Why Your Suction Lines Freeze Up

Why Your Suction Lines Freeze Up

It’s a common problem: you’re enjoying the cool, refreshing air from your AC unit, and suddenly—it stops working.

What gives? Your air conditioner has a problem with the suction lines in the system. These tubes are responsible for drawing in cold air to cool the system and expel it back out into your home. When they freeze up, they can cause your AC to stop working entirely or, at best, function at a reduced capacity.

So why do these lines freeze up? It depends on where you live and what kind of AC unit you have. But you can take steps to troubleshoot this problem and get your AC working again as soon as possible.

In this article, you will learn the causes of frozen AC suction lines, how to troubleshoot a/ac frozen suction lines, and when it’s time to get help from a professional ductwork repair and installation expert.

What causes the suction line to freeze up?

In a perfect world, AC systems would never freeze up. But we don’t live in a perfect world, and sometimes you have to deal with the consequences of your AC system freezing up.

But why does it happen? The freezing of an air conditioning (AC) suction line can occur due to several factors, including:

Insufficient airflow

If you’re not getting enough airflow through your AC system, it will start to overheat and freeze. This can cause a frozen suction line AC unit in place.

Low refrigerant levels

If you don’t have enough refrigerant in your system, it can’t heat things up properly. This means that your AC unit will work harder than it should, which can lead to premature wear on your system components—including the AC suction line.

Malfunctioning thermostat

Another cause is a malfunctioning thermostat. The thermostat regulates the temperature of your home by switching on and off at set temperatures, but if it malfunctions or becomes dirty, this can result in your AC not being able to maintain a steady temperature. This will cause your refrigerant lines to freeze over due to extreme temperature fluctuations and an increase in pressure from internal blockages within your system’s compressor motor unit (CMU).

Restriction in the refrigerant flow

This is when the air conditioner’s compressor is not moving enough refrigerant through your system, and it causes a buildup of pressure in your suction line. As a result, the coolant freezes in place and blocks your air conditioning from working properly.

Defective defrost cycle

The defrost cycle is designed to keep ice from blocking the airflow through the AC unit. When this cycle malfunctions, it can cause ice to build up in the AC unit and block its airflow. The result is that your home becomes too cold, hot, or both, and may result in frozen lines.

Oversized AC unit

If you’re using a large central AC unit in a small room, this can cause improper circulation and ac suction line frozen. A smaller, more appropriate unit would solve this problem.

How To Troubleshoot The A/Ac Frozen Suction Line?

It’s not unusual for your air conditioner to work perfectly fine and suddenly stop. There are a lot of reasons why this could happen, but the most common is a frozen suction line.

When the refrigerant in your A/C freezes and expands, it can block the suction line, which means it’s time to troubleshoot!

Here are a few easy steps to get your A/C up and running again:

Turn off the AC

First and foremost, turn off the air conditioning system to prevent further damage and allow the ice to melt.

Check airflow

If there’s no airflow from your vents (or any vents at all), then you probably have a problem with your evaporator coil or drain line. Make sure there aren’t any clogs in either one of these areas by using compressed air or running hot water through them. If there are clogs, use a vacuum cleaner with a brush attachment to clear them out; don’t use anything sharp that could damage the parts inside!

Inspect refrigerant levels

If your air conditioner seems to be working fine except for some freezing up, inspect the refrigerant levels in your system. If too much or too little liquid is in there, this could be causing your problem. To check your refrigerant levels, turn off the power at the thermostat and unplug the compressor for about 15 minutes. Then, open up the compartment where your compressor is located and look for a sticker that has numbers on it. Find this sticker on your unit and write down both numbers (this is also called “pressurizing” a system). Next, pressurize your system by adding 2 lbs of R-22 refrigerant into each side of the system until you reach these numbers (so if one number was 7 lbs and one was 8 lbs, then you would add 10 lbs total). Then do not touch or move anything for at least 24 hours so that everything can settle down properly before turning anything back on!

Check for refrigerant leaks

Check for leaks in the system by visually inspecting any hoses or connections that have been replaced recently or that have been used frequently over time (such as connections at the compressor). If there are any leaks present, then they will need to be repaired immediately by an HVAC technician before driving too far down the road so that damage does not occur with each bump and shake while going down the road! Even though they may seem small at first glance, these tiny pinhole leaks can lead to a significant issue.

Check your thermostat

If it’s stuck on auto-defrost and preventing the compressor from turning off, that could be why your system isn’t working properly. Make sure it’s set to “on” and not “auto.”

Check the defrost cycle. 

If your thermostat is set to “on,” but the compressor still isn’t turning off, check to see if there’s ice covering any of the lines connected to (or leading into) it. If there is, melt it with warm water or carefully chip away at it with a screwdriver until you can get rid of all of it. Then try turning on your AC again!

Evaluate the AC unit size

If you suspect the suction line is frozen on ac and is oversized for the space it is cooling, it may be cooling the air too quickly and causing the suction line to freeze. In such cases, it’s advisable to consult an HVAC professional for Ductwork Repair And Installation In Lodi, CA, to determine if resizing the unit is necessary.

When is the Best Time to Winterize Your Suction Lines?

The best time to winterize your suction lines, or any part of your air conditioning system, is before the onset of winter or when you no longer require cooling. Winterization is typically performed in preparation for colder weather when the AC system won’t be in use.

Here are some general guidelines for the timing of winterizing your suction lines:

Late fall

This is the perfect time to get this done because there’s no chance of freezing temperatures or snowstorms messing things up. Plus, if you do it after the first frost, any ice that forms won’t be able to damage your system until springtime, when everything thaws out again.

When you stop using the AC

If you have central air conditioning in your home (or office), it’s important not to forget about those suction lines. While they’re not as susceptible to freezing temperatures as some parts of your HVAC system (like coils), they can still become damaged if exposed to extreme cold conditions for too long without being drained out first.

Seasonal maintenance schedule

Some homeowners in Lodi, CA, choose to have regular seasonal maintenance performed on their HVAC systems. If you follow such a schedule, including winterizing as part of your fall or pre-winter maintenance routine is a good practice.


We get it. You’ve got questions. So here are some answers to the most common questions we hear from our customers. If you have a question that isn’t answered here, don’t be afraid to ask us! We’d love to hear from you.

Can I use the AC suction line when the temperature is below zero?

Yes, but only if you have a heated hose. The hose will keep your hands warm while you work!

How do I know if my AC suction line is frozen?

If it’s not moving at all, then there’s a good chance that your line has frozen and needs to be thawed out. If it seems like it’s moving slower than usual, then there’s also a good chance your line has frozen and needs to be thawed out. If you’re not sure, contact us! We can help you figure it out.

How do I unfreeze my AC suction line?

You can unfreeze your AC suction line by pouring warm water over it with a garden hose or bucket until it’s thawed out. This will usually take less than an hour, depending on how long the pipe has been frozen. You can also use a blow dryer set on high heat to melt any ice that’s still blocking the pipe. Be careful when using this method because it may cause severe harm to other parts of your system if used too quickly or too often!

Should I remove the ice from my suction line before trying to melt it?

No! Removing ice from your suction line can cause damage. If there’s too much ice in your suction line, first use a hair dryer or heat gun to melt as much of it as possible. Then, use a stiff brush to remove any remaining ice from the tube.

How long will it take for my AC suction line to freeze?

That depends on where you live! If you live in a cold place like Lodi or Wallace, it could take several hours or overnight. If you live in a warm place like Florida, it could take several days or longer to freeze. If you’re not sure where you live, check with an expert at Blackwell Services. They can help you find out how quickly your AC suction line will freeze based on your location and other factors like altitude and humidity levels.

How do I prevent my AC suction line from freezing?

Make sure your air conditioner has an adequate drainage system. If possible, place a pan under the unit to gather any water that may spill out during maintenance or cleaning. If you’re using a window unit, make sure it’s located as far away from other living spaces as possible—this will help keep it warmer and, therefore, less likely to freeze in winter months.

What is the cost of ductwork repair and installation?

It depends on a few factors: what needs to be fixed, the size of your ducts, the extent of damage, and whether you want new ducts installed or just repaired. In general, you can expect to spend between $1,000 and $3,000 for repairs and installation.

Is it possible to install AC ductwork without having to take down walls?

Yes! In fact, this is one of our most common requests. When we install your new AC ducts, we will ensure they go through your ceiling and not through a wall so that you don’t have any insulation or insulation displacement issues. In addition, we will also ensure that the piping doesn’t interfere with any other utilities like electrical wiring or plumbing pipes.

How much does ductwork repair cost?

Ductwork repair costs will vary depending on the extent of damage, so you should contact an expert for more information. If the ducts are damaged beyond repair, a replacement will be needed.

Need Help? Call Professionals For Ductwork Repair And Installation In Lodi, CA!

If you’re having trouble with your frozen suction line, don’t worry. We’ve got you covered.

When you call for Ductwork Repair And Installation In Lodi, CA, we’ll be able to help you! We know what it’s like to be a homeowner: sometimes, things go wrong. That’s why we’re here. 

Whether you’re looking for HVAC Ductwork Services in Lodi or elsewhere, Blackwell Services is here to help! We can help you get your HVAC system functioning at peak performance levels again so that you can enjoy a comfortable living environment.

We have over 20 years of experience working with all types of ductwork problems, including frozen lines. We’ll send out one of our expert technicians to your home or business as soon as possible—even on weekends and holidays—to diagnose the problem and fix it for good.

Our team of experts is well-trained in all aspects of HVAC repair and installation, so no matter what problem you’re having with your ducts, we’ll be able to fix it fast. We also offer a variety of services, including:

– Ductwork repair

– Ductwork installation

– Ductwork cleaning

– Ductwork insulation

– Circulation system installation

– Heat recovery ventilators (HRVs)

– Air conditioning repairs

Our licensed, certified, and insured technicians at Blackwell Services are here for all your heating and cooling needs—from repairing old systems to installing brand-new ones. We’ll work with your budget so that whatever we do for you is within reach financially. And we’ll always treat your home as if it were our own by protecting it from dust during the repair or installation process!
So If you want to breathe easier this winter (and beyond), call Blackwell Services at (209) 369-0991. Our technicians will come out to evaluate your ductwork and give you a free estimate on potential repairs or replacements.

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