User manual HONEYWELL NA 225-A

[. . . ] 5 seconds and 10 hours (set at 10 minutes during manufacture) Cut-in pressure: 2. 0 bar (a pressure reducing valve must be fitted before the refilling unit for pressures above 4. If the system pressure falls to below the lower set value, then an electrical impulse opens the changeover valve 3 above the pressure switch 8 and thereby permits fluid flow to the backflow preventer. [. . . ] If the inlet pressure falls to the set pressure of the backflow preventer 5 during the automatic refilling operation, then the backflow preventer automatically goes to the shutoff position (open to atmosphere). Changes over to the flow position only when the downstream system pressure falls below the lower set limit on the pressure switch 8 6 Connector strip - For connecting the individual electrical components 7 Viewing window for indicating the operating position of the backflow preventer (green visible = shutoff position) 8 Pressure switch - for changing the cutin and cut-out pressures (lower and upper limits), so that they can always be set to suit the system pressures. See section 10 for further information on setting options 9 Discharge tundish - for carrying away small quantities of water during the changeover operation. connection for DN 40 plastics pipe 10 Time relay - To permit time limitation of the filling cycle. Variable time settings from 5 to 100 minutes filling time 11 Pressure gauge - indicates the inlet pressure of the supply mains 12 Cable connection for electrical supply to the automatic refilling unit 13 Wiring centre 14 Drain valve - required for setting of the pressure limits Assembly and commissioning must only be carried out by specialists according to regulations and codes of good practice. Fit appliance with flow in direction indicated 2. make connections to the inlet main water supply and to the system. To enable subsequent service work and simplify setting of pressure limits, shutoff valves should be fitted on both sides of the appliance. The pressure switch is set during manufacture to the following values: Cut-in pressure: 2. Alteration of the cut-out pressure also causes the cut-in pressure to be changed. The differential pressure increases at higher pressure settings. The maximum cut-out pressure must be lower than the opening pressure of the safety valve fitted to the system. Any adjustment of the settings can only be made with the system in operation. The adjuster screw is turned clockwise for increasing the pressure setting and anticlockwise for reducing the pressure setting. Einstellschraube Adjuster screw for cut-out pressure (SA) The time relay is set during manufacture to setting which corresponds to a time duration of approximately 10 minutes. If it is required to change the time period, the DIP switches should be set according to the following: 1 Slightly open the drain valve 14 so that the pressure indicated on the pressure gauge reduces. [. . . ] 4 After setting the pressure switch, close drain off valve 14 and open shutoff valve 2 . If the cut-out pressure is not reached, this can be caused by the following: G The time period setting for the appliance is too short for the cut-out pressure to be reached. G There is a leak in the heating or cooling system which prevents the cut-out pressure being reached. [. . . ]