Aerco Water Heater Is Not Heating: Here's How to Fix It

Aerco Water Heater Is Not Heating: Here's How to Fix It

Aerco water heaters are known for their reliability, high efficiency, and advanced design. But much like any mechanical system, they occasionally have problems. One of the most frustrating problems users encounter is when their water heater is not heating properly—or not at all.

Whether you’re a facility manager, maintenance technician, or property owner, understanding the root causes and solutions to a heating issue can save time, money, and inconvenience. In this guide, we’ll explore the common reasons your Aerco water heater is not heating and walk you through professional fixes.

Common Reasons Your Aerco Water Heater Is Not Heating and Fixes

Most heating failures result from identifiable issues that can be diagnosed with a step-by-step approach. Below, we explore the most frequent causes behind a non-heating Aerco water heater, along with practical fixes you can apply—either independently or with the help of a trained professional.

Power Supply Issues

A lack of electrical power is often the first and most obvious culprit when the water heater is unresponsive.

Symptoms: The display screen is blank, no startup sound is heard, or the unit does not respond to inputs.

How to Fix It:

• Check the breaker panel. Ensure the dedicated circuit breaker for the water heater has not tripped. If it has, reset it and monitor for recurrence.

• Inspect the power switch. Confirm that the heater’s power switch is in the ON position and not accidentally turned off.

• Examine wiring connections. Over time, vibrations can loosen wires, or corrosion can cause disconnections. If any wiring issues are visible—or if the wiring seems aged—contact a licensed electrician or HVAC technician to inspect and repair.

• Check internal fuses. Some water heater models come with internal fuses. If the unit doesn’t power on, check these fuses and replace any that are blown. You can find compatible fuses and other Aerco water heater parts through authorized suppliers.

  
  

Faulty Ignition System

For the heater to function, the ignition system is essential. If the burner doesn’t ignite, no heat will be produced—even if the rest of the system seems operational.

Symptoms: Clicking sounds without ignition, visible error codes, or failure to start the heating cycle.

How to Fix It:

• Clean the ignition sensor. Over time, carbon buildup can block signal transmission. Gently clean the sensor tip using a fine emery cloth or a soft brush.

• Reset the control panel. Sometimes, the ignition system can fail temporarily and may recover after a full reset.

• Replace ignition components. The ignition module or flame sensor may be faulty and need to be replaced if cleaning doesn't resolve the issue. Always use genuine Aerco water heater parts for compatibility and safety.

  
  

Gas Supply Interruption

An Aerco water heater powered by natural gas or propane depends on a consistent fuel supply. Any disruption will prevent the burner from igniting.

Symptoms: The unit cycles through startup but never ignites, or there’s a gas-related error code.

How to Fix It:

• Ensure the gas valve is open. Sometimes, during maintenance or inspections, the main gas valve may be closed or partially shut. Open it fully.

• Inspect for leaks or disconnections. Carefully examine gas line fittings for signs of wear or leaks. Use soapy water to check for bubbling that indicates a leak.

• Check other appliances. Confirm that other gas appliances in the building are working, ruling out a larger gas supply issue.

• Contact your gas provider. In cases of a suspected utility failure or scheduled outage, reach out to your gas company. If the issue requires replacing regulators or valves, ensure you’re sourcing OEM water heater parts for the repair.

  
  

Incorrect Temperature Setpoint

The water heater may be operating perfectly but set to a temperature too low to meet demand, giving the impression it isn’t heating.

Symptoms: Lukewarm water or water that hasn't heated up much.

How to Fix It:

• Access the control panel. Navigate to the temperature settings and check the current setpoint.

• Adjust the setpoint. In most commercial settings, water should be set to 120°F to 140°F. Adjust accordingly based on usage needs.

• Watch for overrides. Building management systems may override local control. Consult your facilities team or check external system settings. If any hardware needs to be updated, ensure you install compatible Aerco water heater parts to maintain safe operation.

  
  

Blocked or Dirty Heat Exchanger

Over time, minerals in the water can accumulate inside the heat exchanger, reducing efficiency or blocking heat transfer entirely.

Symptoms: Reduced water temperature, longer heat-up times, or system lockouts.

How to Fix It:

• Descale the system. Aerco recommends descaling every 6–12 months using approved descaling agents and a circulating pump.

• Flush the system. Use the integrated flushing valves to rinse debris from the heat exchanger.

• Professional cleaning. If buildup is severe, a licensed technician can perform a chemical or mechanical cleaning. Replacing compromised components with genuine Aerco water heater parts may be necessary for long-term performance.

  
  

Faulty Temperature Sensors or Thermistors

Temperature sensors (inlet, outlet, or flue) are vital for accurate control. A failed sensor can cause erratic readings or shut down the unit to prevent damage.

Symptoms: Error codes, inconsistent water temperatures, or failure to complete a heating cycle.

How to Fix It:

• Read error codes. The digital display on the water heater typically shows a fault code when a sensor fails.

• Use a multimeter. Test the resistance of the suspected thermistor. Values that are out of spec suggest sensor failure.

• Replace faulty sensors. Install OEM Aerco water heater parts to restore proper function and calibration.

  
  

Water Flow Problems

Adequate water flow is essential. A drop in flow below the minimum threshold will prevent the unit from starting or lead to overheating.

Symptoms: Error codes, system lockouts, or low hot water pressure.

How to Fix It:

• Check inlet filters. Filters can become clogged with sediment, restricting flow. Clean or replace them as needed.

• Inspect water pumps. If the feedwater or recirculation pump is malfunctioning, flow will suffer. Ensure the pump is operational and properly sized.

• Evaluate flow sensors. A faulty sensor may fail to detect flow, even if water is moving. Replace with appropriate Aerco water heater parts if necessary.

  
  

Control Panel Lockout or Error Codes

Aerco water heaters have built-in safety protocols that shut the unit down in case of repeated ignition failures, overheating, or sensor errors.

Symptoms: Display shows lockout status or flashing fault codes.

How to Fix It:

• Read the error code. Each Aerco model uses a code system to identify faults. Refer to the owner’s manual for interpretation.

• Reset the system. After addressing the issue, reset the unit by holding the reset button or power cycling the heater.

• Firmware updates. Aerco occasionally releases firmware to address bugs or improve performance. Check with technical support for updates. If the control board itself is defective, it should be replaced with certified Aerco water heater parts to avoid system incompatibilities.

  
  

Combustion Air Blockages

Proper air intake and exhaust venting are essential for combustion. Blockages in these pathways can shut the unit down as a safety measure.

Symptoms: Ignition failure, overheating, or exhaust-related error codes.

How to Fix It:

• Clear air intake filters. Remove debris, dust, or insects that may be clogging intake screens.

• Inspect the flue and venting. Ensure the exhaust system is free of bird nests, leaves, snow, or ice.

• Check the blower fan. If the combustion fan isn’t running or is underperforming, the burner will not ignite. Replace the fan with authentic Aerco water heater parts to ensure optimal airflow and combustion.

  
  

Control System Misconfiguration

Advanced water heaters are equipped with programmable logic controls. Incorrect settings can prevent operation even if all hardware is functional.

Symptoms: No startup, incorrect cycling, or strange behavior without physical faults.

How to Fix It:

• Review configuration parameters. Access the technician-level menu (if available) and verify all settings.

• Restore default settings. If the configuration has been altered incorrectly, a factory reset may be needed.

• Consult technical support. Aerco’s support line can help interpret settings or guide you through configuration recovery.

When your Aerco water heater is not heating, it can bring essential operations to a halt. Fortunately, most issues stem from manageable causes—whether it's an ignition fault, power supply disruption, or sensor failure. By following the troubleshooting steps outlined above, you can often diagnose and fix the problem yourself or know exactly when to call for expert help. The water heater remains a top choice for commercial water heating systems, but like any sophisticated machine, it demands attention and care. Regular maintenance, quality replacements using certified Aerco water heater parts, and prompt action at the first sign of trouble will extend its life and performance—keeping your facility running smoothly.

Written by Allen Rode for PartsHnC, your trusted source for high-quality HVAC parts, including water heater components, air conditioner parts, and heat pump solutions.