Suggested Setup For Heater Operation Test - Piper Navajo PA-31 Service Manual

391
VENTILATING
Figure 13-33. Suggested Setup for Heater Operation Test
13-49. TEST PROCEDURE.
13-50. GENERAL INFORMATION. A test of all components should have been made after overhaul to
insure proper operation. Some shops may not have complete testing facilities for measuring airflows,
pressure drops and other factors which would be accomplished in a laboratory-type test. If such a test
cannot be made, install the heater and check operation on the ground and in the air to determine if
operation is normal In shops where complete test equipment is available and a complete functional test can
be performed, the test routine described in subsequent paragraphs should be made.
13-51. EQUIPMENT REQUIRED. (Refer to Figure 13-33.)
a. An improvised stand to hold the heater during test. The heater should be located far enough
away from any combustible material or atmosphere to avoid hazard. A location should be chosen where
exhaust can be dispelled. Do not add an excessive extension to the heater exhaust.
b. A source of fuel capable of being regulated at 7.5 ± .5 psi.
c. The combustion air blower to be used with the heater should be used for the test.
d. A 24-volt current supply, which may be a dc generator with a rheostat, ammeter and voltmeter in
the line to control and indicate the current draw and voltage output.
e. Two water manometers (zero to 5.0 inch water column) for measuring the pressure in the
ventilating air duct and in the combustion air stream.
f. A piece of duct to be attached to the downstream end of the heater. It should have a minimum
length of 24 inches and the same diameter as the heater being tested. A 2.25 inch diameter orifice should be
centrally located at the outlet end. An aperture should be provided for the thermometer and duct switch
and a static tap should be attached as shown in Figure 13-33.
g. A thermometer with 500°F scale.
h. A fuel-pressure gauge.
i. A controlled source of compressed air for final leakage test.
Reissued: 10/12/79
HEATING AND VENTILATING SYSTEM
PIPER NAVAJO SERVICE MANUAL
5D9