Breathers are available in a variety of styles, materials and
sizes. Breathers provide clean airflow into reservoirs and other
storage containers where there is an exchange of air during changing
fluid levels. In high moisture environments or applications with
large changes in machine attitudes, breather caps with pressure
relief and vacuum breakers limit air exchange and provide a positive
suction head at the pump inlet.
Change the filter after each 500 hours of operation. More frequent
replacement may be required when operating in heavily contaminated
areas, and on mobile equipment. Under such conditions, Donaldson
recommends replacement every 250 hours
To accurately monitor the oil level in your tanks and reservoirs,
choose Donaldson level gauges. Three models indicate oil level and
temperature, 35º to 210ºF (30º to 90ºC). Two
models indicate oil level only.
Transparent lens material is protected by metal bar with BunaN
Maximum working pressure for all models is 14.5 psi / 1 bar /
100 kPa for pressurized tanks.
Recommended bolt tightening torque is 10 lbs-ft, with inside nut
for tightening directly on the tank.
Suggested mounting hole diameter: 11mm or 13mm.
Removable 500µm mesh strainer. (Except model P171848, which
has a nonremovable strainer.)
10µm air breather/filter.
Models P171855 & P171848 include drilled flanges with attaching
screws. P171856 without pre-drilled holes P171859 with weldable
How They Work
As fluid levels rise and fall inside the reservoir, air flows
in and out through the strainer and breather as shown below. The
breather filter inside the cap removes contaminants as small as
10µm from the air to keep airborne contaminant from entering
the fluid. The strainer removes large particles from fluid as it
is added to the reservoir.