What does Rheem Water Heater No Ignition - Causes & Fix mean?

Low gas supply or a latched control fault. For LPG, check propane bottle level, cycle power at the outlet, and reopen the tap.

How do I fix Rheem Water Heater No Ignition - Causes & Fix?

Follow the step-by-step diagnosis below. The most likely fix is identified by checking power, sensor resistance, and control-board signals in order — using a multimeter and the part numbers documented in the parts reference table.

Can I keep running the equipment with this fault active?

Generally no. Faults on Water heater units are emitted when a sensor, safety, or control circuit is outside its operating envelope. Running through an active fault risks compressor, heater, or control-board damage. Diagnose and clear the fault first.

What part is most commonly replaced for Rheem Water Heater No Ignition - Causes & Fix?

The most frequently replaced parts for Rheem Water Heater No Ignition - Causes & Fix are listed in the Parts Reference section of this guide with OEM part numbers and typical price ranges. Check the table for direct replacements.

Is Rheem Water Heater No Ignition - Causes & Fix a DIY repair or do I need a technician?

Sensor swaps, fan motor replacements, and condenser cleaning are typical DIY-level repairs. Anything involving refrigerant, gas, or high-voltage (>240V) work requires a licensed technician for both safety and code-compliance reasons.

Rheem Water Heater No Ignition - Causes & Fix

Rheem Water Heater No Ignition — What’s Happening

On Rheem continuous-flow gas water heaters, no ignition at start-up is logged as Code 11, which Rheem defines as “Ignition failure at start up.” The unit is calling for heat and the ignition sequence begins, but the burner does not establish flame within the allowed start-up window. This is different from Code 12, which is flame loss during operation. Code 11 is a start-up fault, not a pilot-light issue, and it means the igniter or gas delivery chain has failed to complete the lighting cycle when hot water is first demanded.

Jump to Fix

Most Likely Causes

Low LPG bottle level or inadequate gas supply Rheem explicitly calls out low propane bottle level or insufficient gas pressure as the primary culprit for Code 11 ignition failure at start-up.
Controller latched in fault after a previous ignition attempt Rheem’s own troubleshooting includes a power-cycle reset step, which suggests the control board can stay locked in fault mode until cycled off and back on.
Blocked vent or combustion-air pathway Field technicians commonly inspect the concentric vent or flue outlet for obstruction that prevents safe ignition or air flow to the burner.
Failed or dirty igniter coil Repair videos show attention to the igniter coil and its wiring, as a weak or intermittent spark will prevent flame establishment during start-up.
Gas solenoid not opening or out of spec Technicians check that all gas solenoids are powered and within service-manual resistance values, since a valve that fails to open will block gas to the burner.
Dirty burner or manifold blocking gas flow Soot, debris, or insect nests in the burner and manifold can prevent gas from reaching the ignition point even when the igniter sparks.
Loose or corroded ignition-circuit wiring Field repairs sometimes involve reconnecting the circuit-board wire to the igniter coil when the connection has come loose or corroded over time.

How to Diagnose and Fix

Confirm the display shows Code 11 and that the fault occurs at start-up, not after the flame has already been running.
Check gas supply first. For LPG, verify the propane bottle has adequate fuel and the regulator is functioning. For natural gas, confirm the supply valve is fully open.
Close the hot tap, switch the heater off and back on at the GPO (outlet), wait ten seconds, then reopen the hot tap and listen for ignition.
Inspect the concentric vent or flue outlet from the outside for blockage, bird nests, or debris that could restrict air flow or exhaust.
Observe the ignition sequence through the viewing window (if equipped) or listen for the spark clicking. If there is no spark, the igniter coil or its wiring may be disconnected or failed.
If you hear spark but no flame, check that gas solenoids are clicking (being energized) and that the burner area is free of soot or blockage. Cleaning the burner and manifold with compressed air is a common field fix.
Verify all wiring connections between the control board and the igniter, gas valve, and flame sensor are tight and free of corrosion.
If Code 11 persists after gas supply, reset, and basic inspection, book Rheem service or call a licensed gas technician to test solenoid resistance, gas pressure, and replace faulty ignition components.

Parts You Might Need

Part	Notes
Igniter coil (Rheem tankless)	Amazon \| Generates the spark to light the burner at start-up. Confirm your model before ordering.
Gas solenoid valve (Rheem continuous-flow)	Amazon \| Controls gas flow to the burner. Technicians verify resistance against service-manual spec before replacing.

If your appliance also shows a code on the display, these match this problem:

When to Call a Pro

Rheem’s official guidance for recurring Code 11 is to book service. Gas solenoid testing, manifold pressure measurement, and igniter-coil replacement all involve working inside a gas appliance and should be handled by a licensed gas technician. If your reset attempt and basic vent check do not restore ignition, or if you smell gas at any point, shut off the gas supply and call a pro immediately. For gas line, burner, or igniter work, or if you ever smell gas, stop and call a licensed technician.