Direct Hot Water What Cold Water System is Pictured? What hot Water System is Pictured? The cold water storage tank acts as a reservoir; it supplies cold water to the hot water cylinder in the direct hot water system. Newer cold water tanks tend to be sealed to comply with the water regulations. Older open toped tanks may be encountered and these should be rectified to comply with current regulations. Cold Water Storage Tank Byelaw Kit The byelaw kit contains all of the components to make the CWST comply with the regulations. The kit contains;- Tight fitting lid Part 2 float valve Insulation jacket Screened vent Screened warning pipe Tank Connector A tank connector is used to connect water pipes to the cold water storage tank. The flanges on the connector provide a large clamping surface; there should be a compressible washer / gasket on the inside of the tank to provide a water proof seal. The other end of the tank connector has a compression fitting or sometimes a pushfit connection. Hot Water Cylinder The direct hot water cylinder can be identified by the number of ports on the cylinder. There should be two ports for the inlet and outlet; and a heating element port A B Question What type of hot water cylinder is A? What type of hot water cylinder is B? Hot Water Cylinder Cold water in at the bottom of a cylinder hot water out from the top of a cylinder The cylinder needs to be insulated to make the cylinder energy efficient and reduce wastage Pipes should be lagged up to 1 meter from the cylinder or until they disappear into the floor or wall. Emersion Heater An emersion heater is fitted to a hot water cylinder by a threaded connection. The heater has a seal to make the connection waterproof but it is recommended that a jointing compound also be used. The element is fitted using an emersion heater spanner. Emersion Heater The section of the emersion that is inserted into the hot water cylinder consists of two parts. The element Is made from a resistive wire that is insulated and sealed in a copper tube, when and electrical current is passed through the wire it heats up warming the surrounding water. The thermostat Is wired in series to the element, when the water reaches the required temperature the thermostat turns the power off. As the water cools the thermostat registers the temperature drop and turns the power back on. The emersion heater element has a protective metal cover; to remove this undo the retaining nut. Inside the cover you will see the; Neutral terminal. Thermostat Thermal cut out switch. Live terminal of heating element. Emersion Heater Connections The live wire is connected to the terminal in the thermostat. The power is then connected by the white wire to the thermal cut out switch. From the thermal cut out switch the power goes to the live terminal of the heating element. The circuit is completed by the neutral cable connected to the neutral terminal. Emersion Heater Connections The thermostat controls the temperature of the water; It does this by turning off the power to the element when the water is at the required temperature and turning the power back on when the water temperature drops below what it has been set to. The temperature of the water is adjusted by turning the control knob. NB this thermostat has a built in thermal cut out switch; this switches the power off if the temperature gets too high and has to be manually reset before the heating element will start working again. Thermostat Switch Spur Emersion heaters use a large amount of power; as a result they should have there own switched spur. The switched spur should be a two pole switch normally fitted with an indicator light to shop the circuit is energized. The cable leading from the switch to the immersion heater should be flexible and heat resistant. The cable connecting the emersion heater to the switch must be heat resistant. It should be rated at least 85C. Heat resistant cable should be used where ambient temperatures exceed the working range of standard PVC cables which is +5C to 70C. Heat resistant cables are usually made from butyl. There should be no longer than 1m of flex from the two pole switch to the immersion heater. Switch Spur Cable Two-Pole Switch The switch for an emersion heater is two pole; this means that both the live and the neutral is switched. Two pole switches are safer as they isolate both of the conductors. Some switches have an indicator light to show there is power to the circuit. Stratification Stratification is the phenomenon of water of different temperatures forming into strata or layers. The lower layers are the coldest whilst the highest layers are the hottest. Stratification