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Appliance Error Codes

HP5 Error on AO-SMITH HPTU-50N Heat Pump Water Heater — Fix Guide

Error HP5 on ao-smith : Evaporator (refrigerant) temperature sensor fault. Follow the troubleshooting steps below to diagnose and fix this heat-pump-water-heater issue. ## What Error Code HP5 Means on a ao-smith HPTU-50N Error HP5 on the HPTU-50N indicates the evaporator refrigerant temperature sensor is faulty. This sensor is used for defrost control and compressor protection in cold ambient conditions. When HP5 appears, the ao-smith heat pump water heater pauses normal operation to protect internal components from potential damage. Not every HP5 fault requires a professional engineer — many are resolved through careful inspection and routine maintenance. Work through each diagnostic step below in sequence, starting with the simplest check, to identify the root cause efficiently before considering part replacement or arranging a service call. ## Symptoms - HP5 on display; heat pump mode disabled

  • Defrost cycle may not activate correctly
  • Ice buildup on evaporator coil possible ## Common Causes - Evaporator (refrigerant) temperature sensor fault ## Tools You May Need - Multimeter
  • Replacement evaporator thermistor ## Step-by-Step Repair Guide | Step | Action | Result | |------|--------|--------| | 1 | Power off the unit. | Done — continue to step 2 if the issue persists. | | 2 | Access the evaporator compartment and locate the refrigerant temperature sensor clipped to the coil. | Done — continue to step 3 if the issue persists. | | 3 | Measure resistance and compare to specification. | Done — continue to step 4 if the issue persists. | | 4 | Replace if faulty; ensure the replacement is seated in the original position on the coil. | Done — continue to step 5 if the issue persists. | | 5 | Restore power and confirm HP5 is cleared. | Done — if the fault remains, contact a qualified technician. | ## Safety Precautions Disconnect power before accessing the evaporator compartment. ## Estimated Repair Time and Difficulty Most heat pump water heater error code HP5 faults can be assessed and addressed in 30–90 minutes using the steps above. The diagnostic process requires only basic tools: a multimeter and standard screwdrivers cover the majority of checks described here. If a replacement part is required, allow 1–5 working days for delivery. A trained technician with access to the correct diagnostic equipment will typically resolve this type of fault within a single service visit. ## When to Call a Technician Contact a ao-smith authorised service technician if: the fault persists after following all the steps above; if PCB-level or refrigerant-circuit work is required; or if you are not comfortable working with electrical or mechanical components. When calling, have the full model number, the error code displayed, and a brief description of any sounds or symptoms you noticed before the fault appeared — this helps the technician prepare the correct parts and tools. ## Frequently Asked Questions Q: Does HP5 affect my hot water supply? HP5 disables heat pump mode, but electric backup heating continues to work, so hot water supply is maintained — just at higher operating cost. ### Is it safe to keep using my ao-smith with error HP5? If error HP5 does not indicate an immediate safety hazard such as a gas leak, electrical short, or water flooding, you can continue limited use while monitoring the appliance. However, running the heat-pump-water-heater with an active error code increases the risk of further damage. Address the underlying issue as soon as possible. For high-severity errors, disconnect the appliance and contact a qualified technician. ### How much does it cost to fix error HP5 on a ao-smith ? Repair costs for error HP5 on the ao-smith heat-pump-water-heater depend on the root cause. DIY fixes such as cleaning filters, resetting the unit, or reconnecting loose wires cost nothing beyond basic tools. If a component replacement is needed, parts and labor from a certified technician are the main expenses. Contact a ao-smith-authorized service provider for an accurate estimate based on your specific situation. ### What does error code HP5 mean on a ao-smith heat-pump-water-heater? Error code HP5 on ao-smith heat-pump-water-heater models indicates Evaporator (refrigerant) temperature sensor fault. This error is detected by the appliance’s internal diagnostic system and displayed to alert the user that attention is needed. Refer to the troubleshooting steps above for guidance on resolving this issue. ### Is it safe to keep using my ao-smith with error HP5? If error HP5 does not indicate an immediate safety hazard such as a gas leak, electrical short, or water flooding, you can continue limited use while monitoring the appliance. However, running the heat-pump-water-heater with an active error code increases the risk of further damage. Address the underlying issue as soon as possible. For high-severity errors, disconnect the appliance and contact a qualified technician. ### How much does it cost to fix error HP5 on a ao-smith ? Repair costs for error HP5 on the ao-smith heat-pump-water-heater depend on the root cause. DIY fixes such as cleaning filters, resetting the unit, or reconnecting loose wires cost nothing beyond basic tools. If a component replacement is needed, parts and labor from a certified technician are the main expenses. Contact a ao-smith-authorized service provider for an accurate estimate based on your specific situation. ### What does error code HP5 mean on a ao-smith heat-pump-water-heater? Error code HP5 on ao-smith heat-pump-water-heater models indicates Evaporator (refrigerant) temperature sensor fault. This error is detected by the appliance’s internal diagnostic system and displayed to alert the user that attention is needed. Refer to the troubleshooting steps above for guidance on resolving this issue.