AC condenser keeps freezing uo

Bell Brothers has been Sacramento’s go-to HVAC company since 1991. Over the years we’ve spread our reach north to Yuba City, west to Fairfield, south to Stockton, and east to Placerville. Now, we’re extending our HVAC service to Fresno. We’ve only been down there a few short months but we’re already getting great customer feedback. We also have a great story to share with our readers!

If you think it’s never iced over in Fresno, you’d be wrong. While the average temp in winter isn’t close to freezing, we saw some serious ice this month. That’s right, ice, in Fresno, in July! How did this happen? Well, it all has to do with the outdoor air-conditioning unit — that metal box that sits outside the home with the fan.

Air Conditioner Basics

Known as the condenser, the outdoor unit’s job is to take refrigerant gas from the inside of the system, pressurize the gas with a compressor, and cool it with fins. As the gas cools it “condenses” into a liquid. The condenser then sends the cold, liquid refrigerant back into the house. Inside, a fan blows air over coils full of the liquid refrigerant. This cools the air, which is then blown through the home through ducts. Meanwhile, the liquid refrigerant warms up and turns back into a gas! So it gets sent back out again to the condenser, pressurized, cooled, and so on!

This is a simplification of a complicated process, and a lot can happen. One symptom of things going wrong is ice forming on the outside of the condenser. That’s what happened to our client in Fresno, and he was pretty confused! When this occurs, it’s usually because of a few things.

Common Causes of a Frozen AC Condenser

If air filters are dirty inside the house, then air won’t end up getting to the liquid refrigerant. When that happens the liquid refrigerant doesn’t warm up, which means it goes back into the condenser cold. That lowers the temperature of the condenser’s cooling fins enough for them to form ice.

Similarly, a system that’s low on refrigerant will cause the same problem That’s because there’s less refrigerant to cool, so it all cools faster (just like small ice cubes freeze faster than a water bottle would). As we know, when it gets colder faster than it should, the condenser gets very cold and will ice over. Even if a system has enough refrigerant, there are plenty of relays and valves that can fail. If one of them does, the effect is the same as if the refrigerant was low, and you end up with a frozen condenser.

Finally, if the temperature outside drops below 65º Fahrenheit, the condenser is colder than it should be. Run it then and you’ll have the same problem.

Finding the Problem

We were pretty sure that the temperature hadn’t dropped recently, more’s the pity, and we also knew that this client had clean air filters and no other air blockages. We’d never worked on his condenser before, but we suspected that a low refrigerant level was to blame. Sure enough, the level was low. This is where calling the pros really came in handy. It would have been easy for us to just top off the refrigerant and call it a day. But recharging a system is not a walk in the park. Do it wrong, and you’ll harm the system. Furthermore, when a system is low on refrigerant, there’s usually a leak.

That’s what we tested for, and it didn’t take long to find — or to fix! Once we were satisfied, we flushed out his old refrigerant and recharged the system with brand new stuff. We de-iced the condenser (didn’t take long in this heat!) and his system was good to go!

How about yours? If you live in the Fresno area and want no-nonsense service backed by our “No Surprises” guarantee, you should get in touch. We at Bell Brothers treat our clients like family, and we would love to hear from you.