Solenoid Valves for Furnaces: A Basic Guide

Solenoid valves are devices that control the flow of fluids or gases by opening or closing an electrically operated coil. They are widely used in various applications, such as heating, ventilation, air conditioning, and refrigeration (HVAC-R) systems. In this article, we will focus on how solenoid valves work in furnaces, what types of solenoid valves are available, and what are their advantages and disadvantages.

How Solenoid Valves Work in Furnaces

A furnace is a device that heats air or water by burning fuel, such as natural gas, oil, or propane. A furnace consists of several components, such as a burner, a heat exchanger, a blower, a filter, and a thermostat. A solenoid valve is a component that regulates the flow of fuel to the burner, which ignites the fuel and produces heat. A solenoid valve opens only when the furnace calls for heat, and closes when the desired temperature is reached. This way, the solenoid valve ensures that the furnace operates safely and efficiently.

There are two main types of solenoid valves used in furnaces: gas solenoid valves and oil solenoid valves. Gas solenoid valves control the flow of natural gas or propane to the burner, while oil solenoid valves control the flow of oil to the burner. The table below summarizes the main differences between gas and oil solenoid valves.


Gas Solenoid Valve Oil Solenoid Valve
Operates at low pressure (less than 1 bar) Operates at high pressure (up to 10 bar)
Requires a pilot light or an electronic ignition to ignite the gas Requires a nozzle and a pump to atomize the oil
Has a fast response time (less than 1 second) Has a slow response time (up to 10 seconds)
Has a simple design and low maintenance cost Has a complex design and high maintenance cost

Advantages and Disadvantages of Solenoid Valves for Furnaces

Solenoid valves have several advantages and disadvantages when used in furnaces. Some of the advantages are:

  • They are reliable and durable, as they have few moving parts and can withstand high temperatures and pressures.
  • They are easy to install and operate, as they only require an electrical connection and a manual valve handle.
  • They are compatible with various types of fuels, such as natural gas, oil, or propane.
  • They are safe and environmentally friendly, as they prevent gas leaks and reduce fuel consumption and emissions.

Some of the disadvantages are:

  • They are prone to failure due to dirt, corrosion, or wear and tear, which can cause the valve to stick or leak.
  • They are sensitive to voltage fluctuations, which can affect the performance and lifespan of the coil.
  • They are noisy and generate heat, which can affect the comfort and efficiency of the furnace.