AC Compressor Low Pressure Too High: 2 Proven Solutions

AC compressor low pressure too high? But hey, don’t sweat it. There are ways to diagnose and fix this issue, and that’s what we’re going to walk you through.

AC Compressor Low Pressure Too High
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Understanding AC Pressure Readings

Now, in AC speak, ‘low pressure’ and ‘high pressure’ aren’t about blowing up balloons. They refer to different stages in the refrigeration cycle. The ‘low pressure’ side involves the evaporator and the suction line, where the refrigerant is in gas form.

The ‘high pressure’ side, on the other hand, includes the condenser and the liquid line where the refrigerant is in liquid form. Simple, right? Now imagine if the low-pressure side starts acting like it’s high-pressure—that’s the conundrum we’re dealing with.

Causes of AC Compressor Low Pressure Too High

Before we play detective, let’s look at the usual suspects behind your AC compressor’s low pressure going sky-high. Knowing what might be causing the problem is half the battle won, right?

Overcharged System

Imagine having too much of a good thing—it’s not so good anymore, is it? That’s what an overcharged AC system is like. When you fill it up with too much refrigerant, it can cause the low-pressure side to have higher pressure than it should. Just like overeating at your favorite restaurant, overcharging your AC can leave you in an uncomfortable situation.

Faulty Compressor

Remember how we talked about the compressor being the heart of the AC system? Well, when the heart isn’t pumping right, things can go haywire. A faulty compressor might not be able to handle the refrigerant correctly, leading to high low-pressure readings. It’s like a pump working double-time—it’s bound to create extra pressure.

Blocked Expansion Valve

Here’s another culprit—a blocked expansion valve. This little guy controls the amount of refrigerant going into your evaporator. Now, if it’s blocked, it can’t do its job well. The result? Yup, you guessed it—high-low-pressure readings. It’s like a traffic jam on a one-way street—everything backs up, causing pressure.

Dirty or Clogged Air Filter

Last on our list of usual suspects is a dirty or clogged air filter. If the filter’s blocked, your AC system has to work harder to draw in air. And more work can mean—you got it—more pressure. Think about trying to sip a thick shake through a narrow straw—it’s tough!

Diagnosing AC Compressor Low Pressure Too High

Now that we know our suspects, let’s pull out our detective hats and find the culprit behind those high-low-pressure readings. It’s a bit like solving a whodunit, but don’t worry, it’s not as daunting as it sounds.

Checking the Pressure Levels

Okay, it’s time to roll up those sleeves and get down to business. To verify your suspicion of ‘AC compressor low pressure too high’, you need to check the actual pressure levels in your AC system. This is where AC gauges become handy.

These two-part tools – the high-pressure gauge (red) and the low-pressure gauge (blue) – let you peer into the internal pressures of your AC system. Connect the AC gauges to the service ports on your AC unit – the low-pressure side to the larger port and the high-pressure side to the smaller one.

With the AC system running, note the readings. The exact pressure values can vary based on your system and the ambient temperature, but typically, the low-pressure side should read less than 100 psi. If it reads higher, well, you’ve got a case of high low-pressure.

Identifying Overcharging

An overcharged AC system is like a balloon filled with too much air – it’s ready to burst. When there’s too much refrigerant in your system, both low and high sides will show higher pressures. Plus, your AC might be unusually warm.

If your AC gauges show high pressure on both sides (low side over 100 psi and high side over 250 psi on a cool day) and the AC unit is hotter than normal, then overcharging might be your offender. Like finding out you’ve been overdoing it with the hot sauce, it’s time to dial it down.

Checking the Compressor

Next, let’s take a look at the compressor. If it’s faulty, it could be the one causing the high low-pressure. But how can you tell if it’s not doing its job? One tell-tale sign is if the compressor doesn’t turn on. You’ll also notice that it’s not pumping refrigerant as it should. It’s a bit like finding the machine behind your morning coffee isn’t brewing—disappointing, isn’t it?

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Fixing AC Compressor Low Pressure Too High

Found the culprit? Great job, detective! Now, let’s see how we can get our AC compressor back to its old cool self. The fix will depend on what’s causing the problem, so let’s take a look at what you can do in each scenario.

Fixing an Overcharged System

So, we’ve got an overcharged system on our hands. It’s like having an overfilled glass of water – the solution is to let out the excess.

To fix this, you’ll need to remove the extra refrigerant. First, turn off your AC system to avoid any accidents.

Next, connect your AC gauges if they aren’t already, and attach a refrigerant recovery container to the center port of the gauge set.

Open the low side valve on the AC gauges to start letting the refrigerant flow into the recovery container.

Keep a close eye on the gauge readings, and stop when they return to the normal range. Like taking a bit of air out of an overfilled tire, you’re back to a smooth ride.

Repairing or Replacing a Faulty Compressor

If your investigations have led you to a faulty compressor, it’s time to bring in the big guns. The compressor is the heart of your AC system – if it’s not doing its job, the whole system suffers. If the compressor isn’t turning on, isn’t pumping refrigerant correctly, or is making strange noises, it may need to be repaired or replaced.

You might be able to replace a faulty capacitor or relay yourself, but for more complex issues, it’s best to call in a professional. Repairing or replacing a compressor is a bit like heart surgery – it’s best done by the experts.

Preventing Future AC Compressor Low Pressure Too High

Now that we’ve solved the problem, how can we avoid this AC mystery in the future? Well, there are a few tricks you can use to keep those low pressures low.

Regular AC System Maintenance

Just like you go for regular health check-ups, your AC system needs routine maintenance too. This can help you catch any potential issues before they turn into bigger problems. Think of it as preventive care for your AC—it’s worth it in the long run.

Regular Air Filter Cleaning or Replacement

Remember our culprit—the dirty air filter? Well, a clean air filter not only helps keep your indoor air clean but also ensures your AC system runs smoothly. How often should you clean or replace it, you ask? Most manufacturers recommend doing this every 30-60 days. It’s kind of like changing your toothbrush—you wouldn’t want to use an old, frayed one, right?

Ensuring Correct AC System Charging

Our first suspect—the overcharged system—can also be avoided with a bit of care. When you’re charging your AC system with refrigerant, make sure to follow the manufacturer’s guidelines. Think of it as filling your car with gas—you don’t want to overfill it and cause a spill, do you?

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