How I Add Refrigerant to a Central Air Conditioner
Hey HVAC techs! I’m Greg Fox, and today we’re going to talk about adding more refrigerant to an air conditioner. I wanted to expand on our recent AC troubleshooting series by going into each part of its sequence of operations. This week, it’s the refrigerant.
Now, I’m not going to get into the legalities and moral issues here of refilling refrigerant on a system that is leaking, but you should know a few things:
- Refrigerant is expensive for the customer – If you have to keep refilling their refrigerant, which we do not know how often that will be, it can add up quickly.
- They know their air conditioner better than us. If we’ve never been to their home to refill their refrigerant before, there’s no reference for knowing how BIG their refrigerant leak is or WHERE the leak is.
- The customer could lose all of their refrigerant tomorrow if they have a significant leak… or if it is a small leak, the refrigerant could last them all year or longer.
Let’s go over some basics to charging an air conditioner on your average 90-degree day in the middle of summer. Upon arrival at the house, your customer tells you the air conditioner worked just fine last year, but this year the system seems to run non-stop, especially as the summer days get hotter and hotter. You ask the customer, “Have any other technicians been out to make repairs on your system since last year?” It’s very likely the customer will say no.
There’s a lot of things that can affect the refrigerant charge. Just remember, for the sake of time, we’re keeping this dialogue short, so we can get to the point of charging the system up.
I like what Bryan Orr mentioned in an article I read. He said,
“We need to set up equipment so that it won’t freeze during normal operating conditions. At the very least, the typical residential A/C system should be set up so that the return air temp can get all the way down to 68° and still be just above freezing at the evaporator coil.
Let’s say it’s 78° in a house on an R410a system, and your suction pressure is 108 PSI. That means your suction saturation (coil temperature) is 35°… so the coil won’t freeze.
However, the coil temperature will drop approximately 1° for every degree the return temperature drops.
Remember, at 78° inside, the evap coil was at 35°, So if the customer sets it down to 74°, the saturation would get down to 31°, and the will start to freeze.
Knowing this, let’s grab your temperature probe and check the return air and the supply air. Here you notice the difference between the two is about 8 degrees. As a tech, you know the split should be around 18 to 22 degrees.
Next, you head outside and feel the suction line to see if it’s cold. Now, there is some validity to the old term, “beer can cold” but it should not be the measure you go by to check the refrigerant charge. It can, however, give you a clue as to the condition of the system. In this case, the suction line at the AC is barely cold. Now, I’m not always a huge proponent of hooking my gauges up to a system every time I go out to diagnose a system, but in this case, we can tell something’s not right with the cooling system, so in this case, I want to see what is going on inside of it.
Hook your hoses up to the liquid and suction lines. Be careful of blowback so you don’t freeze your hands. Follow all safety precautions.
Now, what do you see on your suction side? I like my techs to talk to me about the evaporator coil’s TEMPERATURE and the TEMPERATURE of the condenser coil. When I’m on the phone trying to help a tech out in the field, it’s hard for me to remember all the pressure-temperature ratios between the different refrigerants we use.
So if someone tells me the evaporator coil is 40 degrees, I can immediately tell the coil is not freezing. If someone tells me the temperature of the condenser coil is 140 degrees, I can immediately translate that to an outdoor coil that is under some seriously high pressure.
On the refrigerant gauge, the outer circle and those numbers are the pressures. The inner rings of numbers reflect the temperature. This is how I want my techs to communicate pressures to each other. It’s more efficient this way. Most gauges these days have a green ring for R22 and a pink ring for R410. The pink ring’s numbers are what we are using for evap and condenser coil temperatures on a 410 system.
Here we see that the evaporator coil is at about 20° F. For proper refrigerant levels, the image I want you to project in your mind is this. Our end-goal here is to have liquid refrigerant reach all the way to the TXV at the evaporator coil to meter the refrigerant appropriately. Right now, there’s not enough liquid in the system to do that. This means vapor is making its way to the metering device, and we’re not giving the coil enough refrigerant to interact with the speed of the blower air moving across it.
We need the perfect balance of airflow and refrigerant pressures to create that 18 to 22-degree temperature split we are looking for.
Let’s suppose this system holds 10lbs or R-410a. In my mind, I’m thinking the system is about halfway charged. It’s an approximation, but we have to let the customer know about how many pounds we want to add, so they give you the okay to move forward. Of course, you don’t know for sure, but they should be aware it could be around 5 lbs, and that will cost (whatever, $100 a pound). We need to let them know it could be a couple of pounds more or a couple of pounds less, but either way, we need permission to move forward.
Using a scale is the only way we can know for sure how many pounds of refrigerant we are adding. And it’s cool to let the customer know you’ll be using this too. It’s reassuring to them. This is great for preventing you from overcharging the system too.
My service hoses are already hooked up. I’m going to start by putting my charging hose on the tank of refrigerant. Next, I open the refrigerant tank valve and place it upside down on the scale. With the gauges closed on the manifold, I crack open the connection where the charging hose meets the manifold. Not too much, though. We just want the refrigerant to prime itself up to that point so we get rid of excess moisture and air in the hoses.
Reset the scale back to zero, so we know how much we are adding as the refrigerant enters the system.
I recommend you put an amp clamp on one of the wires leading to the compressor. If you’ve seen my video on diagnosing a bad compressor, you know that the compressor’s amp draw correlates with the refrigerant pressures inside the system. The healthiest compressors will run at around 60 percent of their RLA. When you’re charging up the system, you’ll see the amp draws fluctuate as the refrigerant goes in and settles down. Use your knowledge about the compressor amp draws to monitor your charging process.
Okay! We’re ready to charge! With the charging hose valve open, we’ll start opening the suction side valve. A quarter to half of a turn is enough. There is no approximate amount of time it’ll take to insert 1 lb. of refrigerant. Each situation is different. To know for sure, use your scale.
In this situation where we think the system is about 4 or 5 lbs low, let about 2 lbs flow into the system and wait for 5 to 10 minutes for the system to equalize. Question. How long does it take for the refrigerant to cycle through a typical residential split system? I’d say about 3 or 4 minutes. If you have a different answer, let me know in the comments.
So we see now the low side has come up to about 27 degrees or 92 psi. Our evaporator coil is still freezing. Let’s add two more pounds and wait. I know there’s a lot of pressure on techs to get their calls done quickly so they can get to the next one, but it’s essential to let the system stabilize before adding more refrigerant. If you add too much, too soon, you could see the pressures skyrocket insanely fast. And now you have to recover some refrigerant into a separate tank which takes even more time!
Now we are getting close to 32 degrees or about 100 psi on the suction side. From here, we want to start dialing our subcool to whatever it is the manufacturer recommends. This system says 10 degrees subcooling on a 95-degree day. Let’s get a temperature probe on the liquid line and start getting our reading from it. We’re going to be subtracting the high side’s temperature and the liquid line’s temperature to come up with our subcooling.
Add refrigerant a little at a time until the difference between those two numbers is 10 degrees. There’s nothing tricky about this. Just don’t add too much too fast. Add refrigerant and wait for the numbers to stabilize.
You’re going to be looking for the low side pressure to be around 40 to 42 degrees or 125 psi. The high side pressure/temperature will likely settle around 15 degrees above the outdoor temperature. So on a 90-degree day, you may end up with a high side temperature around 105 degrees. If you can get your numbers around this area, you’re close! But let’s really get it dialed in. Get that subcool to 10, plus or minus 2 degrees.
I will tell you; it takes longer to move the needle on your gauges when there’s less refrigerant in the system. As the system starts getting close to the proper subcool, you’ll want to finesse the time you keep the manifold open, allowing refrigerant into the system. Overcharging can happen quickly, especially on a hot day.
Getting close to your 10 degrees subcool? Cool!
Once you get it to this point, check your temperature split inside. Is it around 18 to 22 degrees? Great! You’ll notice the liquid line is a little bit warmer than the outdoor temperature. Also, the suction line will be damn near “beer can cold!”
Test the system while it’s running. Get your amp draws on the condenser fan motor and compressor. Cycle the system on and off at the thermostat to make sure the system is operating correctly. If it is, you’re good to go.
Well, I hope this has helped you when it comes to the charging process. I make my videos for my technicians to reference when they are in a bind out in the field. But if this can help anyone else, that’s great.
Thanks so much for reading, and we’ll see you on the next blog.
Expect Great Things at Your Fox Family Air Conditioning Tune-Up
What Is an Air Conditioner Tune-Up, Anyway?
An air conditioning tune-up is what responsible homeowners do to maintain their home’s HVAC system. It’s a thorough cleaning and testing of the air conditioning system, to ensure that it’ll work when you need it this summer. We operate with the understanding that a clean system will run longer than a dirty system. To read more about keeping your system running during the summer, check out our blog post on this topic.
Not every HVAC company in town will perform an Air conditioning tune-up. I would say it’s because they feel they’re not very good money generators for them. I get it, wiping down air conditioners and testing parts aren’t very exciting for some. But I don’t think they understand the opportunity they have to create a relationship with someone and their HVAC system.
I like to develop relationships with my customers by taking care of their AC system every spring. If we can perform an air conditioning tune-up every spring, for years and years, I know my customers will, at the very least, allow us to provide a quote for a new system when the time comes. At the same time, our customers get to work with Sacramento’s most honest air conditioning company. Our technicians will only bring up parts or repairs that will make the system return to factory standards, help it last longer, and make it safer for their families.
What Happens at My Air Conditoning Tune-Up?
When we are on the way, our technician will call you and let you know. We are proud to park on the street in our bright white vans with the Fox Family logo on them. After you open the door and allow us to come in, we usually start at the air filter and thermostat.
I like to ask if there are any areas of the house that need any attention. Do any rooms not get the right amount of air? Does it cool the house down to your satisfaction in the middle of summer? Questions like this can establish how you like your system to run. Because not every homeowner is the same, right?
Once I know what’s going on in your mind as a homeowner, we will turn on the AC system, together, at the thermostat, listen for the air to come on, and walk outside to make sure everything out there is at least running. Now we all know the system was running when we arrived!
From here, you’ll be able to sit back and do whatever you need to do while the tech goes out and runs through a list specifically designed for your type of air conditioning system.
Step One of Your Air Conditioning Tune-Up
We usually start out at the air handler in the attic or closet. As a responsible business owner, if the furnace is in the attic, I need my techs to get in and out quickly. It’s hard to ask a tech to spend time cleaning a furnace in a hot attic. The furnace gets physically cleaned during the furnace tune-up, rather than during an AC tune-up, but there are some really important things to check here, so we try to get in and get out effectively and safely.
The most important thing we’re testing is the temperature difference between your supply and return air ducts. If it’s not where it needs to be, we have a series of checks we will do to get it right. A quick look at the evaporator coil can make a huge difference in the comfort of your home this summer. If it’s dirty or clogged it will make your system underperform.
As part of the AC tune-up, we also need to make sure your blower and the flywheel is clean and ready to run a lot in the coming summer months. The tech will pour water down the drain lines to make sure the condensate drains properly.
We always offer the option of a condensate safety switch to protect your home from potential damage. The secondary drain pan under the evaporator coil in the attic is a potential source of problems as well, so we make sure it’s ready for any emergencies.
Additionally, we’ll make sure the metering device for your refrigeration system is mounted properly while checking for any obvious refrigerant leaks in the copper tubing. We’ll also check for proper insulation levels in your attic because it creates such an effective barrier between the hot air in the attic and the cool air you’re trying to keep in your house. It pays to have a thick layer of insulation up there!
Step Two of the Air Conditioning Tune-Up
Once we’re done in the attic — and I really only want my techs up there maybe fifteen minutes on warmer days — we’ll head to the outdoor unit where the majority of the AC tune-up is done. Here, we test the components inside the panel, focusing on things like your refrigerant levels to ensure your system isn’t running too long, unnecessarily. The high and low voltage electrical running the AC needs to maintain a certain sizing, workmanship, and integrity.
Checking Items During Your AC Tune-Up
All in all, we check about 35 items on the outdoor unit and 20 items on the indoor unit. If you happen to have a packaged unit that sits on the side of the house or even on the rooftop, we still check all 55 items.
After we check the entire AC system, we’ll let you know if there are any parts that need to be replaced. Our trucks are stocked with almost every part you need for your AC to get back up and running properly the same day.
If your system is running well, we get right to work washing your AC. Many air conditioning manufacturers are switching to materials like micro-channel which can’t be washed with soapy or chemical solutions, and we pay attention to things like that. If you have a dog that runs around in your back yard, we try not to use soapy solutions that drain into the area around the AC, so your best friend doesn’t get sick.
We are so thorough cleaning the AC, it’s not uncommon to see a tech vacuuming out your AC to get rid of the sticks and other debris that can be a nuisance to a healthy air conditioner.
What’s the Benefit of an AC Tune-Up?
When the air conditioning tune-up is complete, you’ll have peace of mind knowing that your system is in tip-top shape. Making sure a professional completes these steps every year will really pay off in the later years of your HVAC system’s life. As a technician, my 20-year-old system is so clean, it runs like a champ. It’s old and loud, but it keeps my house cool just fine! Even on 105-degree days. Why? Because I take care of it.
If you’re curious and would like to learn more about how your air conditioner works, check out my blog post on this topic.
So, give Fox Family a call here in the greater Sacramento Valley area. We would be honored to service your HVAC system in the year ahead!
Thanks for checking in on our blog. See you next week!
Don’t miss our video on this topic:
Good Customer Service or Good Technical Skills: Which is Better to Have?
Technical Skills Without Customer Service Can Be a Bad Mix and Vice Versa
Having both good customer service and good technical skills is super important. But if we had to decide one or the other when it comes to hiring a technician or having a technician come out to your house for service, which one would it be? I have my own opinion, and that’s what I’m going to share with you today.
Technical skills without customer service can be a bad mix and vice versa. Is professional customer service needed as much as your need to have a seasoned technician who lacks the social skills to be a lady or gentleman in your home while performing that service?
Is Good Customer Service Necessary?
Some people think customer service isn’t needed as much in the industrial or commercial sector because those technicians aren’t having to convince or deal with owners of the building right on the spot. Even if they did, most building owners and landlords aren’t concerned with anything but getting the repair made. They also want it at the lowest expense possible. They’re not concerned with how old the system is or the quality of the parts. Usually, they want to get as many years as possible out of their one system. To an extreme! I understand, though. It’s a business decision where quality isn’t as important as function in most cases.
Residential customers, on the other hand, are more connected to their HVAC system. They spend their hard-earned money on repairs and want their systems to last as long as possible, too. When those systems get to a certain age, usually 15 to 20 years old, they start thinking about changing out that system because quality and efficiency are much more important to them. Residential customers also feel more connected to their service technician and the company they represent. Relationships develop between company and customer.
Focusing on Customer Service
As our company grows and we are looking for our next technician to hire, this question comes up every time. Do we employ an experienced tech that might come in with deeply ingrained habits that might not line up with policies and procedures we have at Fox Family? Experienced techs that have always done it a certain way for years may not be focused on the customer service aspect.
What About Technical Skills?
On the other hand, should we hire a technician who we know has a great personality and necessary technical skills? This type of person is someone we can develop and mold into the kind of technician we want representing our company. It will take months, sometimes even a year, for that tech to get to the point where they can even go out on repair service calls. But, when it comes to deciding which technician to send into your home, it can be a tough decision.
My point is that some technically skilled people come into a company that may have worked for a shop that didn’t emphasize manners and common courtesies. I’m referring to things like wearing shoe covers, wiping down attic accesses when they come out of the attic, wearing face masks during COVID-19 in 2020, tucking in their shirts, being clean-shaven, etc. Things like these can make a difference when it comes to deciding whether or not I want that tech in our customer’s home.
A Better Tactic
A better tactic is to interview the most technically competent people available and, during subsequent interviews before hiring, work to discover the candidate’s collaborative abilities or willingness to learn such skills.
In talking about the relative importance of technical and people skills, it’s tough to suggest that one is more important than the other. I read somewhere that an opera is comprised of both words and music. It doesn’t work if either is missing. Similarly, technicians must have both technical and people skills to do their jobs successfully. Yes, technical skills come first. But people skills allow us to convince others of our ideas, to collaborate successfully, and to build successful long-term customer and coworker relationships.
Thanks so much for reading this week, and we’ll see you on the next blog.
Don’t Miss Our Videos Related to This Topic
Protecting Fox Family Customers and Employees During the Covid-19 Season
The steps we take to prevent the spread of the virus in the Sacramento Valley are essential to us and you
I’m sure tired of talking about it. It looks like there could even be another wave of it reemerging. COVID-19 has turned out to be the most diabolical event to happen in my lifetime. Restaurants and small businesses were the hardest hit. The heating and air conditioning industry also saw it’s share of technician layoffs and even closing shop until things get back to some sense of normalcy.
The spring season is when we typically spend a lot of our days running preventive maintenance calls. Pretty much all of our customers were telling us to stay home during the lockdown. It was a stressful time for everyone.
Fox Family had one technician on call every day during this time. That tech knew he could be called at any time to go on a service call. Everyone else stayed home to protect themselves. During that time, Melissa and I made sure our techs were still paid, and medical benefits were still intact. We were able to take advantage of the federal PPP fund. The Fund allowed us to take care of our techs, which, I’m sure, gave some relief to them during a solid two months off of work.
When May hit, the coronavirus started settling down across California. People started letting us into their homes. Our focus was not only to provide the same level of service to our loyal customers but to do so with extreme care. It became mandatory during this pandemic that we show up to the door of people’s homes with our facemask and our gloves on as well as the usual shoe covers we wear to protect their floors.
We’ve never before faced having to wear face masks and rubber gloves in people’s homes to make people feel safe. Wearing these PPE’s not only protected the customers but protected our tech’s loved ones when they got back home! But we immediately noticed customers appreciated this step taken by Fox Family Heating and Air. We always get great online customer reviews, but our latest reviews also mention the extra measures we’re taking to prevent the spread of the virus in our customer’s homes. It’s a great feeling to contribute to our community.
Fox Family will continue looking out for our customers during and after the COVID crisis rears its ugly head. The steps we take to prevent the spread of the virus are essential to us and to you. Our techs are looking forward to serving you in your home. You can feel safe knowing we are concerned for your safety as well.
Creating Consistent Service for Our Customers
Why Fox Family Service Calls Are All the Same
For the past few weeks, I’ve been working on standardizing the way we carry out our service calls. It’s really just good practice to have it written down for someone who might need to refer to it. It’s good to have a system for AC and heating service calls, but at the same time, we never want to take the personal aspect out of each call either. We hire our technicians for their personalities and train them to become great service technicians.
So how do we keep our service calls structured while still maintaining that family feel? At Fox Family Heating and Air, Melissa and I focus daily on treating our technicians great. We know that by treating them with the respect and kindness they deserve, they will take care of our customers the same way. We feel that goes a long way in reaching the goals of a structured service call while being personable at the same time.
It’s almost impossible to expect each service call to go the same way, every time. There are too many variables when it comes to residential and commercial HVAC services. Every customer’s concerns are unique to them.
But at the same time, if our customers refer us to their friends and family to service their HVAC systems, we want the flow of the call to be very similar from home to home and business to business. Our techs have a routine that includes:
- The Pre-Arrival
- Approaching the door
- Making Contact
- The Conversation
- The Diagnosis
- Making the Repairs
- Completing the Call
I can explain some of the aspects of our service call that should be standard from technician to technician in the hopes that no matter who comes out to service the HVAC system the total experience will be the same.
We always call our customers when we’re on the way. It’s nice to give our customers about a 15 to 30-minute heads up. It takes us off the clock for a customer who is expecting us.
The pre-arrival also includes us gathering ourselves after the drive to the job site. It’s important for a tech to leave the stresses of their day behind us. Traffic, other service calls, and life in general can make things tough for anyone.
At the arrival, we ensure our techs park on the street in front of the home or business. It’s important for us to not take our customers for granted in thinking we can just pull up in their driveway. Sometimes it’s necessary to park in the driveway, but we always get permission first.
Approaching the Door
On our approach to the home, we make sure not to walk across the lawn. Coming up the driveway or sidewalk is best for keeping the home clean once we get inside. We also only come to the front door. It’s just unorthodox to come to the side or back door to greet a customer. And, since everyone wants to feel like they’re the most important person on the technician’s mind at the time of arrival, talking or texting on the phone is avoided.
When we make contact with customers at the door, it’s important for us to be aware of certain things. Not everyone wants to shake hands with a technician when they arrive. We can be known to work on some dirty things during the day and people know that. But, if someone initiates a handshake, we always welcome it.
We also ask our customers if they’d like us to wear our shoe covers in the house to protect their floors. It’s also important for us to respect people’s homes and businesses by just focusing on the task at hand. We understand that people are private in their homes and everyone’s lifestyles are different. Making comments about cleanliness or particular items in the home is not what we do. So that sort of respect goes a long way with our customers, and they feel comfortable with us in their homes.
Having the Conversation
One thing I tell my techs is that we’ve heard our customer’s concerns a million times. They’re usually very similar from one customer to the next. But it’s important to Fox Family that we stop talking and listen to the customer’s concerns without interrupting. After they’re done telling us, we might ask some more specific questions to help us narrow down the problem, like:
- How long has it been happening?
- Has there been a power outage in your neighborhood lately? (brownouts, blackouts)
- Who does the preventive maintenance on your system?
- Any other history of problems with that unit?
We also want to learn about other areas of the home that might have problems going on. Perhaps there’s a room in a certain part of the house that’s warmer or cooler than the others, or they’re having air quality issues in the home, etc.
Along with those extra questions, we also like to ask “We’re always on the lookout for ways to make your system run better, last longer or be safer for you and your family. If I see something like that while I’m here, can I bring it to your attention?”
Some people say, “No” and that’s totally fine. We’ll get in and get out in a timely manner. But not asking puts us in a position where some customers might think we weren’t being thorough enough on the call to foresee these other problems.
Once we’ve figured out what’s going on with the system, we try to be as thorough as possible and let the customer know about any system problems we may have seen. For instance, the control board of a system might need to be replaced, but the capacitor for the blower motor (which is still working) is almost out of stored energy, which will prevent it from regulating the voltage to that motor.
The heat exchanger or firebox of the furnace keeps the spent gases in those hot chambers and flue pipe which then exhausts out of the rooftop. Let’s say you have a bad inducer motor which is preventing your system from running. Well, if the firebox of the furnace has failed, we feel like our customers would want to know since it involves their system running safely.
All in all, I just tell my techs to suggest all repairs needed as if it were their home’s HVAC system. We just want to bring the system back to manufacturer specs and keep the residents of that home safe. That particular home may need multiple repairs to get it back up and running in tip-top shape.
Another unique thing about Fox Family is that we want to protect the homeowner who may be using their house as a rental. One way we do this is by only talking to the owner about the repairs since they are the ones paying for it. The landlord/tenant relationship can be dicey at times. If we divulge repair information to the tenant but the owner decides not to make that repair, it can stir up the relationship which is not what we want to contribute to.
We understand that maybe only one repair can be made that day. Our customers’ budgets differ from one to another. We simply make the suggestions and do the work our customers approve.
Fox Family differentiates itself from other companies by offering a lifetime warranty on the parts we use to repair your system. This puts the responsibility on us to use the best products for your repair, which makes our customers feel better about the money they’re spending.
Making the Repairs
When making the repairs, we can usually go right out to our service truck and get the parts we need. Keeping our trucks stocked with all the right parts gets our customers heating or cooling again, quicker.
Sometimes a special part needs to be ordered and delivered to our shop. When the part comes in, we make the appointment to come back out and replace the part for the same price we agreed upon the first visit. Keeping the customer informed along the way during the delivery is another way we provide that personal touch with our customers.
After the repair, we clean up the service area and try to make it like we were never there. Hopefully, this will make the whole repair process go smoother for the customer.
Completing the Call
When it’s time to complete the call, we try to sit down at the kitchen table and go over everything we’ve done. We mention our lifetime warranty on the parts they’re paying for, and we offer to come out and perform the preventive maintenance on their system to help keep the system running as long as possible.
Our technicians are asked to collect the money for repairs they made that day, as billing can get very complicated for the office.
The only other thing I ask our techs to do is to make sure our customers know how much we appreciate them and to thank them for trusting us with their home’s HVAC system.
Having a standardized way of running a service call keeps every experience with a tech who comes to a customer’s home very similar. That way when we’re referred to friends and family, they get the same experience. All the personality and conversation during the rest of the call comes genuinely from our technicians. That’s why we hire our techs for their personalities and not so much their skills. Skills can be taught; a great personality can’t.
Thanks so much for stopping by and we’ll see you on the next blog.