controls- standing pilot

Introduction

This section covers the key components and functions of gas water heater controls, with a focus on standing pilot gas valves. Frank provides a detailed explanation of how to operate these controls and their safety mechanisms.

Standing Pilot Gas Valve Overview

The standing pilot gas valve is an essential component found in many gas water heaters. It is referred to as a classic gas valve.

Gas Control Knob

  • Location: Situated at the top of the gas valve.
  • Settings: The knob features three settings:
    • On: Activates the main burner.
    • Off: Deactivates gas flow.
    • Pilot: Allows gas to flow to the pilot light.
Function of the Pilot Position

When the gas control knob is set to pilot, pressing the red pilot button permits a small amount of gas to flow through the pilot tube, enabling the user to ignite the pilot light.

  1. Ignition Source: A long match or an extended butane lighter is recommended for lighting the pilot.
  2. Procedure:
    • Press down the pilot button.
    • Ignite the pilot light using the chosen ignition source while holding down the button.
    • Maintain pressure on the button for 30 seconds to 1 minute to warm the thermocouple. If the pilot stays lit after releasing the button, it indicates successful ignition.

Temperature Dial

  • Typical Settings: The temperature dial typically features options like:
    • Hot
    • Warm
    • Vacation (factory default at approximately 70 degrees).
  • Warnings: A warning is displayed indicating the risk of scalding if the hot setting is exceeded.
  • Vacation Mode: In this mode, the pilot stays lit, and the burner will only activate if the ambient temperature surrounding the water heater drops below 70°F.

Burner Assembly

The burner assembly is crucial for the operation of the water heater as it manages the flow and distribution of gas.

Burner Tube

  • The burner tube connects directly to the gas valve's center. It plays a vital role in transporting gas to the burner plate.
  • Orifice: Located at the bottom of the burner tube, it directs gas into the burner plate, facilitating gas distribution in a circular pattern at the tank's base.

Thermocouple

  • Function: The thermocouple is a safety device that generates a millivolt signal when the pilot flame is lit. This signal prevents the gas valve from opening if the pilot is not ignited, thus avoiding the hazard of unburnt gas accumulating nearby.
  • Operation: It screws into the gas valve’s left side, providing feedback based on the pilot flame status.

Pilot Tube

  • Composed of flexible aluminum, the pilot tube feeds the pilot light while ensuring a seal via a brass compression fitting. It ensures just enough gas passes through to sustain the pilot light.

Burner Plate

  • This remains a consistent design feature across water heaters, proving to be effective and reliable over time.

Pilot Burner

  • The pilot burner is characterized by a capped tube with side openings that direct the flame toward the thermocouple, enhancing its exposure to the heat.

Comparison of Gas Valve Designs

Frank highlights an alternate gas valve design, which shares common features with the previous example but incorporates a direct immersion temperature probe.

Temperature Probe

  • Location: This probe is threaded into the side of the tank and directly immersed in the water, allowing accurate temperature sensing.

Gas Inlet

  • Typically uses a half inch iron pipe thread. Caution is advised when applying pipe dope to prevent contamination of the valve’s internal mechanisms.

Temperature Dial

  • Similar in function to the previous design, providing practical settings for water temperature regulation. Turning it all the way down will leave only the pilot setting active.

Conclusion

Frank concludes the segment by summarizing the main features and functionalities of gas water heater controls, particularly standing pilot gas valves. This knowledge is critical for safe and effective operation of gas water heaters, helping to ensure both efficiency and safety for users.