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HVAC Pressure Switch

Pressure Range: 16Bar~47Bar
Adjustable Pressure Setting
One-piece interface welded bellows element
Fast rebound function, Low abrasion and Durable
High reliability electrical & mechanical performance

A digital thermostat is not the ideal solution for some refrigeration systems. When the compressor is started, refrigerant vapor transform into high-temperature high-pressure fluid and enter the condenser where most of the heat is rejected, the refrigerant flow leaves the condenser and arrive the evaporator there undergo a sharp temperature and pressure drop, the cold air will enter the refrigeration chamber, the refrigerant flow will be heated by the rejected heat and return to vapor. The low-pressure setting can be used to control the temperature because the pressure proportional related to the temperature in the refrigeration system. Hence, a simple mechanism will help in this area.


There are some advantages to LEFOO mechanical pressure switches. Electricity-free, Wiring is simplified and cost less when installed.

1. Some tips for LF55, LF58 pressure switch

Wrong install pressure switch relief valve between the bottom manifold and pressure switch itself will cause back pressure and pressure leakage. There is a diaphragm(0.15mm tin bronze disc)and a Nitrile rubber O-ring to seal the spring trigger. Be careful with the diaphragm when using a pressure switch on a fluid pipeline or liquid tank, because it's hard to mend pressure exactness after the liquid leak into the pressure switch. Inside the spring is a threaded galvanized iron stud that will trigger a nylon PA66 covered electric bridge (durability of 100 thousand times).


2.The cut-in and the cut-out pressures setting

Cut in and cut out pressures will mechanical control the work time when a pressure switch is installed. Usually, it is advantageous to keep the refrigerating system work a long period and rest a long interval for energy efficiency.


To set cut in and cut out pressures need to know

  1. The lowest temperatures of refrigeration chamber or chilling room.

  2. The temperature difference between the chamber temperature and the refrigerant temperature in the evaporator.

  3. Start time and temperature boost range of the compressor.

  4. The pressure differences at the evaporator output and the compressor input.