If your Goodman AC is running but not cooling, the two most likely culprits are a failed run capacitor or low refrigerant. Both are common on Goodman equipment, and both need a technician to fix correctly. Here’s what we actually see on these units and how to tell which problem you have.
Why Goodman Units Fail Capacitors More Often
Goodman is probably the most common AC brand in Bay Area rental properties and entry-level installs. The equipment is functional and affordable, but the run capacitors tend to fail earlier than on some other brands, particularly when units sit in direct sun or in tight mechanical closets where heat builds up.
The run capacitor is a cylindrical component inside the outdoor condenser. It stores and releases electrical energy to keep the compressor and fan motor running through each cooling cycle. When it weakens or fails, one of a few things happens: the fan runs but the compressor doesn’t start, the compressor starts but trips the breaker, or the unit runs but struggles to cool at all.
Signs that point to a capacitor:
- You can hear the outdoor unit humming but the fan isn’t spinning
- The compressor starts, runs briefly, then shuts off
- The unit runs for a while but takes much longer than usual to cool the house A bulging or leaking capacitor is visible to the eye once a tech opens the panel. We check the microfarad rating with a meter. A weak capacitor that tests below spec is just as likely to cause problems as a completely dead one, and it’s often the ones that read “a little low” that cause the most confusion because the unit technically runs but poorly.
Capacitors are a straightforward repair. Part cost is low, and the job usually takes under an hour. If that’s all it is, you’re back to cool air the same visit.
Low Refrigerant: What It Actually Looks Like
If the capacitor checks out, the next most likely cause on a Goodman that’s not cooling is low refrigerant. A properly installed system shouldn’t lose refrigerant over time, so if the charge is low, there’s a leak somewhere.
Signs that lean toward refrigerant:
- The outdoor unit runs, the fan runs, but the air coming from vents is only slightly cool, not cold
- You see ice forming on the refrigerant line going into the indoor unit
- The larger insulated copper pipe (suction line) on the outdoor unit is not cold to the touch when the system has been running
- The system runs for long cycles without ever reaching setpoint
A tech will put gauges on the service ports to check suction and head pressure. Low suction pressure is a clear refrigerant indicator. We also check superheat and subcooling, which tell you more about what’s actually happening in the refrigerant circuit than the raw pressures alone.
Finding the leak is the part that takes time. Goodman has a known history of evaporator coil leaks, and that’s often where we look first. Schrader valve cores on the service ports are an easy fix if that’s the culprit. An electronic leak detector and UV dye find most leaks, though coil leaks sometimes require pressurizing the system with nitrogen to locate.
Topping off refrigerant without fixing the leak is a short-term answer. It’ll cool again for a season, sometimes less, and the refrigerant will continue to bleed out. A responsible tech won’t just add gas and walk away.
What You Can Check Yourself
Before calling anyone, check these:
The filter. A clogged filter restricts airflow and can cause the evaporator coil to ice over, which looks exactly like a refrigerant problem. Pull the filter and look at it. If it’s gray and solid, that’s your first step.
The breaker. The outdoor condenser is usually on its own breaker. If it’s tripped, reset it once. If it trips again immediately, stop and call a tech. Don’t reset it multiple times.
The thermostat settings and batteries. Obvious, but worth confirming the thermostat is set to COOL and the setpoint is below the current room temperature.
Airflow at the registers. Walk through and make sure all supply registers are open. Closing too many registers creates static pressure problems that can cause issues.
That’s about the extent of what’s safe to do yourself. The actual diagnostics, refrigerant handling, and electrical work inside the condenser panel are not DIY territory.
When to Call a Tech
Call sooner rather than later if you notice ice forming on any part of the system. Running a system with a frozen coil can damage the compressor, which is an expensive fix. Shut the system off and run just the fan to melt the ice, then call.
Same if you hear a grinding or screeching sound from the outdoor unit. That’s usually a bearing issue in the fan motor or compressor, and running it further makes it worse.
For a straightforward “running but not cooling” situation on a Goodman, we typically diagnose the problem on the first visit. Capacitor swaps are almost always same-visit repairs. Refrigerant work depends on whether you need a leak search and repair or just a recharge, but we’ll tell you what we found and what it’ll cost before we do anything.
If you’re in the Tri-Valley or East Bay and your Goodman unit isn’t keeping up, call us or book online at adriumservice.com. We’ll diagnose it on the first visit and tell you exactly what it needs before touching anything.