Exhaust Gas Temperature Gauge Cleaning And Inspection - Piper PA-44-180 SEMINOLE Maintenance Manual

ANALYZERS.
EXHAUST GAS TEMPERATURE GAUGE.
This dual instrument, which is commonly referred to as EGT, is used to aid the pilot in setting the most
economical fuel-air mixture for cruising flight at a power setting of 75% or less. It is a sensing device which
monitors the temperature of exhaust gases leaving the engine cylinders. If it is found defective after checking
with the troubleshooting chart, it should be replaced. If the leads to the gauge are defective in any way, they must
be replaced. When replacing leads, it is necessary to use the same type and length of wire, because the resistance
of the leads is critical for the proper operation of this gauge. When troubleshooting this instrument be certain the
system being checked coincides with the system selected on the indicator.
CLEANING AND INSPECTION.
Unless mechanical damage is evident such as broken glass, bent or broken pointer, or broken case, the
following checks should be performed before removing the instrument:
1. Remove probe from exhaust stack and check for broken weld (at tip end) or burnt off end. Measured
resistance of probe should be .8 ohms. Clean the connections with steel wool before reassembly.
2. Disconnect lead wires at instrument and measure length and diameter. Resistance with lead wires connected
to probe should be 3.3 ohms. Clean connections with steel wool before reassembly.
3. With leads connected to instrument, heat probe with propane torch to dull red. The meter should read up to
the fourth graduation or approximately 1500° F. Before making this check, make sure that the adjustment
screw, which is located in the rear of the instrument case, is in the center of its travel. If this screw has been
turned to either end of full travel, it will shut the instrument off and no indication will be shown on the
pointer. If meter still does not read, replace it.
DO NOT CONNECT OHMMETER ACROSS METER. IT WILL BURN OUT
THE MOVEMENT OF THE METER.
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
— CAUTION —
3H13
7 7 - 3 1 - 0 2
Page 77-11
Revised: May 15, 1989