A vented faucet in a point-of-use hot water system works by allowing pressure to vent through the faucet itself, as there is no valve at the tap gooseneck. This prevents pressure build-up within the small hot water tank.
Understanding Vented Faucet Operation
Here's a more detailed breakdown:
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Open System: Vented faucets are part of an "open" system. Unlike standard faucets connected to a pressurized plumbing system, a vented faucet is directly connected to a small, unpressurized hot water tank.
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No Valve at the Faucet: Critically, a vented faucet lacks a traditional shut-off valve at the spout (gooseneck). The hot water line runs directly from the tank, through the faucet, and to the end of the spout.
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Pressure Relief: As water heats in the tank, it expands, creating pressure. Since the system is "open" and the faucet lacks a valve to hold the pressure, the pressure vents through the faucet spout. This venting is often seen as a slight drip or dribble of water.
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Why Vented Faucets are Necessary: Small point-of-use water heaters are typically low-pressure systems. Using a standard, closed-system faucet would trap pressure within the tank. This could lead to tank damage or even rupture. The vented faucet provides a crucial safety mechanism.
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Components:
- A small, unpressurized hot water tank.
- Tubing connecting the tank to the faucet.
- The vented faucet itself (with no shut-off valve at the spout).
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Operation: When you turn on the faucet, gravity feeds water from the tank through the tubing and out of the spout. The lack of a valve means the system remains open to the atmosphere, preventing pressure build-up.
In essence, a vented faucet is a safety valve designed to prevent pressure accumulation in a small, point-of-use hot water tank by allowing water to vent through the spout.
