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Plumbing valves guide: This article describes and illustrate the different types of valves found on water supply and drainage systems as well as plumbing fixture valves and on other plumbing and heating devices & fixtures. We include stop valves, boiler drains, fuel valves, check valves, foot valves, etc. - just about every type of control valve used in residential buildings is defined and illustrated here. This list of the types of control valves found in residential and light commercial buildings includes links to detailed information about each valve type. .
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Thanks to Carson Dunlop Associates, a Toronto Home Inspection Firm and Home Inspection Educator, for permission to use sketches shown in this article. Also see FAUCETS & CONTROLS, KITCHEN & BATH and FAUCETS, OUTDOOR HOSE BIBBS.
As Carson Dunlop Associates' illustrations below show, a broken water control valve stem can obstruct or block water flow through the valve. Globe valves (below left) tend to most restrict water flow compared with the gate valve (center) and ball valve (right). But a broken stem on a gate valve can also leave the valve stuck partly or even fully closed (or open), regardless of how you may be able to turn the valve handle.
[Click to enlarge any image]
Also see SHUTOFF VALVE LOCATION, USE for a discussion of how to find, use, & repair building water supply shutoff valves and stop valves.
Drain Valves: boilers, water heaters, water pressure tanks
Watch out: Often an unused or rarely-used plumbing valve may be stuck, may have lost an internal washer, and may otherwise fail to close properly if you touch it. We advise against attempting to open or adjust heating equipment drain valves unless you are prepared to shut down the system and install a replacement valve in the event of a leaky valve that can't be shut off.
Fuel Valves: oil & gas piping in buildings
Plumbing Fixture Valves
Typically at a sink or toilet the water supply is controlled by a local stop valve.
Plumbing & Heating Controls Valves, Service Valves, Safety Valves
Watch out: do not touch, open, or otherwise manipulate relief valves on heating equipment unless you are prepared, should the valve leak, to shut down the heater and replace the leaky valve immediately.
Other Plumbing System Control Valves
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Frequently Asked Questions (FAQs) about valves found on building plumbing, heating, water supply, and other systems.
Question: Installing a pressurized system & Flushometer Valve Toilets & Urinals on a Well & Pump Water Supply System
I have space above the rest rooms and would like to install a stand alone pressurized system that is fed by the existing residential system, but would provide the gpm and pressure to function the commercial units. Likely to be a total of 3 toilets and two urinals.
Any ideas or plans available? Thanks, Bill
Reply: Be sure that your well water supply system, pressure tank, pressure, and water supply piping diameter & flow rate can support flushometer valves; consider waterless urinal fixtures.
Bill, there is no technical reason why one could not install flushometer type toilets and urinals at a property served by a standard pump and well system, but the cost and trouble may be more than first meets the eye. Where we find flushometer type toilets and urinals installed it's usually at a building served by municipal water supply and employing larger diameter water supply piping than the 1/2" pipe usually found at residential type properties.
Details about flushometer valves and their installation, troubleshooting, diagnosis and repair are now found at FLUSHOMETER VALVES for TOILETS URINALS.
Question: what's the purpose of the inline float valve at the top of an electric water heater? Can I remove it?
What is purpose of & is it necessary ? In- line ball- cock valve in water entry line going into top of electric water heater. Would it be ok to eliminate line containing floating ball ? It sticks & completyely restricts my hot water flow. - Randall Doran
Reply: thermosiphon prevention device?
I'm guessing from your description that you are describing an anti-siphon valve at the top of your water heater. The valve is intended to prevent hot water from circulating up into the building water supply piping by "gravity" (warm or hot water, being less dense than cold water, will naturally rise up out of a hot water tank into cooler water in building piping).
If that's what you've got you could remove the valve but the result might be wasted energy - sending hot water out into building piping (where it will cool off) when no hot water is being drawn at a plumbing fixture.
In general you could eliminate a control valve feeding water into your water heater, but it will make it impossible to turn off "hot" water in the building when service or repair to the heater is needed - you'll instead have to turn off water to the whole building.
Questions & answers or comments about plumbing system valve types & applications.
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