WaterFurnace Error Codes: What They Mean — and What Not to Do

A WaterFurnace error code is your geothermal system’s way of saying, “Something needs attention.” Sometimes it is a simple airflow or drain issue. Other times, it points to refrigerant pressure, water flow, freeze protection, voltage, or sensor problems that should be handled by a trained geothermal technician.

EcoMech services WaterFurnace geothermal systems throughout the Atlanta area. If your WaterFurnace thermostat, Aurora control, or unit board is showing a fault, lockout, blinking light, or code, contact EcoMech for geothermal service at service@ecomech.net or call (678) 855-8140.

EcoMech is a WaterFurnace dealer for the Southeast and provides WaterFurnace geothermal installation, repairs, and service.

Quick Answer: Should You Reset a WaterFurnace Error Code?

Do not repeatedly reset your WaterFurnace system. A single reset may temporarily clear a fault, but repeated lockouts usually mean the system is protecting itself from damage.

Before calling for service, you can safely:

1. Write down the exact code or thermostat message.
2. Note whether the system is heating, cooling, or not running.
3. Check that the air filter is clean.
4. Make sure supply and return vents are not blocked.
5. Look for visible water around the unit or drain pan area.
6. Call EcoMech at (678) 855-8140 if the code returns.

Do not bypass safety switches, add refrigerant, jumper thermostat terminals, open electrical compartments, or keep power-cycling the system.

Why WaterFurnace Error Codes Matter

WaterFurnace geothermal systems use control boards and diagnostics to help protect the compressor, loop field, heat exchanger, blower, sensors, and electrical components.

Depending on your model, the problem may show up as a thermostat message, an Aurora AID tool message, a “lockout,” or a red LED flash code.

WaterFurnace Aurora documentation lists fault indicators such as HPS for high pressure, LPS for low pressure, FP1/FP2 for freeze detection, Condensate for overflow, O/U Voltage for over/under voltage, and Sensor Error for sensor-related issues.

That means the code is not just a random warning. It is a diagnostic clue. The goal is to find out why the fault happened before the system loses efficiency, shuts down again, or suffers expensive damage.

Common WaterFurnace Error Codes and What They Usually Mean

WaterFurnace codes can vary by model, thermostat, and control package, so always treat this as a general guide. EcoMech can verify the exact fault on-site.

WaterFurnace Aurora troubleshooting documentation identifies red LED flash codes for input fault, high pressure lockout, low pressure lockout, freeze detection, condensate overflow, over/under voltage, and freeze detection sensor error.

Code 2: High Pressure Fault

A high pressure fault usually means the system pressure has gone beyond the control’s safe operating range. WaterFurnace documentation notes that high pressure may be caused by low water flow in cooling or low airflow in heating, including dirty filters or coil buildup.

What homeowners can check:

• Is the filter dirty or overdue?
• Are return grilles blocked?
• Are supply vents closed?
• Did the fault happen during heavy cooling or heating demand?

What not to do:

• Do not keep resetting the unit.
• Do not open refrigerant lines.
• Do not assume the system just “needs Freon.”
• Do not bypass the pressure safety.

A high pressure fault can involve airflow, water flow, refrigerant, sensor, or heat exchanger conditions. EcoMech can test the system properly and identify the real cause.

Need WaterFurnace high pressure fault service? Call EcoMech at (678) 855-8140.

Code 3: Low Pressure Fault

A low pressure fault can be more serious than it sounds. WaterFurnace documentation states that a low pressure switch opening may indicate refrigerant charge loss, restriction, or a frozen heat exchanger.

What homeowners should not do:

• Do not add refrigerant.
• Do not use leak-seal products.
• Do not thaw or heat internal components.
• Do not keep forcing the system to run.

A geothermal technician needs to check the refrigeration circuit, water flow, sensors, and operating conditions. If the system is low on refrigerant, the leak must be found and repaired before the system is properly recharged.

For WaterFurnace low pressure lockouts in Atlanta, email service@ecomech.net or call (678) 855-8140.

Codes 4 and 5: Freeze Detection Faults

Freeze detection faults are designed to protect the heat exchanger and loop system. On many Aurora controls, FP1 and FP2 relate to freeze detection sensors. WaterFurnace documentation associates freeze detection faults with low or no water flow, low system charge, TXV issues, antifreeze composition, or water flow conditions through the heat exchanger.

This is especially important on geothermal systems because water flow and heat transfer are central to system performance. A freeze protection lockout is not something to ignore.

Do not:

• Disable freeze protection.
• Bypass the sensor.
• Run the unit repeatedly after lockout.
• Guess at loop fluid or antifreeze issues.

Call EcoMech so a geothermal technician can check loop flow, pump operation, temperature split, sensors, refrigerant performance, and control history.

Code 7: Condensate Overflow Fault

A condensate fault usually means water has collected where it should not. WaterFurnace documentation describes this as condensate water in the drain pan touching the sensor terminal and recommends checking that the drain line is clear and properly pitched.

For homeowners, this code matters because it can turn into water damage if ignored.

You can safely look for:

• Water around the unit.
• A clogged or backed-up drain line.
• A full drain pan.
• Signs of overflow near finished areas.

Do not remove wires, tape sensors, or bypass the condensate safety. The safety exists to stop the system before water damage gets worse.

Seeing a condensate fault on your WaterFurnace? Call EcoMech at (678) 855-8140 before it becomes a cleanup problem.

Code 8: Over/Under Voltage Fault

An over/under voltage fault means the WaterFurnace control has detected voltage outside its expected range. This may involve the control transformer, incoming power, low-voltage wiring, or power quality.

Do not keep flipping breakers or power-cycling the system. Electrical faults can damage controls and create safety risks. If the code returns, schedule service.

What to Tell EcoMech When You Call

To speed up your WaterFurnace service visit, send or have this information ready:

• The exact error code or thermostat message.
• A photo of the thermostat or fault screen.
• Whether the system was heating, cooling, or idle.
• Whether the unit is in lockout.
• How many times the code has appeared.
• Any recent filter changes, power outages, or maintenance.
• The model and serial number if accessible.
• Any water around the unit or drain area.

Email photos and service details to service@ecomech.net, or call (678) 855-8140.

What Not to Do When Your WaterFurnace Shows an Error Code

Here is the most important part: WaterFurnace fault codes are not DIY repair instructions.

Avoid these common mistakes:

1. 1. Do Not Keep Resetting the System
      Repeated resets can hide the real problem and allow the system to keep running under unsafe conditions.
   2. Do Not Bypass Safety Controls
      Pressure switches, freeze sensors, condensate switches, and voltage protections are there to prevent expensive damage.
   3. Do Not Add Refrigerant Yourself
      Low pressure does not always mean “just add refrigerant.” The system may have a leak, restriction, sensor issue, or water flow problem.
   4. Do Not Ignore Water Around the Unit
      A condensate issue can damage floors, ceilings, walls, and mechanical spaces.
   5. Do Not Wait Until the System Fully Fails
      A fault code is often an early warning. Scheduling service quickly can prevent bigger repairs and longer downtime.

Schedule WaterFurnace Geothermal Service in Atlanta

If your WaterFurnace geothermal system is showing an error code, blinking red light, lockout message, high pressure fault, low pressure fault, freeze detection fault, or condensate warning, EcoMech can help.

EcoMech services geothermal systems across Atlanta and surrounding Georgia communities, including areas such as Atlanta, Buckhead, Decatur, Dunwoody, East Cobb, Fayetteville, Milton, Newnan, Peachtree City, Roswell, Sandy Springs, Smyrna, Vinings, Woodstock, and more.

Do not let a WaterFurnace error code turn into a no-heat, no-cooling, water damage, or compressor problem. Schedule geothermal service with EcoMech today.

FAQ Section

What does a WaterFurnace lockout mean?

A lockout means the system control has stopped operation because it detected a fault. This protects the equipment from continuing to run under unsafe or damaging conditions.

Can I reset my WaterFurnace geothermal system?

A single reset may clear a temporary fault, but repeated resets are a warning sign. If the code returns, stop resetting and call EcoMech at (678) 855-8140.

What does WaterFurnace Code 2 mean?

Code 2 is commonly associated with a high pressure fault. It may involve water flow, airflow, refrigerant conditions, dirty filters, coil issues, or controls.

What does WaterFurnace Code 3 mean?

Code 3 is commonly associated with a low pressure fault. It may indicate refrigerant loss, system restriction, frozen heat exchanger, or related diagnostics that require a trained technician.

What does a WaterFurnace condensate fault mean?

A condensate fault usually means water is present in the drain pan or drain safety area. Schedule service quickly to reduce the risk of water damage.

Who services WaterFurnace geothermal systems in Atlanta?

EcoMech services WaterFurnace geothermal systems in Atlanta and surrounding Georgia service areas. Call (678) 855-8140 or email service@ecomech.net.