99M90
21-40-01
Page: 5-3
Rev. New
Issued: May 9, 2012
I-Series Combustion Heater
Owners Manual
5.3
Periodic Inspection Checks (cont’d)
500 Hours time in service and each 500 hours thereafter
(
or 60 months, the first to occur).
Inspection shall be conducted on all I-Series heaters (including new, rebuilt, upgraded,
or overhauled). The 500 Hour Inspection coincides with the requirements of the 100 hour
inspection plus the
following checks and inspections:
1.
Perform the Pressure Decay Test per the instructions contained in P/N 99M91
Overhaul & Maintenance manual. Failure of the Pressure Decay Test requires
heater overhaul prior to next use.
2.
Replace the spark plug and fuel nozzle.
3.
Replace brushes and bearings in the. combustion air and ventilating air blower
motors. If sealed motor, replace motor.
1000 Hours time in service
(or each 60 months the first to occur).
(
The 500 Hour Inspection coincides with the requirements of the 100 hour inspection
.)
1.
If installed, disconnect the external fuel shutoff valve, apply fuel pressure and
check that the valve shuts off fuel completely. Internal fuel shutoff, check for fuel
pressure drop with solenoid shutoff and accompanying fuel drip from heater
drain. (Power on to flow fuel.) These components are replacement items only.
2.
If installed, disconnect the fuel regulator and shutoff valve, apply fuel pressure
and check that the valve shuts off fuel completely. Check regulation pressures
per Chapter 9 of the
P/N 99M91 Overhaul & Maintenance manual
. If checked,
note that no local overhaul or repair on these components are permitted. Some
units may be returned to HET for overhaul or exchange.
It should be noted that
these regulators contain age controlled components that are subject to the
requirements of MIL STD 1523.
2000 Hours time in service*
(or if the pressure decay test fails, first to occur).
1.
Overhaul or replace heater assembly.
* Upon the accumulation of 12 calendar years from new, rebuilt or from any
overhaul, the combustion heater must be overhauled regardless of hours time
in service.
