The gas valve is the most critical control component in your gas fireplace. It regulates gas flow to both the pilot burner and the main burner, and it contains the safety mechanisms that shut off gas if the pilot goes out. When a gas valve fails, the fireplace either will not operate at all or may operate unsafely.

Understanding the different types of gas valves used in fireplaces helps you identify what is in your unit, communicate effectively with technicians, and order the correct replacement when needed. This guide covers the four major gas valve manufacturers found in residential gas fireplaces: SIT, Honeywell, Robertshaw, and Maxitrol.

How Gas Valves Work in Fireplaces

Before diving into specific brands, it helps to understand the basic function of a fireplace gas valve. Regardless of manufacturer, all fireplace gas valves perform three essential functions:

1. Manual gas control: The knob on the valve allows you to select OFF, PILOT, or ON positions. In the PILOT position, gas flows only to the pilot burner. In the ON position, gas can flow to both the pilot and the main burner.
2. Safety shut-off: The valve contains an electromagnetic safety device (powered by the thermocouple) that automatically shuts off all gas if the pilot flame goes out.
3. Main burner control: The valve opens and closes the main burner gas supply in response to signals from a wall switch, thermostat, or remote control system. In millivolt systems, this is powered by the thermopile. In electronic ignition systems, this may be powered by an external power supply.

SIT Gas Valves

SIT (formerly SIT Group, based in Italy) is the most common gas valve manufacturer in the fireplace industry today. You will find SIT valves in fireplaces from Heat N Glo, Heatilator, Napoleon, Lennox, Majestic, Monessen, Empire, and many other brands.

Common SIT Valve Models

• SIT 630 Eurosit: The most widely used gas valve in the industry. This is a multifunctional valve with a built-in thermostat, making it ideal for vent-free and some vented fireplace applications. The 630 has a distinctive rectangular body and a control knob that clicks between positions.
• SIT 820 Nova: A more modern design commonly found in direct vent fireplaces. The 820 Nova features a sleeker profile and is often used with external remote control systems. It comes in millivolt and electronic ignition variants.
• SIT 885 Proflame: Found in fireplaces designed for full electronic control. The Proflame system integrates the gas valve with a proprietary remote control receiver, allowing variable flame height control from the remote. This valve is common in higher-end Napoleon and other premium fireplace brands.

Identifying a SIT Valve

SIT valves are identifiable by the SIT logo stamped on the valve body and a model number tag on the side. The model number format is typically three digits (like 630, 820, or 885) followed by additional digits indicating the specific configuration, gas type, and orifice size.

Browse our selection of SIT gas valves and controls.

Honeywell Gas Valves

Honeywell (now Resideo for home products) has been manufacturing gas controls for decades. Honeywell valves are found in many mid-range and builder-grade fireplaces, as well as in older units from various manufacturers.

Common Honeywell Valve Models

• Honeywell VS820: A popular millivolt gas valve used in many vented and vent-free fireplaces. The VS820 is a combination valve with a built-in pilot safety (thermocouple connection) and thermopile-powered main valve.
• Honeywell VR8200: An electronic ignition gas valve used in fireplaces with IPI (Intermittent Pilot Ignition) systems. This valve requires 24V power and is controlled by a separate ignition module.
• Honeywell VR8300: Similar to the VR8200 but configured for standing pilot applications. Common in older installations.
• Honeywell SV9500/SV9600 series: SmartValve systems that combine the gas valve and ignition control into a single unit. Found in some higher-end fireplace installations.

Identifying a Honeywell Valve

Honeywell gas valves have the Honeywell or Resideo name printed on the valve body. The model number is on a label on the side of the valve and begins with letters (VS, VR, SV) followed by numbers. The label also shows the gas type, inlet/outlet pressure ratings, and orifice size.

Robertshaw Gas Valves

Robertshaw gas valves were once extremely common in gas fireplaces, particularly in units manufactured in the 1990s and 2000s. Robertshaw was acquired by Uni-Line (now part of Emerson), and many Robertshaw valves have been discontinued. However, millions of fireplaces with Robertshaw valves are still in service.

Common Robertshaw Valve Models

• Robertshaw 710-502: A widely used millivolt combination gas valve. This valve has a distinctive elongated body and was standard equipment in many fireplace brands for years.
• Robertshaw 7000 series: Various configurations for different gas types and applications. These are direct-replacement valves for many fireplace installations.
• Robertshaw 7200 series: Electronic ignition valves that work with external control modules.

Finding Robertshaw Replacements

Since many Robertshaw valves are discontinued, finding exact replacements can be challenging. In many cases, a compatible SIT or Honeywell valve can be substituted, but the replacement must match the original in gas type, connection size and orientation, pilot outlet position, and electrical connections. Consult a qualified technician before substituting a different brand valve.

Maxitrol Gas Valves and Regulators

Maxitrol specializes in gas pressure regulators and controls. While not as commonly found as the primary gas valve in fireplaces, Maxitrol components are frequently used in conjunction with other gas valves as pressure regulators and modulating controls.

Common Maxitrol Products in Fireplaces

• Maxitrol GV36 series: Gas valve regulators used in some fireplace applications, particularly in units with modulating flame control.
• Maxitrol RV series: Pressure regulators used to step down gas pressure before it reaches the main gas valve. These are commonly found in areas with high-pressure gas supply.
• Maxitrol M511 series: Motor-operated modulating valves that allow precise flame height control. Found in higher-end fireplace systems with variable flame height features.

Maxitrol in Remote Control Systems

Maxitrol also manufactures the Mertik Maxitrol remote control system, which is used in fireplaces from several manufacturers. The Mertik system integrates a motorized gas valve with a dedicated remote control transmitter and receiver. Learn more about how this system compares to other options in our guide on SIT Proflame vs Skytech vs Mertik Maxitrol remote systems.

Browse our selection of Maxitrol gas controls and regulators and Mertik gas valves.

How to Identify Your Gas Valve

If you need to identify the gas valve in your fireplace:

1. Locate the valve: Open the lower access panel of your fireplace. The gas valve is the metal component where the gas supply line connects and where the control knob is mounted.
2. Find the manufacturer name and model number: Look for a label or stamped text on the valve body. The manufacturer name is usually prominent.
3. Note the gas type: Natural gas (NG) and propane (LP) valves are different and not interchangeable without a conversion kit.
4. Photograph the valve: Take photos of the label, the valve from multiple angles, and the connections. This is invaluable when ordering a replacement.
5. Record your fireplace model number: The fireplace manufacturer specifies exactly which gas valve should be used. See our guide on finding your gas fireplace model number.

Millivolt vs Electronic Ignition Valves

Gas valves come in two fundamental types based on the ignition system they work with:

• Millivolt valves: Powered entirely by the thermopile (no external electricity needed). These valves are simpler, work during power outages, and are found in standing pilot systems. They have connections for a thermocouple and thermopile.
• Electronic ignition valves: Require external power (typically 24VAC) and are controlled by an electronic ignition module. These valves are more complex but allow more features like automatic relighting and integration with smart home systems.

For a detailed comparison, see our guide on millivolt vs electronic ignition gas fireplaces.

When to Call a Professional

Gas valve work is one area where we strongly recommend professional service:

• Gas valve replacement should always be performed by a licensed gas technician. Improper installation can cause gas leaks, carbon monoxide hazards, or fire. Our informational guide on how to replace a gas fireplace gas valve provides context on what the job involves.
• Gas pressure testing: After any gas valve work, a technician must perform a leak test and verify gas pressure with a manometer.
• Cross-brand substitutions: If an exact replacement valve is unavailable (common with discontinued Robertshaw models), a technician can determine which compatible valve will work safely.
• Conversion between gas types: Switching from natural gas to propane (or vice versa) requires changing orifices, adjusting regulators, and often replacing the gas valve. This is not a DIY project.

For all your gas valve and fireplace control needs, shop our complete selection of gas valves and conversion kits.