What are the Most Common Parts that Fail on a Gas Furnace in the Winter?

A Guide to Natural Gas Furnace Repair

Natural gas heat is a comfortable choice. It produces heat quickly and reliably. When you think about it and use your imagination, it is just a few steps away from a fireplace, and who doesn’t consider a warm fireplace comforting?

Comfortable and cozy fireplaces required a lot of maintenance, bringing kindling and wood in and moving ashes and exhaust out. Natural gas furnaces also require significant care and maintenance, and occasional furnace repair. Here is a list of the most common furnace repair issues required with natural gas furnaces.

Maintenance Tips and Furnace Repair Essentials

1 The Ignition System

Older furnaces had a pilot light, a small flame that constantly burned to ignite the furnace’s burner assembly. Newer furnaces have an electronic ignition system that creates a spark whenever ignition is needed. Separate sensors shut off the gas if a flame is not produced, shut off the gas if the heat becomes excessive, and keep the blower motor running until the heat is dissipated. All these sensors are rather delicate and sensitive to dirt (soot). Careless cleaning can be destructive and harmful.

The presentation of this problem will usually be a system that does not turn on. The solution is a good cleaning by a furnace repair professional trained to clean sensitive parts.

2 The Burner Assembly

The products of burning natural gas are carbon dioxide and water vapor. The burner assembly is cast iron, with extremely small openings that release the gas for combustion. That means that the burner assembly is susceptible to rust corrosion.

If rust creates larger-than-desired holes or creates flakes that interfere with combustion, it creates incomplete combustion and reduced heat output. A technician will need to wire brush the rust away and inspect the burner assembly for corrosion damage.

3 The Heat Exchanger

Remember, burning natural gas creates carbon dioxide and water vapor; incomplete combustion also produces carbon monoxide. The products of combustion cannot be blown into the home, so the furnace uses a heat exchanger. A combustion chamber houses the burner assembly. The hot gas travels through a network of baffles to slow it down. The combustion chamber is surrounded by another closed chamber, the heat exchanger. The blower motor pushes air into this exchanger, where it encounters the hot baffles of the combustion chamber. The air that blows into the home is warm AND safe.

Since the baffle network and exhaust pathway are constantly exposed to hot water vapor, it is important to care for it, watching for rust, corrosion, or cracks that might develop. The technician will err on the side of caution to protect the home’s occupants.

4 The Gas Valve

When a mechanical valve is unchanged for years, it can corrode open (or shut). It is very important to be able to shut the gas supply off, so it is often necessary to replace this valve as a safety precaution.

5 Common Components

All furnaces have common components that require furnace repair and maintenance, as they would in any other type of system. The air filter needs to be changed regularly—at least once every three months. The thermostat is the ON/OFF switch, and it is battery-powered, so the batteries need to be changed annually. The blower motor is the only moving part in the system. It turns a large cage fan, and it moves about 800 to 1,200 cubic feet per minute in most-sized homes. Over time, the blower motor belt may wear and break, or the motor mounts may break.

Homeowners should change the air filter as needed and should change the batteries annually. A furnace repair technician will need to make any other repairs.

Schedule Your Professional Furnace Repair Today

Maintaining the delicate balance of your heating system is essential for both your home’s comfort and your family’s safety. From cleaning soot-covered sensors to inspecting the heat exchanger for dangerous cracks, these complex tasks require the steady hand of a trained professional. Attempting to handle rusted burner assemblies or corroded gas valves on your own can lead to costly damage or hazardous conditions. Our expert technicians have the tools and experience necessary to ensure every component of your natural gas system is operating at peak efficiency. Don’t wait for a small ignition issue to turn into a total system failure in the middle of a cold snap.

Call R.M. Mullinix today at 979-822-4079 to schedule your furnace repair appointment and enjoy the peace of mind that comes with a safe, warm home.

December 29, 2025

What DIY Maintenance Should I Do for My AC in the Winter?

11 Simple DIY AC Maintenance Steps for a Warm Winter

The National Oceanic and Atmospheric Administration has predicted a warmer winter. Bonus! A warmer, drier season means lower utility bills. Again, bonus! With a mild winter, thoughts turn toward an early cooling season. Now is a perfect time for completing do-it-yourself AC maintenance tasks on your air conditioner. What can you do?

Be safe. Before attempting to work on this very important mechanical system, with 240 volts running through some of the components, flip the circuit breaker marked Air Conditioner for your own protection. Use every safety precaution, but first take away this danger before working on the air conditioner.
The first tools to use are your eyes. Make observations about the components you observe, sights that you most likely rarely see. Make note of any rust, poor connections, or discolorations. You might not be qualified to correct these problems, but you can point them out to an air conditioner technician.
Start by replacing the air filter. The air filter is the same for both heating and cooling. Even poor air filters work remarkably well, collecting dust, pollen, and other airborne contaminants. But this collection will quickly cover the filter and restrict airflow unless changed; it is recommended that air filters be changed at least every three months. Find the air filter at the base of the air handler, where the return air vents bring air from the home to the unit. Slide the old filter out and replace it with a new one of the same size as the old.
Make some general observations about the tubes, wires, and ducts that enter and exit around the air handler.
Step outside to the condenser unit. Observe the immediate surroundings. The condenser draws a large amount of air into it, so the surrounding 18” to 24” needs to be clear. Clean away any leaves, limbs, or trash. Trim away shrubbery or ornamental grass to ensure maximum airflow.
The condenser unit is hollow with a large fan. It is not unusual for a few leaves to make their way inside, but if there are massive amounts of leaves, they should be removed. Remove the cover and use a shop vac to remove the leaves, avoiding contact with everything else inside. Replace the cover.
Remove the outside covers of the condenser unit and observe the sides of the condenser. It is made of a network of tubes, covered in fins. This network transfers heat from inside the home to outside the home. As air is drawn across the network, pollen, dust, and other contaminants stick to the tubes. This collection needs to be washed away, but washed away gently. Use a garden hose, not a power washer. A power washer can damage the fins and tubes.
Observe the condition of the fins. The fins are extremely thin and fragile. They can be damaged by contact. If a section of the fins is bent and damaged, they can be straightened with a fin comb, available at many hardware and home improvement stores.
Return the cover pieces.
Observe the unit, noticing any damage that might have occurred. Look for telltale organic material that a rodent might have introduced to the unit as a nest. They often choose enclosed, tight spaces. Tight spaces in a condenser unit also contain sensitive electrical controls, so it is best to bring this fact to the attention of a technician.
After the AC maintenance tasks have been completed, flip the air conditioner circuit back to the ON position.

Completing do-it-yourself AC maintenance tasks is no substitute for annual maintenance with a trained professional technician. Make sure to schedule this inspection as well.

Essential AC Maintenance Tips for Homeowners

While performing these basic safety checks and DIY tasks is helpful, not all homeowners can confidently handle every step or truly inspect the complex internal components of an HVAC system. Ensuring your safety and the longevity of your unit requires specialized expertise beyond simple cleaning.

For thorough system calibration and advanced diagnostics, trust the professionals. Call R.M. Mullinix today to schedule an appointment for your comprehensive AC maintenance tune-up and guarantee worry-free comfort all year.

November 26, 2025November 26, 2025

Is Winterizing My AC Unit Recommended?

Winterizing Your Unit: Essential AC Maintenance for the Off-Season

With the coming of deep Fall, the cooling season has come to a close, and the heating season has begun. Since the air conditioner will not be necessary for a few months, you might consider winterizing your air conditioner. Prior to considering winterizing steps, you must ensure these two facts.

Make sure that your air conditioner is not also a heat pump. A heat pump system reverses the process of air conditioning and heats the home. Do not winterize a heat pump.
Make sure that those days when air conditioning might be needed have passed.

Winterizing an air conditioner can reduce the wear and tear of the winter weather. As you know, Texas winter days can turn quickly from warm to hot to cold in one day. Of course, the goal of winterizing is to prepare the air conditioner and have it ready for the warmth of Spring.

End-of-Season AC Maintenance: Preparing Your Condenser for Winter

Here are some things to do and some things not to do:

Do trip the breaker for the air conditioner, shutting off power to the condenser. Do not shut off power to the air conditioner if it is a heat pump. If you are unsure, check the thermostat. A heat pump thermostat will have two heat settings: HEAT and Em HEAT or Aux HEAT.
Do inspect the condenser and its immediate surroundings. Fall and Winter tend to be very windy, and leaves and limbs are falling. The wind can push leaves and trash against the condenser. Since the condenser needs lots of air flow to release heat into the atmosphere, remove the debris and clean the area. You might need to repeat this cleanup.
Do consider a protective cover for the condenser. Some folks will cut a piece of plywood slightly larger than the top of the condenser and place something heavy on top to prevent the plywood from blowing away. Some homeowners will purchase a mesh cover for the condenser; Bungee cords can hold the mesh in place. The covers deflect leaves and small limbs from getting inside. It also does not make the condenser an attractive, warm space for rodent pests. Do not use plastic or heavy fabric to cover the condenser, since these tend to reduce airflow. Moisture that enters the condenser but does not have enough airflow to evaporate can promote mold over the winter. Also, a cover that reduces airflow tends to encourage pests to make a Winter home away from the wind and cold.
Ensure that the condenser is properly installed. The condenser needs to be installed on a concrete pad and secured with straps or bolts to prevent wind damage. In some locations, the condenser needs to be elevated to lift it above potential localized flooding.
Do consider waxing the condenser’s cover. Air conditioning components are designed to handle normal weather—rain, sleet, frost, and even ice and snow. If you are concerned about how the weather might affect the condenser, put a coat of automotive wax on the condenser cover. It can prevent rust on the exterior of the condenser. It will need to be reapplied.
Do not worry about the condenser being damaged by normal rain.
Do not forget annual maintenance. This important step ensures that the condenser functions efficiently, lasts as long as possible, and with fewer repairs.

Maximize Lifespan: Schedule End-of-Season AC Maintenance Before Winter

Don’t just cover your condenser; ensure it’s professionally cleaned and inspected before winter sets in to maximize its lifespan and efficiency. Scheduling end-of-season AC maintenance guarantees your unit is protected from winter damage and ready for peak performance next spring. For expert winterization and comprehensive service you can trust, call Mullinix AC and Heating today to schedule your essential appointment.

For more information about R.M. Mullinix and our AC maintenance College Station services, schedule an appointment or visit our HVAC repair and AC maintenance information page.

November 18, 2025

Based on its age, how long will my furnace system last?

How Long Will Your Furnace Last? Factors That Determine Its Lifespan

The temperature is dropping steadily, as it does every year during this season. This may have prompted the first call for heat for this Fall/Winter. It might also have triggered the question: “How many more heating seasons before I need to replace my furnace?” There are typical answers to this question. They may or may not agree with your experience. There are some contributing factors to the answer to this question. Some factors are impacted by the homeowner’s input, and some factors are unrelated to homeowner activities. Let’s look at a few of these factors.

Key Factors That Impact Your Furnace Durability

Brand makes a difference. Some manufacturers have a very good reputation for quality, performance, and durability. Some manufacturers focus on the bottom line, creating the most inexpensive system to meet consumer demand. When making a purchase, it is beneficial to do a little research and determine which brand is ranked highly in the HVAC system manufacturing market.

Climate and usage matter. A furnace in a cold region will have many more heating cycles per year than a warm climate heater. A family with an at-risk family member is likely to use a higher temperature setting for health and comfort. A homeowner dedicated to energy efficiency is more likely to use a lower setting, requiring fewer heating cycles. Homeowner decisions have an impact on longevity.

Scheduled maintenance can add years. Regular inspection, testing, and cleaning of a furnace reduces stress to components and ensures that the system functions properly. That includes:

Changing the air filter often—every three months is right for most homes.
Cleaning coils and checking the refrigerant for heat pump systems.
Removing rust and inspecting the burner assembly and heat exchanger for natural gas furnaces.
Testing the electrical controls and motors to uncover weaknesses that develop in all furnace systems.

Regular furnace maintenance has been measurably shown to add as much as five additional years of serviceability to furnaces and air conditioners. Making timely repairs will also ensure the system does not “limp” along, functioning poorly.

The largest factor that has nothing to do with homeowner activity is the age of a furnace. The typical furnace lasts between 15 and 20 years. You have heard this quite often, but might not understand where this figure comes from, so here is a little history that is the foundation for the statement.

Older furnaces were manufactured with thicker steel and heavy-duty components. However, “thicker” and “heavy-duty” were also more expensive.
High cost and consumer demands for lower cost led to furnaces being manufactured with lighter materials, resulting in less expensive systems.
In 1987, the National Appliance Energy Conservation Act set minimum standards for materials in appliance manufacturing. Furnaces were required to be built with an engineered longevity of 15 to 20 years.1

Systems are built with a target longevity to meet consumer expectations of both longevity and affordability.

So the unique, individual answer to this question is really unknown, but these factors give a much clearer understanding of the possibilities for your system. To help with decision-making,

Determine the age of your system. If you were not present when the existing system was installed, ask your HVAC company for help in determining the age.
Schedule regular maintenance for the best possible results. If you have not been maintaining your furnace, begin now and give your furnace the best care possible.
Plan a replacement date. Begin a budget plan to set aside money for replacement. Be alert for problems, especially as your system approaches the range that most systems need to be replaced.
Avoid waiting until the last gasp of an aging system. It will probably come at a very inopportune time, resulting in a very uncomfortable wait while components are being shipped and the technician’s schedule clears.

Maximize Your Furnace Lifespan: Call Mullinix AC Repair Today!

Give your heating system the care it needs to reach its maximum lifespan with expert service from Mullinix AC Repair. Regular HVAC maintenance is proven to add years of reliable performance to your existing furnace, saving you from an unexpected, costly replacement. Don’t wait for a breakdown; call Mullinix AC Repair today for a comprehensive inspection and proactive heating system repairs. Ensure your home stays warm and your heater keeps running efficiently for years to come!

For more information about R.M. Mullinix and our heater maintenance College Station services, schedule an appointment or visit our HVAC repair and maintenance information page.

1 https://www.congress.gov/100/statute/STATUTE-101/STATUTE-101-Pg103.pdf

October 29, 2025

What is the Best AC Thermostat Setting?

The Best Thermostat Setting for Comfort, Health, and Lower AC Bills

Is there a perfect AC thermostat setting? It is a complicated question, with many facets and some commonsense answers. Let’s look at some basic considerations.

Comfort and Health Considerations

Heating and air conditioning have made a deep impact on modern homes. Air conditioning makes living in the deep south comfortable and healthy. Heating makes the same difference in colder climates. A heating, ventilation, and air conditioning (HVAC) system replaces more dangerous and unhealthy heating and cooling options. The “right” AC thermostat decision will be based on temperatures that protect health and comfort.

Family members with health issues may need special consideration concerning temperature
Family members who are very young or very old may need special consideration

Other setting decisions may affect energy efficiency and energy costs, but health concerns may override these decisions.

Comfort is a personal preference. Expect it to vary significantly between family members and for individuals in different seasons of life.
Older homes with poor insulation, abundant drafts, and extra high ceilings may require a different temperature setting, since heat rises and the floors will be colder than normal.

Saving Energy Made Easy: How to Choose the Optimal Thermostat Setting for Your Home

Human tolerance for temperature variations is actually quite broad; we participate in outdoor activities, from skiing to surfing. Energy experts realize that we can find comfort inside using these tolerances and save considerable energy.

The generally accepted range for comfort lies between 680 and 720 Fahrenheit
However, a family might tolerate summertime temperatures indoors in a range from 750 to 780 while the family is awake, and 720 to 750 while sleeping. Temperature settings above 780 during the summer reduce the number of cooling cycles and do not remove sufficient humidity from indoor air.
A family might tolerate wintertime temperatures indoors in the normal range, 680 to 720, but drop the temperature while sleeping to 670 to 600.
Raising the temperature by 100 during the summer while the family is away is considered prudent (remember the 780 threshold). Lowering the temperature by 100 during the winter while the family is away is also considered prudent.

These figures are significant since they save energy and make the whole system work efficiently. Saving energy saves money as well. The savings are measurable. Research shows that a savings of 1-3% savings for every degree of temperature change. This temperature change needs to last for eight hours or more.

All these tolerances and temperature changes seem very complex and hard to handle. However, a modern AC thermostat is programmable; these setting changes can be scheduled automatically according to preference. As you investigate scheduling changes, remember:

Do not ignore health needs to achieve energy savings.
For temperature changes to lower energy bills, the change needs to total eight hours or more. Focus on overnight changes or while the family is away during the day.
Use your programmable AC thermostat to simplify the desired setting changes at the appropriate times.

Maximize Savings: Get the Most from Your AC Thermostat by Scheduling Pro AC Maintenance

Optimal comfort and efficiency start with finding the perfect AC thermostat setting, but they are maintained by a healthy HVAC system. Before adjusting your programmable thermostat for seasonal savings, ensure your unit is ready to handle the varying demands without strain. Call R.M. Mullinix AC today to schedule a professional maintenance appointment. Our experts will inspect your system and AC thermostat settings to ensure it runs efficiently and reliably, giving you the best results from your chosen settings.

For more information about R.M. Mullinix and our AC maintenance College Station, schedule an appointment or visit our AC repair and maintenance information page.

October 15, 2025

The Simple Truth About Regular AC Maintenance

What Professional AC Maintenance Really Does to Protect Your System

Your air conditioner works incredibly hard each summer. Normal comfort demands an average of 2 to 3 cooling cycles per hour. That means your air conditioner will experience between 9,000 and 13,000 cycles per season. Admittedly, this is plenty of work, and any hard-working mechanical system needs AC maintenance. For this reason, it is not surprising that everyone involved with the air conditioning industry calls for regular inspection and cleaning.

5 Major Benefits of Professional AC Maintenance

Isn’t your air conditioner pretty stable? What could possibly happen that would require professional help?

The air filter needs to be changed. A blower motor pushes cool air into the home and, at the same time, draws it back through an air filter and through the air handler chamber. While the air in your home seems clean, the air filter reveals that it contains dust, pollen, and dander. After a few months, the entire surface of the filter will be covered with these airborne particles. This covering will eventually restrict airflow and hamper the cooling process, so it is important to change the filter regularly, about every three months.
The air conditioner has two coils: the condenser coil outdoors and the evaporator coil indoors. The coil is a collection of tubes, covered with very thin aluminum fins, allowing the ready transfer of heat. Dust, pollen, and other airborne particles collect on the tubes and fins and act like an insulating blanket, reducing the amount of heat that transfers. A garden hose and a gentle cleanser will wash these particles away. The evaporator coil gets cold. Hot, moist air is blown across the coil, and the excess moisture condenses, drips down to a pan, and is drained away. Cool, dark, wet surfaces promote the growth of algae, and the algae can clog the drain line, so the technician will make sure to clean the drain pan and drain line.
The whole system relies on a refrigerant compound. When it is compressed and the pressure is suddenly released, the compound gets cold, the source of the cooling. This compound is constantly under pressure, and if any of it leaks, the whole system struggles. The struggling system will work so hard, it will eventually fail catastrophically.
The whole air conditioning system is powered and controlled by complex sensors, switches, and control mechanisms. Each part relies upon other parts, so if one switch is weakened, it stresses surrounding components. An inspection with an electrical tester can uncover any weakness. The main switch for the air conditioner is called a thermostat. The technician will replace the batteries in the thermostat and calibrate it as needed.
Other parts may exhibit general wear. The blower motor is usually moved by a belt, and the belt may show signs of wear. Connections may become loose. Ductwork may vibrate and work loose, and leak air. A trained technician will look closely at the system and make these small repairs.

What are the results of an inspection and AC maintenance visit?

The whole air conditioning system will cool better, remove more humidity, and clean more particles, making the home more comfortable.
The air conditioning process will require less energy and cost less to operate
Small issues will be caught before they become major (and expensive) problems
Regular AC maintenance generally adds five years of useful life to an air conditioner, which is an additional cost-saving

Why Professional AC Maintenance is a Must

Give your hard-working AC the essential care it deserves to keep it running efficiently and reliably. Stop small issues like coil dirt and algae before they cause catastrophic system failure and huge repair bills. Scheduling your professional AC maintenance visit now will help you restore efficiency, lower your energy costs, and add years of life to your investment. Call our team today to book your inspection and ensure worry-free cooling all season long!

For more information about R.M. Mullinix and our AC maintenance College Station, schedule an appointment or visit our AC repair and maintenance information page.

September 29, 2025

AC Repair vs. AC Replacement

The Cost of AC Repair vs. AC Replacement: A Fall Checklist

With summer in the rearview mirror, it is time for cooler temperatures and pumpkin patch fun. The demand for residential air conditioners has somewhat lessened. It is a good time to assess the strength or weakness of an air conditioner with an inspection.

Occasionally, a routine inspection will uncover the need for AC repair, and the thought can be a little concerning. How much will the AC repair cost? How long will it take? It would be nice to have a few clues to help overcome the stress one might feel over facing necessary AC repair. To be clear, the cost of any repair can only be determined after a careful diagnosis from trained AC technicians. But here are some significant factors that affect the cost of your AC repair.

When to Choose AC Repair over AC Replacement

Timing is everything.

Is the system still under warranty? A manufacturer’s limited warranties might depend on maintenance records, so make sure to read the fine print.
An emergency AC repair made during an extended heatwave will usually cost more than a repair made during normal working hours. Repairs that require evening or weekend hours will result in evening or weekend labor rates.
If your air conditioner is inspected and maintained regularly, the chance of catching a minor issue early is much higher. If the minor issue is missed, it can weaken other parts related to the problem component.
For service call information, it is as easy as making a phone call; there is usually a minimum for the call and an hourly labor rate that is disclosed. Expect the hourly rate on evenings and weekends to be higher than the normal rate.

Component Costs

The complexity of the repair will greatly impact the cost. Obviously, a minor repair with inexpensive component replacement will cost less than replacing a major component.
The age of an air conditioner is an important factor in determining component costs. AC Repair costs will also determine whether repair or replacement is more cost-effective.
The average air conditioner lasts between 15 and 20 years. A system that is approaching or exceeding this timeline might be difficult to repair, and the cost might be extremely high. Parts might be rare or unavailable for older systems.
The age of the system also affects the refrigerant the system is designed to use. Engineers and the US Environmental Protection Agency are constantly searching for more efficient AND more eco-friendly refrigerant gases, since older versions negatively impact the ozone layer. Older refrigerants have been banned, and the available supply will be extremely expensive. Repairs that require the removal and replacement of such refrigerants can be cost-prohibitive.

Mullinix AC Repair Can Help Evaluate AC Repair versus AC Replacement

Evaluating the cost of AC repair versus replacement requires a careful diagnosis from a professional. Key factors include the age of the system, whether it is still under warranty, and the cost and availability of replacement parts and refrigerants. Ultimately, for older systems, a replacement may be more cost-effective due to high repair costs and improved efficiency of new units.

For more information about R.M. Mullinix and AC maintenance in College Station, schedule an appointment or visit our AC repair and maintenance information page.

September 18, 2025

The Surprising Benefits of Fall AC Maintenance

From Hot to Healthy: How Proper AC Maintenance Improves Your Home’s Comfort Level

While summertime is fun and full of adventure, it is also hot and humid. While we can accommodate the heat, finding relief in air-conditioned spaces is essential for health and comfort. This reminds us that air conditioning systems work very hard for a long cooling season. The average AC system in our region performs more than 12,000 cooling cycles per year. In a few weeks, the same system will begin the heating season, another period of hard work, with a similar number of heating cycles. Without proper care, a cooling and heating system will result in some very negative outcomes and need AC maintenance.

Your AC Maintenance Checklist

Proper AC maintenance of your system will result in very positive outcomes. Regular AC maintenance will:

Extend the life of any air conditioning and heating system. Maintenance usually uncovers weakening and failing parts and makes adjustments along the way. Maintenance creates a kind of boost for the system. Regular maintenance can reduce the number and intensity of repairs.
Replace the air filter, a crucial improvement for the entire system. A dirty, clogged filter will reduce the airflow through the unit, reduce the system’s efficiency, and negatively impact the indoor air quality. This is an extremely important step, and it should be repeated quarterly.
Constant use will reduce the energy efficiency of these systems, but regular maintenance will give efficiency a boost as well. The air conditioner might not regain the efficiency of a new system, but it will make a measurable difference, discernible by comparing utility bills year-to-year.
Maintenance improves comfort and health for the entire family. Improved efficiency reduces the possibility of hot spots or difficulty keeping up with extreme temperatures. It also improves indoor air quality, keeping family members healthier.

What a Professional Looks for During an AC Maintenance Inspection

What is involved with an AC maintenance inspection that is so important to the air conditioning and heating system? Each component is inspected individually.

The electrical system is inspected thoroughly. Connections are tightened and inspected. Some control mechanisms, such as capacitors and sensors, weaken over time and jeopardize proper function. Localized weakness can create a cascade of weakening with other electrical parts.
The ultimate ON/OFF switch, the thermostat is battery-powered, and the batteries need to be replaced regularly. Occasionally, a thermostat will need to be recalibrated to ensure the timeliness of heating and cooling cycles.
The refrigerant level will be checked, a very important component of air conditioners and heat pumps. The pressure level of refrigerant gas must be maintained within a narrow range. Loss of pressure will reduce or curtail the cooling/heating function. It can also cause major damage to vital (and expensive) components.
There are two major components that need to be cleaned annually: the outdoor condenser unit and the indoor evaporator coil.
- The refrigerant has collected heat from inside the home and needs to release heat into the atmosphere. The condenser walls are composed of tubes and fins, designed to conduct heat energy. Pollen, dust, dirt, and debris collect on the tubes and fins, preventing the ready transfer of heat. The reverse is true indoors.
- The refrigerant inside is cool, attracting that heat to be carried outdoors. Dirt, dust, dander, and other airborne particles collect on this coil and reduce the transfer of heat. Simple soap and water are generally enough to clean the offending particles away, a necessary task in AC maintenance.
There are a few moving parts with an air conditioner, but our technician can inspect the blower motor belt and lube accessible bearings.

Prepare for Fall with AC Maintenance From Mullinix AC and Heating

Investing in professional AC maintenance is the single best way to protect your home’s comfort system and your family’s well-being. By addressing small issues before they become major problems, you extend the life of your unit, improve its energy efficiency, and ensure a healthier living environment. Make fall AC maintenance from Mullinix AC and Heating a non-negotiable part of your annual routine and enjoy the peace of mind that comes with a system that works as hard as you do.

For more information about R.M. Mullinix and our AC maintenance College Station, schedule an appointment or visit our AC repair and maintenance information page.

August 26, 2025

Essential AC Repair Tips for Common Issues

AC Repair: 3 Common Problems When Your Air Conditioner Blows Hot Air

It might happen gradually, over several months, with very few indications that demand attention. Or it might happen suddenly, overnight, or during the day while everyone is away. When it happens, the home, which should be as cool as ever, is very hot and very humid. The sudden turn of events can be quite frustrating and confusing. After the initial shock, it is time to take action and solve the problem. Are you ready for this?

First, find the air conditioner contractor that seems the most natural to you. That might be:

The contractor whom you use the most often, for maintenance and repairs
The contractor whose name and contact information is attached to the air conditioner/furnace components

Before making a call, do some inspections and make some observations.

Here are the most common issues that cause air conditioning systems to continue to function but blow hot air.

AC Repair 1: A Clogged Air Filter

Even though air filters are mentioned often by manufacturers, contractors, and the U.S. Department of Energy, homeowners continue to neglect this essential action. Here is why air filters are so important.

Just beyond the air filter is a chamber where cold refrigerant gas meets the hot, humid air from the home combine. The humidity condenses on the tubes and drains away. The air quickly cools and is transported back into the home—mission accomplished.
Air filters are very efficient, removing dust, pollen, and dander with every cooling and heating cycle. When the filter is not changed regularly, at least every three months, sufficient dust collects, enough to reduce the air flow through the air conditioner.
When insufficient air passes into this chamber, it produces great stress on the whole system. The refrigerant in the tubes remains cold, but cooling does not move into the home.

Replace the air filter and observe whether cool air moves into the home. Remember to change the air filter on a quarterly basis.

AC Repair 2: Refrigerant Leak

This is a more complex problem. The refrigerant is a chemical formula that readily changes from gas to liquid, and in the process readily accepts, transports, and releases heat. This refrigerant is always under pressure, whether as a gas or liquid. The slightest flaw in the pipe or pinhole in the soldered joints can allow the refrigerant to leak out quite quickly. Evidence of a refrigerant leak includes:

The loss of refrigerant often causes ice to develop around the tubes containing refrigerant
Ice can develop inside or outside
If you miss the ice, it will melt away. If the ice melts indoors, you might observe a watery mess, perhaps enough to cause some localized water damage.

It takes training and certification to handle refrigerants, so there is nothing a homeowner can do.

AC Repair 3: A Faulty Thermostat

The thermostat, located on an inside wall away from the sun, can cause problems that end cooling from the air conditioner. Here are some things to observe.

Look at the thermostat face for a “Low Battery” indication
Look at the thermostat face for the temperature; it will be the largest number on the thermostat. It will probably be uncomfortably high for the inside of a home.
Look at the thermostat face for the temperature setting. This setting should be much lower than the indicated temperature. If the setting is too high, move it to a lower setting and observe whether the temperature returns to normal—cool.
Look at the thermostat face to ensure the thermostat is set on COOL.

Before calling the AC repair technician, determine the age of the system components. This can be determined by the model/serial number plate. Knowing the age of the system will be very helpful for anyone making an AC repair.

When your AC is blowing hot air, the problem could be a simple fix or a serious issue. This article breaks down three common problems—a clogged air filter, a refrigerant leak, or a faulty thermostat—that can stop your system from cooling. By understanding these issues, you can troubleshoot the problem yourself or be more informed when you call for professional AC repair.

For more information about R.M. Mullinix and our AC repair College Station services, schedule an appointment or visit our AC repair and maintenance information page.

August 21, 2025

Understanding Your HVAC System Summer Stress

Is Your HVAC System Failing? Spotting the Signs of Trouble Before It’s Too Late

To paraphrase Thomas Paine, “these are the times that try” your HVAC system; months of very hot, humid days, interspersed with a few weeks of heat waves with extremely hot temperatures. Such extreme temperatures put stress on your HVAC system and expose any weakness in key components. It is no wonder that AC repairs and AC replacements peak during the months of July and August.

Common HVAC System Repairs Needed During These Times

Air Filter Changes. The efficiency of air filters in cleaning indoor air is also problematic. When the filter becomes completely covered, it restricts the airflow that can pass through. Airflow is very necessary for air conditioning, so when the amount of air is reduced, it reduces the amount of cooling an air conditioner can achieve. This becomes very evident during hot summer days. Make sure to change the air filter quarterly.

Evaporator Buildup. The air passes through the air filter and across the evaporator coil. The evaporator coil is very cold, so excess humidity from indoor air begins to condense on the coil and drip onto the drain pan, and is allowed to drain away. Any dust or pollen that passes the air filter is likely to collect on the evaporator coils and create a wet mess. The wet dust and pollen inhibit the transfer of the heat from the air and the cool from the coils. The mess needs to be cleaned away.

Condenser Coating. The outdoor air conditioner component is called the condenser unit. While the walls appear solid, they are actually a network of tubes and fins. A large, central fan draws air through the network to cool the refrigerant gas inside. The network acts as another air filter, since pollen, dust, and debris get captured on the tubes and fins. These things need to be washed off of the condenser walls to ensure adequate cooling can take place.

Electrical Weakness. An air conditioner is controlled by very sensitive sensors and switching devices. Common air conditioner use wears these control mechanisms. Eventually, the wear weakens their ability to sense and direct electrical flow. Component weakness reduces an air conditioner’s effectiveness when the family needs air conditioning the most. Special tools and a trained individual is required to detect problems with air conditioner controls.

Some problems that may occur with your air conditioner:

Poor airflow
Smell air coming from vents and excessive dust
Poor cooling performance
Loud or unusual noises
Water leaking from the air handler cabinet
Ice buildup on indoor or outdoor components
Hot spots that don’t get enough cooling
Water leaking from the air conditioner

Call our trusted technicians to inspect and make repairs. Do not delay, since the demand for AC repairs may mean waiting for an available technician. Remember, these problems will not go away by themselves and can get worse over time.

Protect Your Comfort and Your Wallet: Essential Care for Your HVAC System by Mullinix AC

It’s clear that your HVAC system is under immense pressure during peak summer heat, and ignoring the warning signs can lead to major, costly breakdowns. By being proactive and addressing common issues like dirty filters and coils, you can prevent small problems from becoming emergencies. Don’t wait until your system fails completely; a timely repair can restore your home’s comfort and keep your HVAC system running efficiently all season long.

For more information about R.M. Mullinix and our AC repair College Station services, schedule an appointment or visit our AC repair and maintenance information page.