If you’ve owned an RV for any length of time, then you understand how finicky their air conditioners can be. We’ve all been there where it’s a million degrees outside, and your RV AC refuses to run consistently. Instead, it cycles on and off even though there doesn’t seem to be anything physically wrong with it.
The main reasons that RV air conditioners cycle on and off is because of a wiring issue, power supply issue, thermostat issue, faulty control board, dirty air filter, or frozen evaporator coils. Most of the time it is a dirty air filter, frozen coils, or a thermostat issue causing the issue.
Regardless of why your RV AC is cycling on and off, it’s a nuisance and can create a hot and unsafe RV. Therefore, you’ll have to put on your troubleshooting hat and determine the issue. This article will walk you through the possible reasons for short cycling and how to fix them.
Common Reasons That RV Air Conditioners Turn On and Off
Without further ado, let’s dig into the possible reasons for short-cycling air conditioners. We’ll list the reasons in the order that’s easiest to check, going from the least invasive to the most invasive.
A Dirty Air Filter
Aside from a faulty thermostat or wiring problems, a dirty air filter is the most likely culprit. It’s also the easiest component to examine for issues. The air filter on your air conditioner is responsible for catching dirt, pollen, and other particles as air cycles through your AC to get supercooled. The filter aims to catch these particles before they pass into your living space, thereby providing cleaner air.
However, the more dirt and crud your air filter catches, the dirtier and more clogged it becomes. Eventually, if the filter is dirty enough, it will block the airflow and cause cycling issues with your air conditioner. The AC will cycle on and off because it’s getting overworked and can’t produce enough air.
How to Check and Fix
To check your air filter for dirt, turn the air conditioner off so it can’t cycle on while the filter is removed. If you see that the filter is dirty, you’ll have to thoroughly clean and dry it before reinserting it into your air conditioner and turning it on. However, you’ll have to move on to the next possible problem if it isn’t dirty.
Your thermostat is the next thing to check. If you have a newer camper, you may have a digital thermostat that uses batteries. If the batteries are dead or dying, the reduced power can cause your AC to cycle on and off.
If you have an older camper, you’ll likely have a non-digital thermostat that uses a fuse instead of batteries. However, this fuse can loosen inside the thermostat, causing intermittent bursts of power. When this happens, the AC will cycle on and off as the fuse makes and breaks contact with its terminals.
How to Check and Fix
To ensure that batteries or a fuse aren’t the issue, you can install new batteries and check the fuse to ensure it’s tight. You’ll have to pull the face of the thermostat off the wall to do this, so you should first turn off the air conditioner.
Frozen Evaporator Coils
You can optionally check the coils before checking the thermostat because frozen coils are an obvious problem that’s easy to see. The only catch is that you’ll have to climb on top of your RV and remove the protective shroud around your air conditioner. Once you do that, however, you should easily be able to tell if there’s ice on top of the AC coils. Ice forms when a refrigerant line leaks or if it’s too hot outside and your air conditioner can’t keep up.
If you don’t see ice on your evaporator coils, but you do see dirt and grime, the coils may be clogged. Dirty evaporator coils have the same cause and effect as a dirty air filter. Air constantly passes over the coils, so dirt gets trapped and left behind. Eventually, it will block airflow and cause your AC to cycle on and off because it’s getting overworked.
How to Check and Fix
As with your air filter, you’ll have to clean the evaporator coils to get your AC working again. If there’s ice on your coils, turn the AC off until the ice melts. You can then start it back up and see if the problem repeats. If it does, you should contact an HVAC technician to fix the issue.
Faulty Thermostat or Electrical Wires
Your air conditioner has two sets of wires connected to it – the power wires and the thermostat wires. Typically, two or three power wires connect the AC to a circuit breaker, and between two and five, connect the AC to the thermostat. Any of these wires can get frayed or damaged, resulting in short cycling.
It’s also possible that one of the wires isn’t tightly connected and is intermittently touching and releasing the power terminal. When this happens, the AC will turn on when the wire makes contact but turn off when the connection loosens.
How to Check and Fix
Here’s how to check for wiring issues.
- Turn the AC off and flip the circuit breaker to ensure that power is completely cut off to the air conditioner.
- Check the AC wires for visible damage or a loose connection at both the AC and the circuit breaker.
- Check the thermostat wires for damage or a loose connection at both the AC and the thermostat.
- Tighten loose wires, or repair damaged ones. Depending on the damage, you may have to run an entirely new set of wires.
Busted Control Board
Finally, you should contact a service professional if your AC is cycling on and off because of a faulty control board. There are a lot of different components on control boards, and they’re very difficult to examine and troubleshoot. Only an experienced HVAC pro with the proper tools and knowledge should mess with control boards. Otherwise, you could cause a bigger issue.
How to Clean Your Air Filter and Condenser Coils
Since the only way to rectify dirty air filters or condenser coils is to clean them, let’s examine precisely how to do that.
How to Clean an AC Air Filter
- Turn off your air conditioner.
- Remove the air filter, which is located on the bottom side of the air conditioner inside the RV. There should be two filters.
- Run warm water over the filters until the dirt has been removed.
- To kill bacteria, you should also periodically soak the filters in vinegar and warm water.
- Set the filter out to dry inside your RV.
- Reinstall the filters when they’re dried, and turn the AC back on.
- Running the AC with wet filters could cause mold and unclean air.
How to Clean Condenser Coils
- Turn off the air conditioner.
- Locate the condenser coils on the outside of the air conditioner on top of your camper.
- Remove the outer shroud of the air conditioner to access the coils below.
- Take towels or blankets to cover any holes where you can see through the air conditioner and into your RV.
- Use a garden hose to gently spray the coils with water until they’re clean.
- Before spraying, you can also try cleaning the coil with a vacuum.
Frequently Asked Questions
Why does my air conditioner keep cycling on and off?
The main reason that an air conditioner cycles on and off is because of a wiring or thermostat issue. However, it could also be due to a dirty air filter and dirty or frozen evaporator coils.
How do I stop my AC from short cycling?
To keep your AC from short cycling, you’ll have to determine what’s causing the issue and repair it.
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