls us, and in a week like that he is far from the only one.

What he has is a generator that can run the air conditioner but can’t start it. That’s a specific, fixable problem, and it’s the subject of this guide.

The starting-amps problem

A compressor is a motor under load from the instant it starts, and for a fraction of a second it draws several times its running current to get moving. The data plate lists this as LRA, locked rotor amps, and on a typical 3-ton Palm Coast system it’s far above the running figure. A generator sized for the running watts of the house sees that spike as a short circuit and trips.

Three ways through it:

Approach	What it does	Trade-off
Bigger generator	Enough surge capacity to absorb the start	Cost, fuel, noise; often oversized for everything else
Soft-start kit on the condenser	Ramps the compressor up over a second or two, cutting the surge to a fraction	Modest cost, one visit; must be matched to the compressor
Variable-speed equipment	Inverter compressors start gently by design	Only applies when replacing the system

For most existing systems in this county, the soft-start kit is the answer. It’s a module installed in the condenser’s control compartment that limits inrush current, and it typically brings the starting draw down into a range a mid-size portable or a standard standby generator can handle.

Sizing the generator, in words

Add up what you want to run at once: refrigerator, some lights, a few fans, the well pump if you’re on a well in the west county, the air handler blower, and the condenser’s running draw. Then make sure the generator’s surge rating covers the condenser’s start with the soft-start installed, or its LRA without. A standby unit sized for the whole house handles this by design. A portable sized for the essentials usually needs the soft-start to add the air conditioner to the list.

Two things people forget: heat strips and the well pump. Electric heat strips in the air handler draw enormous current and should be locked out when running on a generator; in a Florida storm season you don’t need them anyway. A well pump’s start surge is a second compressor-like load and should never coincide with the AC’s.

Call 866-266-5709

The transfer switch is not optional

A central air conditioner is hard-wired on its own 240-volt circuit. Feeding it from a generator requires a transfer switch or a generator inlet with an interlock, installed by a licensed electrician, so that the house is disconnected from the FPL line while the generator runs. Back-feeding through a dryer outlet or a jury-rigged cord energizes the utility line outside the house and can kill a lineman working to restore power. It also tends to destroy the generator when FPL comes back.

Our part is the HVAC side: making sure the system can start and run on the available capacity, installing the soft-start, confirming the heat strips can’t engage, and checking the equipment after days on generator power. The transfer switch is the electrician’s part. We’ll coordinate with yours.

Running the AC on a generator, step by step

1. Start the generator and let it run a minute to stabilize.
2. Bring on the essentials: refrigerator, freezer, a few lights, fans.
3. Set the thermostat two degrees above your normal setting to shorten run time.
4. Turn the air conditioner on. Listen for a smooth start; a hard grunt means the soft-start isn’t doing its job or isn’t there.
5. Don’t run the heat strips, the oven or the well pump at the same time as a compressor start.
6. Shut the air conditioner off before refueling or stopping the generator, and let it sit a few minutes before restarting.
7. When FPL returns, shut the generator down, transfer back, and wait fifteen minutes of stable power before restarting the system.

After the generator week

Generator power is rarely as clean as utility power. Voltage sags during starts and surges when loads drop, and a week of that is hard on capacitors, control boards and the compressor. After an extended outage we recommend a check of the electrical components and a look at the surge protector at the disconnect, which may have done its job and need replacement. In Bunnell and along Haw Creek, that check includes the flood inspection: a unit that stood in water and then ran on a generator for a week has had a hard month.

Getting ready before the next one

Soft-start installed. Heat strips locked out on the generator circuit. Surge protector at the disconnect. A transfer switch rated for the condenser’s circuit. A note on the generator with the order of operations. And the pre-storm checklist from the hurricane guide done in June rather than the night the cone shifts. [[CONFIRM WITH JERRY: whether Cook’s stocks soft-start kits for the common compressor sizes year-round or orders per job]]