4. Indicator lampsThe heating and c

4. Indicator lampsThe heating and cooling unit is controlled fully automatic via the temperature controller. The operating status and malfunctions are indicated by indicator lamps.» The green lamp indicates the proper operating status i.e.it lights up when the expansion tank is full and the circulation pump is operating. The expansion tank is full when the water level in the expansion tank is between float-operated switches (b) and (c)(See fig. 4-1, item 3)» The red indicator lamp indicates a failure at the heating and cooling device. You get further informations about the cause of the malfunction on the display of the temperature controller. If there are more malfunction messages they will be scrolled one after another.5. Cabinet blowerA cabinet blower is built in to the front panel of the control cabinet for cooling the cabinet. The cabinet blower is switched on by the main switch of the heating and cooling device. On the blower there is a filter to clean the intake air. This filter must be cleaned or replaced periodically. The cleaning frequency depends on the environment and the degree of dirt.6. Analogue pressure gauge(See fig 4-1, item 11)Displays the system pressure of the closed circuit produced by interaction of the header pressure and the temperature.7. Shut-off valve(See fig 4-1, item 24)This serves to close off the compressed-air feed.8. Pressure controller(See fig 4-1, item 26)Pressure reducer for adjusting the compressed air pressure in the supply pipe.9. Expansion tank air release valve(See fig 4-1, item 5)This serves to bleed air from the expansion tank when starting up thesystem.10. Analogue pressure gauge(See fig 4-1, item 27)Displays the header pressure in the supply pipe as set by the pressure reducer.