Screened Warning Pipe A screened water pipe is a requirement under the water regulations. The pipe should be one size larger that the supply pipe feeding the cold water storage tank. The dip pipe is fitted on the inside of the tank. The warning pipe warns if the water level in the tank is to high.
Cold Water Storage Tank Cold water tanks are typically made from plastic. To comply with current water regulations they should have a tight fitting lid. Older tanks you may encounter could be made od asbestos reinforced concrete or galvanized steel. The shape of the cold water tank can vary depending on the where it is intended to fit. The out let pipe is connected to the CWST via a tank connector.tank connector.
Float Operated Float operated valves control the amount / level of water in the cold water storage tank or cistern. The float rises and closes the valve stopping the flow of water. Pictured below is the symbol for a float valve. There are two main types of float operated valve the Portsmouth and the diaphragm valve.
The Portsmouth These are an older pattern of valve; they most not be used in toilet cisterns, and should not be used in cold water storage tanks. This is because the outlet is at the bottom of the valve and there is a possibility that contaminated water may make it back up into the water supply pipe.
Diaphragm Valve These valves should be used in cold water storage tanks and cold water cisterns. The out let is over the top of the valve body greatly reducing the chance of contamination.
The stop tap and service valve isolates mains pressure water from the system or component allowing the plumber to work of the system without flooding the property. All float operated valves must have a method of isolating them. Stop Tap / Service Valve
Stop Tap The stop valve is capable of isolating water pressures between 0.5 – 10 bar. The water flows into the valve and is stopped by the washer at the end of the valve stem. The stop tap is usually a compression fitting but push fit versions are available.
Service Valve The service valve as the name suggests allows the plumber to isolate an individual component or system part, enabling them to work on the part without turning off the water supply the rest of the property. The service valve can be screwdriver operated or level operated. Both types use a highly polished ball with a hole through it seated in a nylon seat as the ball is rotated it aligns the hole with the bore of the pipe allowing water to flow.
Gate Valve Gate valves are used to control the flow of water from the outlet of cold water storage tanks. Gate valves are used because they offer the least restriction to the flow of water. Gate valves should not be used on mains pressure pipes as most are not rated for mains pressure.
Gate Valve As the valve stem is turned it raises and lowers the gate. The water seal is achieved between the matting faces of the brass / bronze gate and the body of the valve; no gaskets or seals are used.
Bath Tap Bath taps come is single pillar taps, mixer taps or mixer taps with shower attachment. The majority of bath taps have a threaded connector to accept a 22mm tap connector.tap connector
Basin Tap Basin tapes come in single pillar tap and mixer. The mixing tap pictured left is a mono block tap; meaning the tap body is of a one piece design. Basin taps are threaded to accept a 15mm tap connector.tap connector
Tap Connector Tap connectors are used to connect the tap to the pipe work. They can be soldered, push-fit or compression. Tap connectors can be incorporated into flexi-hoses removing the need to produce an offset. Hospitals do not allow the use of flexi-hoses as they are a potential hot spot for bacteria growth.
Tank Connector The tank connector has a threaded flange with two projections moulded into the back; these are to hold the tank connector in place when you tighten up the flanged locking nut. The other end of the tank connector has a compression fitting. When fitting a tank connector the hole is cut using a hole saw.
Drain Off Valve The drain-off valve can be a solder fitting, threaded fitting or incorporated into an other component such as a compression coupler or gate valve. The drain-off should be located at the lowest part of the system to enable the water to be drained from the entire system. A drain-off should be fitted after the stop tap to allow you to drain off the water from the property.
Water Closet Cistern A water closet (WC) cistern can be close coupled or wash down connection to the pan. Older cisterns have a warning pipe similar the cold water storage tank. Modern cisterns the warning pipe discharges into the pan.