Came out today for a no ac call and to perform preventative maintenance for a Lennox system model #xc16-048-230-02, serial #5810k04676. Upon inspection I found that the thermostat was calling for ac, the blower would start but the condenser would not start. I noticed that the contactor was not engaged so I tested the voltage at the contactor and got a reading of 0. I tested the voltage at the control voltage wire coming out of the house and got a reading of 26volts. I bypassed the high pressure switch and the system started right up. The reset button for the high pressure switch is completely missing (see photo). Recommend replacing the high pressure switch. Performed preventative maintenance for a high efficiency Lennox system.the evaporator coil’s are clean and in good condition. Tested the drain pan, drain line and condensate pump with several cups of hot water to ensure that there are no leaks or clogs. The pure air kit has been ordered and Chud will need to return to install once