What Happens During HVAC Maintenance and Tune-Ups?

What Happens During HVAC Maintenance and Tune-Ups?
Roger Bakies
Residential Sales Professional

I have been in the residential/light commercial HVAC business for 30 years. I grew up in a sheet metal fabrication shop and have installed, serviced, sold and helped people choose new systems to best fit their needs and lifestyle. I look forward to helping you pick the best fit for your home!

About This Article

Regular maintenance helps your HVAC system produce and distribute warm or cool air more evenly and steadily. But what are the steps your HVAC technician should be doing?

The average homeowner purchases only one or two HVAC systems in their lifetime. So how do you protect your investment, and how do you get the most out of your heating and cooling system?

You start by understanding that your investment needs care. Your heat pump, furnace, and/or air conditioner should run smoothly and efficiently during weather good and not, cold temperatures and hot. And they should run without you having to fret about how well they’re doing the job.

The worst-case scenario is that you skip recommended maintenance, and your HVAC gives out completely when the weather is at its worst.

It doesn’t have to be that way. At Fire & Ice, we offer tiers of maintenance plans designed to keep your HVAC humming along. We have been on thousands of service calls and want to educate you about what we do during these calls.

By the end of this article, you’ll know how each step of a tune-up can protect your system and peace of mind. You’ll also see some of the worst practices in the HVAC profession, each of which could mean the premature demise of an expensive piece of equipment.

Air Conditioner Maintenance Steps

AC tune-up checklist:

  • Lubricate all moving parts.
  • Install gauges, record pressures/temp.
  • Check air filter, replace if necessary.
  • Measure superheat to fine-tune refrigerant level.
  • Flush condensate drain to protect against overflow.
  • Clean the outdoor condenser coil.
  • Check blower motor (and belt if applicable).
  • Test temperature drop at return and supply air.
  • Safety test all controls for proper operation.
  • Amperage readings on all motors, test bearings.
  • Test operation and condition of compressor contacts.
  • Inspect capacitors and relays for rust and leaks.
  • Tighten and test all wires and connections.
  • Clean thermostat and confirm proper operation.
  • Turn humidifier off for summer non-operation.
  • Check outdoor disconnect (if applicable).
  •  Inform customer of equipment conditions.

The first thing you’re going to determine is if the system is operational and give it a once-over. Is the filter clean? Is the furnace working and functioning with the air conditioner and the entire system?

When I did maintenance, the first thing I did was turn everything on, make sure it’s running. Then I go outside and check the evaporator coil, whether it’s Trane’s Spine Fin or the conventional sheet tube, or “plate-fin,” as they call it.

If the liquid line is so hot you can barely hold your hand on it, there’s a pretty good chance that the condenser coil is dirty. If you’re going to do proper maintenance, frequently that coil will need to be cleaned.

Then you’re going to check things such as amp draws on the indoor motor, amp draws on the outdoor motor,  the bearings in the blower motor in the furnace, and check the contactor to see that it’s not pitted and it’s functioning properly.

You check the outdoor fan motor amp draw and the compressor amp draw and the outdoor condenser motor. You check the capacitor to make sure it’s within value, and check all the electrical connections to make sure you don’t have any bad connections.

Once you’ve done all that, you put your refrigerator manifold on, turn the unit on, give it five, 10 minutes, then check the refrigerant charge, and check the return and supply temperatures inside. You check the same thing outside to make sure that everything is within specs.

Most air conditioners don’t have a Weatherguard Top, and the base pan will get full of leaves and other debris. So you open that up and clean that out.

You clean the condenser coil. You’d be amazed at how much junk you can flush out.

Heat Pump Maintenance Steps

You would check everything that you did for an AC, plus you’re going to check the operation of the machine in heating mode (or cooling mode if you’re doing maintenance in the winter). You also check the function of the reversing valve and make sure the defrost cycle is working.

Furnace Maintenance Steps

Furnace tune-up steps:

  • Test for carbon monoxide.
  • Test for gas leaks up to furnace shut-off valve.
  • Check air filter, replace if necessary.
  • Check humidifier operation, change for winter operation.
  • Test and adjust the operation of safety and operating controls.
  • Inspect flue pipe and draft diverter.
  • Monitor for combustion leaks.
  • Test gas valve operation.
  • Check blower motor (and belt if applicable)
  • Test and tighten all wiring and connections.
  • Adjust burner for maximum efficiency.
  • Clean burners and inspect heat exchanger.
  • Clean and adjust the thermostat.
  • Lubricate all motors, bearings, fans, and circulators.
  • Clean and adjust pilot assembly.
  • Clean flame sensor.
  • Inform customer of equipment conditions.

Read more: Annual Tune-Up Service for Your Furnace

The first thing you do is ask if the homeowners have all the registers open. As part of the query, you want to get a cursory overview of the air distribution system and see if registers are closed, that there’s not a sofa or something against the wall blocking the return air.

With the furnace, you give it a once-over in terms of cleanliness. The inshot burners may need to be cleaned on a gas furnace. You check the amp draw on the blower motor, check the blower bearings, and the amp draw of the little inducer or draft motor to make sure that’s running properly.

You bring the furnace up to temperature, do a combustion analysis, and check a sample of the flue gas. Look for problems with the heat exchanger and the mixture of gases in there. You do a visual check of the heat exchanger and check the gas pressure.

You measure the temperature rise of the machine, which is the temperature of the return air coming to it versus the supply air leaving it. It’s supposed to be at a certain range. If it’s too hot, it’s running too high and you’re losing efficiency that could damage the heat exchanger. If it’s too low, you risk condensing in the heat exchanger, because you don’t have enough heat to get the flue products through without condensing.

You’re going to check all the safety devices. You pull the hose off the pressure switch. Make sure the port is clean where it goes into the heat exchanger. When the hose is off the pressure switch, the machine should shut down as a safety feature. You may want to disable the motor to see if the safety trips. On a condensing furnace, you’re going to flush the condensate system to make sure that’s draining properly.

I’ve seen it a hundred times where we went out and did the maintenance, then we go out there when it’s really cold, the furnace is running a lot and creating a lot of condensation and the homeowner is saying “It’s not keeping up with the thermometer.” Well, it’s easy to tell if the condensate trap is plugged. You clean out all the gunk and magically the furnace runs.

Furnace maintenance

What’s the Difference Between Maintenance and an Inspection?

Maintenance is the process of taking steps to maintain the machine. Inspection is, “Yep, that looks OK. Yep, that looks OK. No, that doesn’t look OK but I’m not doing anything with it.” I make a note of problems and relay them to the customer, but I’m not repairing anything. I’m just having a look.

I’m using just a flashlight and some diagnostic tools. We’re not cleaning the burners, we’re not adjusting the gas pressure, we’re not adjusting the blower speed for the heat rise.

When I’m checking out systems in the sales capacity, and the homeowner asks, “What do you think of the furnace?” “Well, it looks to be in average or above average condition for its age. If it works now, it might work for another ten minutes, or it might work for another ten years. I don’t know.” Only a proper maintenance visit can address that question.

Air conditioner maintenace with an HVAC technition

Common Steps Skipped by HVAC Technicians

If the refrigerant is low, an HVAC service person can recharge the system, but he doesn’t check for leaks. That should be mandatory. Is it ethical? Well, they can rationalize, “It’s not like I left him in an unsafe condition. It’s not easy to find leaks, which are very small.” At some point, the homeowner will need to add more refrigerant. Fire & Ice employees are paid hourly, not by the job. This ensures that they spend the time to find the leak, as opposed to others who are in a hurry to move on and make some more money elsewhere.

Another commonly skipped step is not cleaning the condenser coil. Getting a hose to the air conditioner or heat pump and finding a water source can be a pain, so it might not happen.

On gas furnaces, I’ll see people do a tune-up, and the burners are still dirty afterward. We always vacuum out the vestibule and the burner compartment and wipe things off.

The HVAC service person didn’t service the humidifier or dehumidifier, even though it’s part of the heating system.

I’d bet that during a good number of furnace tune-ups they don’t check the safety circuits, which involves disabling part of the machine to see if the circuit functions like it’s supposed to.

And we’ve gone on jobs many times where we’re just going to change the air conditioner, and the furnace is older. Well, when you pull the evaporator coil off of the top and you can physically look with your eyeballs down at the top of the heat exchanger and you see a gaping crack, you’re dealing with a furnace that’s been running for too long. But the customer says, “It works fine.” It’s a dangerous situation, but some homeowners don’t feel like paying for additional work.

We used to have to disable the heat exchanger for safety reasons. Now we turn the gas off, put a red tag on there, and tell the homeowner, “Don’t run it.” But we have customers who reply, “But it was running before he got here. We weren’t having headaches. The carbon monoxide alarm wasn’t going off. It’s cold out. I’m turning it on.” A furnace can have a crack in the heat exchanger and not emit much carbon monoxide. But when you’re talking about your family’s safety, is it worth that risk?

On a furnace, there are some new technicians who are like, “It’s working really great now, I’m not going to touch it.” They don’t want to make a mistake, so they do next to nothing. They don’t clean the condensate trap or the burners. To me, the big one is if they’re not checking the safety circuit, you should be fired and jailed, because this machine has the potential to kill you and burn your house down.

On the air conditioner, they don’t clean the evaporator coil or condenser coil. And the filter should always be checked. A dirty filter is both a health hazard and shortens the life of your HVAC.

HVAC maintenace

Choosing the Right Columbus HVAC Contractor

With so many options, it becomes difficult to choose the right HVAC contractor to perform maintenance on your system.

Cost is part of the overall equation, but the quality of the company you choose can save time, money, and hassle in the long run. Make sure you’re looking at the whole picture to make the best decision for you and your home.

Want to make sure you're holding your HVAC contractor to the highest standards? Click below to get our HVAC Contractor Checklist. It will give you 10 questions to ask during any estimate to make sure whoever you hire is prepared to do the job the right way.

HVAC Contractor Checklist

Read more:

Learn How Your Furnace Works
Fire & Ice Maintenance Agreements
HVAC Buyer’s Guide

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