It’s a hot Colorado afternoon, your AC is blowing warm air, and the house is heating up fast. Before you hit the panic button and pay for an emergency service call, check if a problem with your furnace could be the cause and take five minutes to run through this DIY checklist.
At Befort Plumbing & Heating, we find that nearly 20% of cooling calls in the Denver and Englewood area can be resolved with these simple steps.
1. Inspect Your AC Air Filter
A clogged air filter is the #1 cause of HVAC breakdowns. When the filter is caked in dust, the system can’t pull enough air through the coils, causing them to freeze into a block of ice.
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The Fix: If the filter looks gray or fuzzy, swap it out. If your unit has already frozen, turn the AC off but keep the fan on for 2–4 hours to let it thaw.
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Internal Link: If your system is still struggling after a filter change, it might be time for a professional AC Tune-Up.
2. Verify Thermostat Settings & Batteries
It sounds simple, but a “broken” AC is often just a thermostat communication issue.
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Check the Mode: Ensure it is set to Cool (not Heat or Fan Only).
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Batteries: If the screen is blank or fading, replace the batteries. A weak signal can prevent the thermostat from “talking” to your furnace or AC.
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Outbound Link: Learn more about efficient thermostat settings from Energy.gov to save on your monthly bills.
3. Flip the Breakers
HVAC systems pull a lot of power during a heatwave, which can occasionally trip a circuit breaker.
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The “Reset” Trick: Go to your electrical panel and find the breakers labeled “AC” or “Furnace.” Flip them all the way to OFF and then back to ON. Sometimes a tripped breaker stays in the middle and looks “On” when it’s actually disconnected.
4. Clear the Outdoor AC Condenser
Your outdoor unit needs to “breathe” to release the heat from your home.
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The Check: Ensure there are no weeds, fallen leaves, or “cottonwood” fuzz stuck to the silver fins. Clear a 2-foot perimeter around the unit.
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Outbound Link: See the ACCAs guide on outdoor unit maintenance for more tips on protecting your exterior equipment.
5. Check the “Float Switch” for Clogs
Most modern systems have a safety sensor in the condensate drain line. If the line gets clogged with algae or debris, the water backs up, triggers the “float switch,” and kills power to the system to prevent a flood in your home.
If you see standing water in the drain pan, you likely need a professional Drain Cleaning or a line flush to get the system running again.
Is your system still acting up after these steps? Don’t sweat it out. Our licensed technicians are ready to provide expert HVAC to get your home back to a comfortable temperature.
Give Befort Plumbing & Heating a call today at [303-366-2433].