Pressure Relief Valve on an Air Dryer leaks

Probably is not leaking but doing what its supposed to do: relieving pressure.
Is the truck building pressure on the tanks?

 

Probably a blockage either in the drier cartridge, or in the air line between cartridge and tank.

 

No, remove the air line between drier and tank and see if it's plugged.

 

Bypass the dryer and see if it builds. Connect air in and air out together. If it does, you need a new dryer.

 

What's the rating on the relief valve? They come in several ratings.

 

Those air dryers are the worst I have the twin cartridge one on the Mack I drive. As soon as it gets below freezing it freezes up and either that relief valve leaks or the purge valve leaks. Not to mention it sounds like an airplane taking off when it does pop off.

Do you have any water at all on your air cans? As soon as I get the slightest bit of moisture in mine is when the problems start. And I drain mine every day