What is a Gas Thermostat?

A gas thermostat is a device that regulates the temperature of a system using gas for energy. Water heaters, furnaces, and ovens rely on a thermostat for stable temperature control. Thermostats can also regulate the temperature in a gas-fired fridge, where the goal is cooling, rather than heating. Thermostats can work in a number of ways, and a malfunctioning thermostat may cause a system to stop firing or regulate temperature incorrectly.

Some gas thermostats operate mechanically. An example is a tube filled with gas. As the temperature changes, the gas expands and contracts to adjust a control screw, regulating the amount of propane released for burning. Bimetallic thermostats are another option, relying on changes in two metals to detect the temperature and determine whether more or less gas is necessary to achieve the desired temperature. Others use electrical systems rather than mechanical moving parts.

Users can set the gas thermostat to determine the temperature. The device may allow people to select a specific temperature. In other cases, it has settings like cool, warm, and hot, and the thermostat will keep the temperature within a controlled range at each setting. This can be helpful for energy efficiency, as the thermostat will not kick in every time temperatures change by just a few degrees, but only when temperatures pass outside the set range.

The gas thermostat needs to be upright and in the proper position to work correctly. Thermostat failures can be the result of dirt in the workings, loose wires, pieces out of position, or damage caused by people leaning on or hitting the thermostat. Usually it is easy to quickly assess the condition of a gas thermostat by lifting the cover of the user control panel and checking for any obvious signs of damage. People can also follow the thermostat wire to the sensors to see if the problem lies there.

To determine if a gas thermostat is working, people can change the temperature setting radically to see if the gas starts firing. If it does not, there may be a problem with the thermostat or the gas regulator. Thermostat replacement requires a gas technician who can make sure the device is properly connected to the system. With an electronic thermostat, the technician can also run some diagnostics to find out more about why the device is not working, and determine if it is possible to make a repair rather than replacing the whole unit.