To judge whetherthe pressure switch is good or bad, the multimeter can be used to measurewhether the high-voltage protection switch is on or not. If theair-conditioning equipment high-voltage protection, you can refer to thefollowing reasons:

1. Theexternal fan turns slowly

   Maintenance method: air-conditioning fanoutside because of rust or stuck and so on slow the speed of the wind. Clean upthe foreign matter of the air-conditioning fan bearing, and put some lubricanton the fan shaft to restore the fan speed. In addition, the presence of air inthe system

Theoutside is covered with something

The air-conditioning unit placed aroundSundries or covered with things, so that the air-conditioning unit can not benormal heat dissipation. Maintenance method: Don't put sundries around theoutside machine of air conditioner, and don't cover things on the outsidemachine.

Too muchrefrigerant 

Excessive refrigerant will also make theair-conditioning internal pressure is too large, leading to high-pressureair-conditioning maintenance methods: As long as the release of excessrefrigerant can be solved.

Theambient temperature is too high                                                                                                                                              When the outsideenvironment reaches 43 degrees of high temperature, air conditioning heatingwill appear the phenomenon of heat dissipation difficulties, then the airconditioning will appear high pressure protection, when the outdoor airconditioning is difficult to work above 43 degrees, only temporarily do notturn on the air conditioning

Controlloop anomaly                                                                                                                                                              When the control circuit ofthe air-conditioner is out of order, the air-conditioner can not work normally,which leads to the increase of the internal pressure, at this time there willbe protection. Check the control circuit where there is a problem, thereplacement of the corresponding parts can solve the problem.

Otherreasons: 

 Outside the machine installed in poor heatdissipation environment, such as narrow stairwells, billboards behind, Grilleinside and so on.                                         In the summer, the equipment has been running at high temperature,in fact, the factory laboratory to do experiments, the outdoor environmenttemperature up to 50 °C, the equipment can runnormally, once the equipment continues to run at high temperature, it can notrun normally until the real high-pressure protection;                                                                                                                                                                     High pressure protectionvalue of R410a refrigerant reference: 4.2 MP (43kgf/cm)  

The high pressure protection value of R22refrigerant is 2.65 MP (26.5 KGF/CM) 

The return air space of outdoor units, ina narrow air-conditioning unit inside, only the outside Fan Cooling air outletarea is far from enough, in order to meet the return air (air inlet) space ofequipment, how big the condenser is, how big the return air area is, if thereturn air part of the grid shelter, please also remove, in order to ensuregood ventilation equipment.