Richmond Error Code 79 — Causes & Fix

Richmond error code 79 indicates a leak detection alert — the unit's water sensor (in models equipped with leak detection) has detected water in the drain pan or condensate area, suggesting a tank or fitting leak. The unit may automatically shut off heating as a protective measure.

What triggers code 79

Newer Richmond residential water heaters include a moisture sensor at the base of the unit or in a separate drain pan. The sensor detects water presence and reports the condition to the control board, which displays code 79 and (depending on configuration) shuts off heating to prevent worsening damage if the cause is a tank leak.

Critical first action

Code 79 indicates water is somewhere it shouldn't be. Before diagnostics:

1. Shut off cold water supply to the unit (close the inlet valve)
2. Open a hot fixture to relieve pressure
3. Visual inspection to identify water source
4. If active leak from tank wall: tank failure — full replacement required
5. If condensate or T&P discharge: less urgent but still requires diagnosis

Diagnostic steps to identify leak source

1. Tank wall leak: water seeping from the tank itself (welds, glass-lining failure points). Visible water trail down the side or from the base. Tank failure — replacement required.
2. T&P relief valve discharge: water from the T&P discharge tube. Normal occasional discharge during temperature/pressure fluctuations; continuous discharge indicates T&P failure or thermal expansion issue (verify expansion tank).
3. Drain valve leak: dripping from the drain valve. Tighten or replace the drain valve ($15–25 part).
4. Inlet/outlet fitting leak: at the cold inlet or hot outlet pipe connections. Tighten fittings; replace dielectric union if damaged.
5. Condensate (gas condensing models): condensate drain blockage causes backup. Clear the drain line and neutralizer.
6. Anode rod port leak: if anode was recently replaced, gasket may not be sealing. Re-tape and retighten.

Sensor false alarm scenarios

• Recent maintenance or install: water spilled during service can trigger the sensor. Dry the sensor area and reset.
• High humidity: condensation in humid spaces can wet the sensor. Verify dry conditions.
• Sensor failure: rare but possible. Sensor reports water when none present. Test by drying sensor and verifying it doesn't false-trigger.

Reset procedure

After confirming and addressing the water source:

1. Dry the area around the sensor completely
2. Restore cold water supply
3. Verify no leaks at all connections
4. Reset by cycling power or pressing the leak-sensor reset button (location varies by model)
5. Monitor for 24 hours to verify no recurrence

If code 79 recurs without visible water

Possibilities:

• Slow leak from a hidden location (back of tank, beneath insulation)
• Condensate accumulating slowly in a hidden area
• Sensor sensitivity issue or false alarm

Professional service to identify hidden leak source or sensor calibration may be needed.

Tank leak: replace, don't repair

If diagnostic confirms tank wall leak, do not attempt to repair the tank. Glass-lined tanks cannot be field-repaired once the steel wall is compromised. Replacement is the only solution. If under warranty, claim the warranty replacement. If out of warranty, plan replacement immediately — leaks worsen rapidly and a small seep becomes a flood without warning.

Insurance considerations

If code 79 led to water damage in surrounding finished spaces (drywall, flooring, ceiling below), document everything with photos before any cleanup. Homeowners insurance typically covers water damage from sudden water heater failure but requires documentation of the failure mode and timing.