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Standing Pilot Gas Valve Propane Heating | HVAC Heating - How It Works. The standing pilot gas furnace uses a standing pilot to light the main burners. Many gas-fired water heaters have a standing pilot ignition system. The standing pilot gas ignition system is often referred to as a safety pilot because it increases safety.
Safety of ensuring the main burners are lit. The standing pilot can be used on a natural gas ignition system or an LP ignition system. These heating ignition systems are older and are slowly being replaced by more modern and safer electronic ignition systems.
Standing Pilot Gas Valve Propane Heating | HVAC Heating - Thermocouple Problems
The standing pilot ignition system uses a thermocouple to detect the flame on the pilot. As long as the tip remains hot and the standing pilot thermocouple is in good working order the system works well. Heat is provided when the thermostat calls for heat. The thermocouple is the device that proves the pilot flame.
If the thermocouple is not hot it will automatically release the primary valve inside the standing pilot gas valve. If the primary valve in the standing pilot gas valve is closed then the secondary gas valve inside the standing pilot gas valve remains closed. The secondary valve is the valve that feeds gas to the main burners.
Therefore, if the primary valve is closed then the secondary will not get gas to it. This is how the standing pilot gas valve has remained a reliable safe gas ignition system for many years. Sometimes the thermocouple will go bad. If it does then the furnace will not work. You will have to light the pilot light. If the pilot light does not remain lit then it is likely you have a bad thermocouple. There is a procedure to use to test the thermocouple with a multi-meter.
Standing Pilot Gas Valve Propane Heating | HVAC Heating - Types of Fuels
Standing Pilot gas valves can be found in natural gas furnaces as well as propane gas furnace heating systems. Additionally, there are millions of gas-fired water heaters that utilize the standing pilot gas heating systems. Gas-fired water heaters can use either the standing pilot gas valve or electronic ignition gas valves that connected to a solid-state electronic ignition system.
The majority of gas-fired water heaters, however, use the standing pilot gas valve. Standing pilot gas water heaters typically use a thermocouple rather than a thermophile for proving the flame at the pilot light.
Standing Pilot Gas Valve Propane Heating | HVAC Heating - Gas Supply
A standing pilot gas valve has the main gas feed supplied by the large gas pipe. The pilot gas feed feeds gas to the pilot assembly, and a thermocouple or thermophile. The pilot feed is a small pipe originating from the gas valve. The main gas is fed to the valve. However, the main valve inside the standing pilot gas valve remains closed until two things happen.
First, there must be a call for heat from the main thermostat. The thermostat controls heating in the structure being served by the gas furnace. Furthermore, the thermostat is usually set for the comfort level of the occupants to remain comfortable.
Secondly for the furnace to fire the thermocouple or thermophile must prove there is a flame. A flame at the pilot light before the main gas valve will open and fire the main burners. Furthermore, standing pilot gas valves have been operating safely for decades and have proven to be safe.
In some cases, there is a third condition that must be met for the main burner to fire. Some gas furnaces have a switch to prove the fan is running. If there is no air blowing across the heat exchanger the burners will not fire. In older systems, they used sail switches downstream of the heat exchanger. Finally, new systems use a pressure differential switch that closes the contacts when the air is blowing across the heat exchanger.
Repair Parts Available
Standing Pilot Gas Valve Propane Heating | HVAC Heating - Appliance Types
Gas furnaces, gas water heaters, and gas-fired boilers typically use thermocouples. Thermocouples are the method of proving the flame. Gas logs whether they are natural gas, gas logs, or propane gas logs typically utilize a thermophile. However, there some systems out there that have thermocouples.
There are differences between natural gas and propane. To learn more about this see our article Natural Gas Versus Propane.
Standing Pilot Gas Valve Propane Heating | HVAC Heating - Conclusion
Many standing pilot gas valves come with a conversion kit. This is to convert the gas valve from natural gas to propane or from propane to natural gas. It is important to follow all manufacturer’s instructions when converting the system. Conversion from one gas to another. It is also necessary to set the proper gas pressures for the fuel type.
Additionally, gas appliance installation needs to be done by a professional for safety reasons. There are Fuel Gas Codes for piping and appliance installation that need to follow for safety reasons. There are also Mechanical Code considerations that need to be observed.
Standing Pilot Gas Valve Propane Heating | HVAC Heating