Knowing how to turn off the various parts of a household plumbing system is essential if there’s a plumbing emergency, there’s a minor leak, you need to change a fitting or appliance, or you are making some modification to the plumbing.
Mains Water Supply – Direct Feed
You can switch off the mains water supply into the house at the main stop cock or stop valve which is usually located under or near the kitchen sink.
If there isn’t a stop valve or you cannot find it then you’ll have to turn the water off at the Water Authority’s stop valve out in the street. These can sometimes be difficult to find but are normally in the pavement just outside the boundary of your property. Depending on the valve, you may need a special key to switch this off.
Indirect Feed Water Supply
Many parts of the plumbing system are fed indirectly. Water stored in a cold water storage cistern in the loft supplies all the indirect appliances and outlets such as bathroom taps and toilet cisterns. To turn off the water coming from the cold water storage cistern you will need to shut off the valve on the cistern’s outlet supply.
Isolating Water to Individual Appliances
Isolating valves are used for many appliances now. It is common to see an isolation valve on the pipe feeding a wc cistern, washing machine or dishwasher as well as on heating runs and pipes feeding bathroom taps. This is a huge advantage as it means that these can be turned off to isolate them without having to close off all other outlets on the same pipe work. Isolating valves may be either screw head operated or of the lever type and require only a half turn to close or open.
Hot Water Supply
If you have a combi boiler then the hot water is supplied direct. In this case closing the mains stop valve will close off the water. If you have a hot water cylinder – usually in the airing cupboard – this will be an indirect supply. There will be a valve on the pipe from the cold water storage cistern to the hot water cylinder. Closing off this valve will stop the feed to the cylinder and therefore the hot water at the taps.
Central Heating Systems
If you need to drain down your central heating system to carry out repairs or maintenance, you need to know how to temporarily stop it refilling. On a sealed system there is no new water being supplied unless the filling loop is opened. In its working state, this filling loop remains closed except if the system needs topping up. So if you have to empty this type of heating system it will only refill when the filling loop is opened. On a vented system, the water level is kept topped up by the feed and expansion cistern. Therefore if you drain down this type you will need to temporarily close off the supply from here till you’re ready to refill. Either close off the valve on the incoming pipe to the cistern or, fix a batten across the top and tie up the float valve