Service Instructions - Piper APACHE PA-23-235 Service Manual

2-67. SERVICE INSTRUCTIONS. The induction air filters should be cleaned
every 50 hours or sooner depending upon operating conditions.
Filters should
be rejected for use if the paper filter material is torn or ruptured, or the housing
is damaged.
The filter gasket should have no tears and be securely positioned
in place.
a. The cartridge type air filters should be cleaned by the following procedure:
1. Remove filter, inspect, and clean by tapping it against a hard surface
to remove grit, sand and dirt. (Do not blow out with an air hose, soak in oil, or
cleaning fluid.)
2. If the filter is found to be in good condition and is not obstructed after
being properly cleaned, reinstall filter.
b. The panel type filter installed only on airplanes equipped with turbocharging
units may be cleaned by one of two basic methods, the compressed air method
and thewashingmethod.
The compressed air method is effective when the major
contamination on the panel is dust.
The washing method is effective on carbon,
soot and oil laden filters.
Accumulation of exhaust soot (fine carbonparticles)
collects on the filter and causes a rapid increase in restriction or short filter
life. For best results,
visually determine condition of filter and choose either
method.
This choise will also depend on the availability of the cleaning equip-
ment.
1. The compressed air method of cleaning the filter is as follows:
(a) With the filter removed, direct a jet of air against the downstream
or clean air side of the filter (opposite to normal airflow).
(b) Move the air jet up and down the pleats, moving air jet over the
complete filter.
(c) Nozzle pressure must not exceed 100 psi and be kept at least one
inch away from filter.
Take care that the paper is not ruptured by
the nozzle or air jet.
2. The washing method of cleaning the filter is as follows:
(a) If compressed air is available, blow the filter as given in (a).
(b) The filter can be cleaned by washing in a good non-sudsing deter-
gent or the filter manufacturer's
cleaner D-1400. Mix two ounces
of D-1400 to one gallon of water.
(c) Soak filter in solution for 15 minutes, then move filter back and
forth about two minutes to free filter of dirt deposits.
(d) Rinse complete filter in a stream of water until rinsewater
is clear.
(Maximum water pressure 40 psi.) A good thorough rinse is very
important.
(e) Dry filter thoroughly before re-using.
Do not use light bulbs or ex-
treme heat for drying.
HANDLING AND SERVICING
Reissued: 2/18/81
1D23
*PIPER AZTEC SERVICE MANUAL