The coolant is now isolated in the reserve. Now you can intervene on other points of the system, from the filterto the low pressure part of the compressor. 7.5 - THERMOSTATIC EXPANSION VALVE 7.5.1 – VALVE IS LOCKED SHUT The thermostatic valve automatically adjusts the flow of liquid coolant in the holding plate circuit according to thetemperature reached by the latter. The quantity of coolant flowing in the plate must be enough to evaporate completely in the plate circuit. For this reason the valve closes according to the temperature reached by the plate. The thermostatic valve is very reliable and only in very rare cases causes problems. Therefore, before attributing the cause of the breakage or circuit interruption to the thermostatic valve, check that the couplings are screwed as far as they possible. If this check is negative, the thermostatic valve is probably defective. When the valve is closed and the coolant flow stops, two situations may occur:A) The valve is temporarily locked as described in 7.2.1 due to humidity. B) Permanent valve lock caused by breakage, described below. In case ‘A’ (more probable), the only solution is to change the filter (see 7.6). A defective valve, as described in ‘B’, is permanently shut and the system no longer functions. 7.5.2 – BREAKAGE OF THE THERMOSTATIC EXPANSION VALVE CAPILLARY TUBE If the copper capillary tube exiting from the valve breaks, the valve will be locked shut. Replacement is required. 7.6 – REPLACING THE DEHYDRATOR FILTER Proceed as described in point 7.4. Unscrew the couplings completely to remove the filter, but do not remove theprotections on the new one until it is ready to be connected to the system. When you connect, screw the couplings completely. Write the date of the operation on the new filter. IMPORTANT NOTE: The (A070600) is mounted on the compressor site (liquid batch) and from on the side ofthe holding plate. 7.7 – REPLACING A PRESSURE SWITCH 7.8 REPLACING THE THERMOSTAT Automatic pressure switches (HP and LP) supplied with the produce are screwed on a ¼” male SAE. Thecoupling is equipped with a SCHRADER valvelet, which closes automatically when the pressure switch is unscrewed. To unscrew the pressure switch, use a 14 key on the pressure gauge’s brass hexagon, and second key (CH 12) to keep the coupling still from ¼ SAE. A sealant provides an adequate seal, and you will need to spread the coupling thread with LOCTITE 542 before rescrewing the spare part (cod. H09). Then tighten with key and second key. If the spare part is not immediately available, remember that the valvelet of the coupling on the reserve does not guarantee a seal and can drain the system if left without cap. To replace the thermostat, remove the adjustment knob and the screws fixing the casing, then remove theelectrical connections and unscrew the screws fixing the base of the thermostat. Assemble the spare part, inversing the previous operation. Unthread the bulb of the defective thermostat of the fixing plate to the plate after loosening the nut, thread under the bulb of the new thermostat and tighten the nut, checking that the bulb is positioned well and is in contact with the plate. Then adjust the new thermostat (point 7.1). 16