Hot Summer Days and a Dirty Evaporator Coil Mean Big Headaches



It is every building owner’s worst nightmare in the dead of summer. It is 98 degrees outside and your phone starts ringing…  and ringing…  and ringing. During the hot summer months your building’s air conditioning system becomes the lifeblood of your facility. If your A/C goes down completely, or even if just has a day that it can’t keep up with the heat well, your phone is going to start to ring off the hook and it won’t stop until you fix the problem…  or until the Fall…  whichever comes first! When your air conditioner suddenly stops performing correctly, it could definitely be cause for alarm or sometimes it can be a simple fix; something as simple as a popped circuit breaker…  or a little dirt. As a water treatment service provider specializing in boiler water treatment, cooling tower water treatment, and HVAC cleaning services, we see a lot preventable issues with commercial HVAC units.

The most common cause of air conditioner problems is dirty coils. Whether it is dirt in the outside condenser coils or a dirty evaporator coil in the indoor unit, dust and dirt will gradually impede your air conditioning units’ capability to produce adequate cooling.

Proper air conditioner maintenance should be an integral part of any building manager’s priority list. Part of that checklist should be an appropriate filter replacement schedule, proper vent and air duct cleaning schedule, and a proper coil cleaning service program. Usually, a good air conditioning cleaning service in your area can provide you with a HVAC Cleaning and Maintenance Contract that can be purchased yearly or seasonally.

Here are the most typical problems that arise with basic commercial HVAC systems:

My Air Condition Won’t Turn On

Check Your ThermostatIf your air conditioner just won’t turn on, you should probably check your circuit breakers first. A tripped circuit breaker is not uncommon. Also, check your indoor thermostat; if it operates off of batteries, make sure you replace them before calling a technician. That tip can save you an embarrassing and expensive service visit. There is nothing worse than an air conditioning tech charging you $500 to replace three double-A batteries. Also, double check your thermostat settings. Sometimes a tenant can accidently move the switch from COOL to HEAT. Also try dropping the temperature set point on the thermostat by more than 10 degrees and see if that makes your air conditioning unit switch on. If that does the trick, you could have a bad or poorly calibrated thermostat.

If these tips do not get your air conditioning unit to turn on, it’s time to call your air conditioning service provider. It could be a short in the system, a blown motor or a host of other issues that you will need a professional to assess and repair.

My Air Conditioner is On, But it is Blowing Out Warm Air

Sometimes your air conditioning unit will turn on, but warm air will come out of the vents. After checking that your thermostat is properly set to a lower temperature, you are going to want to check your coils. The outside condenser coils are easy to check. They are located inside the outside condenser unit. Many models have a fan that pulls air up through the coil. First check to see if that fan is on. If it isn’t, something is wrong and you need to contact a technician. If the fan is on, however, you should examine the air intake areas for debris.

Best HVAC Service in New York CityMany times there is something preventing adequate air flow through the condenser coil. This can be caused by plant growth around the outside unit, or actual dirt and dust on the coil, or something as simple as a plastic bag that sucked into the air intake. We find plastic bags stuck to the outside of condenser units all the time, especially in highly trafficked urban areas like New York City.

If your outside coil looks clean and free from obstruction, then you may have an issue with your inside evaporator coil. These coils are generally harder to get to unless your system was designed to give you easy access. One common way to determine if you inside evaporator coil is not getting proper air flow is to check the inside air intake filters. If your filters are dirty, it could easily impede air flow to the point of diminishing cooling capabilities. The easy fix: Change your filter. Restricted air flow over the evaporator coil can eventually cause the coil to freeze.

IMPORTANT NOTE: Sometimes you will check your air intake and find that there is no filter in place. This could be a bad sign. If someone forgot to install or replace the air filter that means that dust and debris could have easily accumulated on your evaporator coil. In this case, you may need the help of a commercial HVAC cleaning company.

Another tell-tale way to determine if your evaporator coil in freezing up is to evaluate what is happening when you first turn on your air conditioning system. If your system produces cooling for a short time, but then quickly starts to blow out warm air, you may have a frozen evaporator coil. Typically, if you turn off the system the ice buildup on the coil will melt and when you turn the system back on it will produce cooling again for a short time until it freezes again.

If you have determined that your filters are clean and properly installed, then you could have an issue with your refrigerant, in which case you will need to contact an air conditioning service provider.

My Air Conditioner is On, But it is NOT Cooling Very Well

If your air conditioner system is on and the thermostat is set properly but it is still not cooling your building, you may have issues with dirty coils and or filters. However, you should know the basic principles of how air conditioning works and what your system can do even in the best of circumstances. For instance, most commercial package air conditioning systems should be able to maintain between 20 and 30 degrees difference between the indoor and outdoor temperatures, but not much more than that. So if your tenants are complaining that 75 degrees is still too warm on a 100+ day, there unfortunately is not much more that you are going to be able to do for them.

If your air conditioner still can’t keep up on a moderately hot day, you may have a problem with dirt on your coils, a refrigeration leak, lack of air flow due to a dirty filter or a frozen evaporator coil. If you suspect that this is an issue, make the call sooner than later, air conditioning problem typically do not “work themselves out.” On the contrary, they just tend to get worse.

If you need help cleaning your commercial HVAC equipment, please check out our menu of HVAC Cleaning Services below.

Thanks for reading!

About Clarity Water Technologies

Clarity Water Technologies is the leading industrial and commercial water treatment company, providing expert consulting and cutting-edge chemistry for your facility’s heating, cooling, potable and process applications.

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About the Clarity Blog

Clarity’s Water Treatment blog is written to provide tips and helpful information to anyone who is involved in managing a water treatment application at a facility. 

Our water treatment experts are here to help, no matter what your facility’s heating, cooling, potable or process application may be.  Check our blog for articles on topics like boiler and cooling water, cooling tower cleaning, legionella prevention and remediation, and environmentally-friendly water treatment options.

Clarity Water Technologies is the leading industrial and commercial water treatment company in the U.S.

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