Ruud 93

What does Ruud 93 mean?

On Ruud RUTGH condensing tankless water heaters, error code 93 indicates a faulty water flow solenoid. The flow solenoid controls water flow through the unit; when the controller detects it is not functioning correctly, it displays code 93 and stops operation, because correct water flow is required for safe firing and temperature control.

Symptoms

• 93 shown on the remote control LED display
• Heater does not deliver hot water correctly
• Burner cuts out or fails to start
• Inconsistent flow or temperature before the fault

Common causes

• Faulty water flow solenoid
• Solenoid wiring or connection problem
• Stuck or failed solenoid valve

Diagnostic steps

1. 01

   Note the code

   Record that 93 is displayed; the flow solenoid is an internal component, not a user setting.

2. 02

   Power-cycle the heater

   Turn off the faucets, turn off the heater, unplug it for about 30 seconds, plug it back in, restart, then recheck the display.

3. 03

   Confirm the code persists

   If 93 returns after the power cycle, the water flow solenoid likely needs professional service.

4. 04

   Contact a dealer or qualified service technician

   The manual's solution for code 93 is to contact a dealer or qualified service technician to test and replace the water flow solenoid.

When to call a professional

Call a dealer or qualified service technician for code 93. Diagnosing and replacing the water flow solenoid requires opening the unit and working near water, electrical, and gas components. The manual warns to make sure power is off before removing any protective cover and to refer repairs of electrical wiring and other safety devices to a qualified service technician.