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Extreme Humidity Desiccant Breathers (EX Series)

The perfect solution for high humidity and high dust environments.

In certain extreme operating environments such as paper mills or a steam cleaning rooms, the humidity level far exceeds normal industrial environments. In these situations, lubricants and other fluids stored in tanks and reservoirs need the protection of a desiccant breather even more. However, small temperature variations draw in the humid air and unnecessarily reduce the life of the breather. The Watchdog® Extreme Humidity Breathers incorporate two check valves, one to control airflow into the protected reservoir, and one to control airflow out. The check valves provide a closed system until airflow is required, extending the service life of the desiccant. Specifically, the intake check valve allows airflow into the breather only when differential pressure between the atmosphere and fluid reservoir exceeds a 0.1 psi threshold, while the exhaust check valve permits air to exit the reservoir when the differential pressure exceeds a 2.0 psi threshold. A 0.1 psi check valve is also available for exhaust. The end result is longer desiccant life by allowing the air to flow through the breather only when needed to protect the integrity of the tank.

Unlike a membrane system, which does not allow internally generated gases and contaminants to exit the system, the Watchdog® Extreme Humidity Breather offers all of the advantages of breathing air in and out of the tank while removing water vapor and solid particles before they contaminate the fluid.

Typical applications include:

  • Paper Mills
  • Wash-Down Areas
  • Steam Cleaning Rooms
  • Mine Quarries


  • Water Vapor Adsorbent – The silica used in the Watchdog® Extreme Humidity Breathers adsorb up to 40% of its own weight
  • Color Indicating – When maximum adsorption is reached the silica gel turns from orange to dark green, indicating replacement is needed. The silica gel used is chemically inert, non-corrosive, and does not contain cobalt chloride, a heavy metal. The color changing dye used is environmentally safe and meets all health and safety requirements.
  • Durable Construction – Watchdog® Extreme Humidity Breathers are manufactured from rugged ABS plastic and impact modified acrylic.
  • Easy Connection – Models are available with 1″ slip fit connection which mates with the standard Watchdog® Breather Adapters or with a 2″ male NPT connection.


Model No. Description Air Flow Water Capacity Dim A Dim B Dim C Check Valve Capacity
39110 Extreme Humidity 10 CFM .2 lb 6.25 in N/A 1/2" FNPT 3 psi in / .3 psi out
39111 Extreme Humidity 20 CFM .6 lb 5 in 1.25 in 1" slip .3 psi in / 2.1 psi out
39112 Extreme Humidity 20 CFM 1.4 lb 8 in 1.25 in 1" slip .3 psi in / 2.1 psi out
39113 Extreme Humidity 20 CFM .6 lb 5 in 1.87 in 2" MNPT .3 psi in / 2.1 psi out
39114 Extreme Humidity 20 CFM 1.4 lb 8 in 1.87 in 2" MNPT .3 psi in / 2.1 psi out

Replacement Cartridges

Model No. Description Replacement For
39217 Replacement Cartridge 39110
39218 Replacement Cartridge 39111
39219 Replacement Cartridge 39112
39310 Replacement Cartridge 39113
39222 Replacement Cartridge 39114


Nominal Air Flow Rate 10 CFM (75 gpm of fluid volume change)
20 CFM (150 gpm of fluid volume change)
Operating Temperature Range -20ºF to 200ºF (-28ºC to 93ºC)
Material ABS plastic and impact-modified acrylic
Particulate Filtration Level 2 Micron Filter
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