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Appliance Error Codes

C2 Error on Rheem RTGH-95DVLN Tankless Water Heater — Fix Guide

Error C2 on Rheem : No ignition — flame not detected after trial for ignition. Follow the troubleshooting steps below to diagnose and fix this tankless-water-heater issue. ## What Error Code C2 Means on a Rheem RTGH-95DVLN Error C2 on the RTGH-95DVLN tankless unit means the burner failed to establish a flame within the 5-second ignition trial period. This triggers an automatic lockout requiring manual reset. When C2 appears, the Rheem tankless water heater pauses normal operation to protect internal components from potential damage. Not every C2 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 - Hot water demand starts but unit does not fire

  • C2 on display; unit goes into lockout
  • Igniter clicking heard but no sustained flame
  • Unit resets but C2 returns immediately ## Common Causes - No ignition — flame not detected after trial for ignition ## Tools You May Need - Gas pressure gauge
  • Flashlight
  • Screwdrivers ## Step-by-Step Repair Guide | Step | Action | Result | |------|--------|--------| | 1 | Check the gas supply pressure at the unit — Rheem tankless units require minimum 5 in. WC (water column) for natural gas, 11 in. WC for propane at full fire. | Done — continue to step 2 if the issue persists. | | 2 | Ensure the gas valve is fully open and the supply line shutoff is on. | Done — continue to step 3 if the issue persists. | | 3 | Inspect the igniter electrodes for carbon buildup or cracking; clean with a soft brush. | Done — continue to step 4 if the issue persists. | | 4 | Check the flame sensor rod for fouling; clean with fine steel wool. | Done — continue to step 5 if the issue persists. | | 5 | If gas pressure and ignition components are within specification, the gas valve or control board is faulty. | Done — if the fault remains, contact a qualified technician. | ## Safety Precautions Do not reset C2 more than 3 times without diagnosing the root cause. Repeated failed ignition attempts flood the heat exchanger with unburned gas. ## Estimated Repair Time and Difficulty Most tankless water heater error code C2 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 Rheem 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: Can a venting problem cause C2? Yes — negative pressure from a poorly designed vent system can prevent the gas valve from opening. Ensure the vent meets Rheem’s specifications for length and termination clearances. Q: How do I reset a C2 lockout? Press and hold the temperature Up and Down buttons simultaneously for 3 seconds, or cycle power off and back on at the service switch. ### Is it safe to keep using my Rheem with error C2? If error C2 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 tankless-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 C2 on a Rheem ? Repair costs for error C2 on the Rheem tankless-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 Rheem-authorized service provider for an accurate estimate based on your specific situation. ### What does error code C2 mean on a Rheem tankless-water-heater? Error code C2 on Rheem tankless-water-heater models indicates No ignition — flame not detected after trial for ignition. 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 Rheem with error C2? If error C2 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 tankless-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 C2 on a Rheem ? Repair costs for error C2 on the Rheem tankless-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 Rheem-authorized service provider for an accurate estimate based on your specific situation. ### What does error code C2 mean on a Rheem tankless-water-heater? Error code C2 on Rheem tankless-water-heater models indicates No ignition — flame not detected after trial for ignition. 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.