The Mac Valve has an internal rubber plunger which opens and closes the ports which allows air to pass through to a cylinder, air pump etc.. The following can cause the plunger to stick: 


  • Moisture -- It is important to make sure you have a refrigerator dryer inline with your compressor.  The dryer is used to eliminate any moisture out of the air lines.  It is also recommended to have an additional Filter before the air gets introduced to the mac valve.  In these cases we will use an FRL (Filter Regulator Lubricator)
  • Using the incorrect lubricant in the lubricator bowl (FRL) -- Using the incorrect lubricant, like WD40 and other similar oils, in the lubricator bows can cause the seals/rubber in the mac valve to swell and get damaged. 
  • Debris -- Debris in the lines can cause the plunger to stick.  Open the valve carefully and flush out any debris out of the valve body. You can use air to clean the valve ports and body.


NOTE: Mac Valve recommended lubricants.


Manufacturer                        Oil Number

NFO                                    NFO 10 H/NR

NFO                                    NFO 10 W/NR

Chevron                              AW10 Machine Oil

Chevron                              Handy Oil - 15

Exxon                                  Teresstic 32

Mobil                                  Mobil DTE Light

Mobil                                  Dexron II ATF

Mobil                                  AFT 210 Type F

Mobil                                  DTE 13M

Mobil                                  Almo 525

Mobil                                  Mist Lube 24

Mobil                                  DTE 24

Mobil                                  Hydraulic Oil 13

Mobil                                  Hydraulic Oil AW 32

Wolverine                           A-Industrial 150 R&O

Titan                                    Type F ATF

Tital                                     Dexron II ATF

American                             Industrial Oil 32