Piper SEMINOLE PA-44-180, Maintenance Manual

Page: 147 / 881

INSPECTION OF REMAINING COMPONENTS. (Refer to Figure 21-18)
1. Discard all rubber parts such as grommets, gaskets, etc. These items should always be replaced at
overhaul. Also discard the asbestos gasket.
2. Inspect all wires and wiring harnesses for damage to insulation, damaged terminals, chafed or cracked
insulation and broken plastic bands. Individual wires can be replaced by making up new wires from ~'o.
16 AWG stock and cut to correct length. It is advisable to use an acceptable crimping tool for installing
terminals rather than solder for all heater wiring connections. If wiring harness damage is visible, the
entire harness assembly should be replaced. If only one or more wires are damaged, cut the cable ties,
make up new wires, install them in the harnesses and restore all cable ties and clamps. If heater controls
were operating properly at the time of removal, reinstall them.
3. Inspect all hard parts consisting of bolts, screws, nuts, washers and lock washers. Replace damaged
parts.
4. The combustion air pressure switch must respond to delicate pressure changes and should always be
checked and/or replaced at overhaul. (Refer to Figure 21-17)
5. Replace the vibrator in the ignition unit at each overhaul.
6. Inspect the ignition assembly (refer to Figure 21-18) for dented case, loose or damaged primary terminal
insulator and broken or obviously damaged high voltage lead. Give particular attention to the condition
of the spring connector at the end of the lead. If the spring is burned off, visibly eroded or carbon
tracked, the ignition assembly should be replaced.
— Note —
Do not attempt a field repair of the ignition unit, as it is a sealed assembly.
7. Inspect the terminal strip for distortion and cracks and replace it if either condition exists.
8. Inspect radio/noise filters for short circuits by checking from either terminal to ground with an ohmmeter.
An open circuit reading should be obtained.
9. Inspect the spray nozzle with a magnifying glass for any obstructions in the nozzle orifice and any sign of
damage to the slight conical protrusion at the nozzle tip. Use compressed air to remove obstructions and
re-examine the orifice to make sure it is open. Exercise care when handling the nozzle to avoid pressing
or rapping on the tip face. Do not buff or scrape off deposits on the tip face. After cleaning, it is
advisable to store the nozzle in a polyethylene bag until ready for reassembly.
10. Replace the nozzle at overhaul.
— Note —
The nozzle can be spray tested by installing it in the holder and connecting the fuel
tube to a 7 psi fuel pressure source. The conical angle spray pattern should be even
and dispersed the same in all directions. Exercise caution to keep atomized fuel away
from fire.
11. Inspect the nozzle holder assembly for damaged threads at the fuel-tube fitting and for crimped or
cracked fuel line or distorted housing. Check the solenoid for continuity by connecting across each wire
lead with an ohmmeter. A reading of between 15 to 40 ohms should be obtained at room temperature. If
not within these limits, the solenoid should be replaced.
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
2 1 - 4 4 - 0 5
Page 21-36
Revised: May 15, 1989
1G3
PIPER AIRCRAFT