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Adjusting Different Types of Toilet Ballcocks


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Introduction to the Ballcock or Fill Valve
ballcock - fill valve

Ballcocks (or fill valves) come in a variety of types such as plunger, diaphragm, float-cup and floatless designs.

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Overview of the Toilet Ballcock
The toilet in your home has several tank components but there are only two main valves at work every time you flush the toilet; the fill valve (also called a ballcock) which fills the tank with water, and the flush valvewhich releases the water stored in the tank into the toilet bowl for flushing.

You may not need to replace the toilet if you only need to upgrade the ballcock or fill valve to modern standards.

    Types of Ballcock:
    The ballcock or fill valve comes in four basic variations. In this tutorial we will review the features of each ballcock type and how to adjust them for proper operation:
  • Plunger / Piston Type Ballcock (uses rod and float ball)
  • Diaphragm Type Ballcock (uses rod and float ball)
  • Float Cup Type Ballcock
  • Floatless Type Ballcock

Anti-Siphon Capabilities:
Worth noting is that anti-siphoning capabilities are required on fill valves by plumbing code. Think of an anti-siphoning device as a one-way valve. Anti-siphon devices protect against a period of low water pressure in the supply line where contaminated water could be sucked back into the potable water supply. Modern US plumbing codes require the ballcock to have an anti-siphon device as an integral part of the fill valve itself. The anti-siphon device can be a vacuum breaker or an air gap and is located on the side of the ballcock where water leaves the fill valve and flows through the refill hose and into the overflow pipe.

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