A. O. Smith · Voltex MAX / Signature 900 Premium (HPTA, HPA10)
A. O. Smith Voltex MAX / Signature 900 Premium (HPTA, HPA10) error code 006
Internal Processor Error
What it means
Internal Processor Error - Frequency Fault - Standard AD Reference Fault - Non-Volatile Memory Fault - Crystal Fault.
How it shows: with an alert icon flashing (also flashing red LED and beeper)
What A. O. Smith says to do
These steps involve electrical testing or parts replacement. A. O. Smith's manuals tell owners to leave that work to a qualified service technician.
1. Turn OFF electrical power at the breaker. Now turn ON electrical power to see if error clears. If error has not cleared, turn OFF electrical power at the breaker and replace the Control Assembly. 2. Turn ON electrical power at breaker.
The manual adds: "These instructions are brief and intended as guidance for a qualified person. If you lack the necessary skills to perform these procedures call the Technical Assistance Hotline which is listed on the water heater's warranty sheet for assistance." (Hybrid Electric Heat Pump Water Heater Installation Instructions and Use & Care Guide (Premium/Smart Valve), 100379654_2000812401, page 27)
Last checked 2026-10-03.
Safety first
- WARNING! Working near an energized circuit can result in severe injury or death from electrical shock. (p.28)
- WARNING! When you are finished, be sure all covers are secured to reduce the risk of fire and electric shock. (p.28)
From the manufacturer's manual for this series.
The same code on other models
Codes mean different things on different heaters. Match the series to the model number on your rating label.
- A. O. Smith Voltex AL Smart / Signature 900 Standard (HPTS, HPS10): 006
- A. O. Smith Voltex 120V plug-in (HPTV, HPV10): 006
Other Voltex MAX / Signature 900 Premium (HPTA, HPA10) codes
- 001 (Dry-fire)
- 003 (Upper thermistor sensor failure)
- 004 (Lower thermistor sensor failure)
- 009 (Power supply voltage too low)
- 021 (Upper element circuit failure)
- 022 (Lower element circuit failure)
- 025 (Heat pump coil temperature sensor)
- 026 (Heat pump suction temperature sensor)
- 027 (Heat pump discharge temperature sensor)
- 028 (Ambient temperature sensor failure)
- 029 (Outlet temperature sensor failure)
- 031 (Water leak)
- 044 (SAC anode depleted)
- 046 (Shut-off valve)
- 047 (Smart Valve failure)
- 048 (Battery low energy)
- 080 (Air filter dirty)
- 081 (Condensate management)
- 083 (Compressor suction pressure too low)
- 084 (Compressor not functioning)
- 085 (Compressor discharge temperature too high)
- 086 (Fan speed feedback)
- HPO (Heat pump out of operating range)
- ICE (Heat pump defrost)
- CLR (Error code cleared)