Unvented Cylinder Manual 09_12

The factory fitted

The factory fitted temperature & pressure relief valve at the top of the cylinder is a safety device to back-up the thermostat(s) and thermal cutout(s). It works by sensing an excess in water temperature or pressure and releasing the hot water into a discharge tundish and drain. The cylinder will only work in the vertical position. The inlet pipe needs to deliver cold water to the bottom of the tank. When water is heated it expands. To accommodate this increase in volume an expansion vessel is provided. A cold water combination valve is also provided in two pieces, loose jointed for ease of installation. These comprise a combined line strainer/pressure reducing valve and core non-return valve/expansion relief valve. 2.3 Delivery The Ariston range of Unvented Cylinders are available in the following options: The Wall-hung ProTech cylinder (100 litre model), which is supplied as follows; One box containing; 1) The cylinder with factory fitted temperature & pressure relief valve, immersion heater and thermostat with thermal cut-out. One box containing; 1) Unvented control pack (expansion vessel, 2 piece cold water combination valve and tundish), instructions for installation, servicing and use including the Benchmark Log Book). The STD and STI floor standing range (125, 150, 200, 300 and 500 litre models) and the ITD and ITI floor standing range (80*, 130, 150, 215, 255* and 305 litre models) are supplied as follows; One box containing; 1) The cylinder with factory fitted temperature & pressure relief valve, immersion heater(s) and thermostat(s) with thermal cut-out(s), cylinder thermostat with thermal cut-out (indirect only). 2) Unvented control pack (expansion vessel, 2 piece cold water combination valve and tundish), motorised valve (indirect only, non-high temperature), expansion vessel mounting bracket, instructions for installation, servicing and use including the Benchmark Log Book. The ITSI twin coil floor standing range (215, 255 and 305 litre models) are supplied with the following; One box containing; 1) The Cylinder with factory fitted temperature & pressure relief valve, immersion heater and thermostat with thermal cut-out, cylinder thermostats with thermal cut-outs. 2) Unvented control pack (expansion vessel, 2 piece cold water combination valve and tundish), 1 x motorised valves (non-high temperature), expansion vessel mounting bracket, instructions for installation, servicing and use including the Benchmark Log Book. * ITI only 4

3. INSTALLATION 3.1 wAter reGulAtions 3.2 BuilDinG reGulAtions 3.3 GenerAl GuiDAnce The appliance should be installed in accordance with the Domestic Heating Compliance Guide. These regulations (byelaws in Scotland) ensure a good supply of wholesome water, and that only approved materials, pipes and fittings are used to convey water. These are a statutory document and take priority over all other regulations and recommendations. The installation of an unvented hot water storage cylinder is classified as a “Controlled Service” and Regulation G3 applies (England & Wales. For Scotland, NI and ROI, local Building Regulations apply). To meet the requirements of the Regulation, installation of an unvented system should be undertaken by a “competent installer”. All installations of unvented hot water storage systems having a capacity of more than 15 litres should be notified to the relevant Local Authority by means of building notice or by the submission of full plans. It is important to note that it is a criminal offense to install an unvented hot water storage system without notifying the Local Authority. The installation of the unvented cylinder and hot water system must comply with BS 6700 and the HSE Legionella Code of Practice. Current guidance notes do not cover the connection of a solar thermal circuit to an unvented storage vessel (cylinder). However, if guidance is sought for compliance with current regulations the fundamental principle is to provide a failsafe means of shutting off the solar input to the heat exchanger if the cylinder temperature should rise above the set temperature of the cylinder’s energy cut out. (See Note 1). As with all unvented hot water systems, notification of intention to install should be given to your local building control. Option A. A non self resetting mechanical shut-off should be installed on the solar primary flow to the cylinder. The mechanical shut-off should be suitable for use with a solar primary circuit (i.e. high temperature and glycol resistant). The mechanical shut-off should be integrated electrically with the cylinder energy cut out/s and if necessary the solar circuit temperature control, please refer to the solar controller manufacturer for further information. Option B. Where the solar controller and hydraulic system demonstrate that by no lesser means the requirement in Option A is satisfied by other means; certification by an approvals body is required to demonstrate that in the event of the stored water going over temperature, the heat input to the cylinder is isolated by physical means and is non self resetting. These systems should be clearly identified with reference to the approvals body. (See Note 2) Note 1 :Whilst most solar cylinders use a coil type heat exchanger other options such as external plate to plate devices , external annulars or ‘tank in tank’ systems may be used but the same control options always apply. Note 2 :Current approved bodies include the British Board of Agrement (BBA) , WRc-NSF Limited, or KIWA 3.4 colD wAter supply The strainer prevents any debris entering the other controls. The pressure reducer ensures the correct operation of the expansion vessel, and prevents any damage to the control valves through too great a pressure. The non-return valve ensures the water expansion is forced into the expansion vessel and prevents contamination of the mains cold water supply. The expansion relief valve will discharge expanded water to the discharge tundish if the expansion vessel fails. It is important to ensure that the cold water main is capable of supplying the increased demand which will be imposed on it. Hot and cold water are both drawn off the same source of supply. Remember, there will not be a storage tank to help compensate for variations in the demand on the system. 5