Rooftop Unit Troubleshooting Tips
If you’re standing on a step stool, peering into the vents and scratching your head wondering why on earth the inside of your building is the same temperature as the 90-degree weather outside, there could be something wrong with your rooftop unit. In this guide, we’ll provide some potential rooftop unit troubleshooting tips to diagnose the issue quickly.
Not Working or Poor Airflow
There are several reasons why your RTU might be turning on and off unexpectedly or won’t turn on altogether. If you’re having electrical troubles, check out some rooftop unit troubleshooting tips to help you restore power:
- Circuit breaker is off or tripped - Check that the circuit breaker is on and reset it if it’s tripped.
- Air filters are dirty or damaged - Worn out or dirty air filters can make it hard for cool or warm air to circulate. Make sure to routinely clean or replace them to keep your HVAC equipment running efficiently.
- Dirty Evaporator & Condenser Coils - To prevent the reduced efficiency and poor indoor air quality caused by dirty coils, it’s important to schedule biannual checkups with your HVAC service technician, who will conduct regular cleaning as per their maintenance checklist.
- Thermostat is on the wrong setting - Switch to COOL or HEAT.
- Thermostat temperature is set too high or low - Adjust the temperature to a desired setting.
- Returns are dirty - Dust or vacuum the returns.
- Faulty Electrical Connection - Faulty electrical connections can occur upon installation or later down the line due to normal wear and tear. Contact an authorized service technician to remedy this.
- Drainage Issues - If your unit doesn’t receive regular maintenance, the drain line or condensate pan can become backed up or clogged with dirt, debris, algae or mold. Contact a technician to remedy this issue.
- Extreme Weather - If there’s a storm raging outside your window or you're currently experiencing record highs and your AC has just turned off, the two are likely related. Power surges caused by lightning strikes, downed power lines, hail damage and extreme heat can all cause your rooftop unit to turn off.
- Blocked Ductwork - If it’s been a while since you’ve changed the air filters or had an HVAC technician look at your RTU, you might be dealing with a severe case of blocked ductwork. Contact a technician to fix this.
Noises
Mechanical machinery is known to make a twang or two on initial startup or when it switches between heating and cooling sequences. That said, if it starts to sound like someone is banging on the pipes with a wrench or you notice other unusual noises like squealing, rattling or whistling, it’s time to give your best friend, the HVAC technician, a ring.
Whistling
- Air filters are dirty or damaged - Make sure to routinely clean or replace them to keep your HVAC equipment running efficiently.
- Belts are worn out - Contact a technician to replace and tension them.
- Returns are dirty - Dust or vacuum the returns.
Semi-Loud Buzzing
This sound will often occur when the unit starts running. So if you just turned on the thermostat and you’re hearing a semi-loud buzzing, there may not be an issue occurring. However, If the sound is louder than usual or happening more randomly, contact an authorized service technician to investigate.