Q:

# How does a pilot valve work?

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A pilot valve in a hydraulic system acts as a pressure-control valve allowing hydraulic fluid to pass through to another valve using either a sliding or a poppet design. If there is too much pressure on hydraulic liquid, the pilot valve will open up and let liquid pass through to diminish the pressure.

## Keep Learning

Hydraulic systems make use of incompressible liquid in different-sized pistons. The systems allow for force that is exerted on a small piston to be magnified in the large piston. When force is applied to the small piston, Pascal's law states that pressure must be equal throughout the entire liquid, so pressure is built up in the larger piston which creates a magnified force because of the larger area of the chamber.

The hydraulic liquid passes through a series of valves in between the two pistons. The pilot-valve typically has a spring or electronic press on a stopper that will only open up at a certain pressure. If the pressure of the liquid exceeds the allowed pressure on the stopper, the valve will open up and allow liquid to run through it in one direction to equalize the pressure. The entire hydraulic system depends on the pilot valve, if the pilot valve opens too early or too late, then the entire system does not work properly.

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## Related Questions

• A:

To troubleshoot a Napoleon gas fireplace that will not stay lit, check the drip loop, the pilot light, the thermocouple and the gas valve to ensure all components are clean and working before replacing. If the gas fireplace pilot light will not stay lit, troubleshooting common problems can usually fix this issue.

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• A:

Pilot light systems can be lit with a match or lighter, but it's best to turn the pilot valve to the "off" position to let the gas disperse first. The valve should be moved to "pilot" from the "off" position and then to the "on" position once lit.

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• A:

Lighting a gas furnace involves turning off the pilot valve, lighting the pilot with a long fireplace match, then turning the gas knob to the On position. This process takes less than half an hour.