TM 9-4520-257-12&P 0041 00
OPERATOR AND UNIT MAINTENANCE
H-45 LARGE RADIANT SPACE HEATER
(TYPE I, SOLID FUEL)
(TYPE II, LIQUID FUEL)
MAINTENANCE ALLOCATION CHART, INTRODUCTION
THE ARMY MAINTENANCE SYSTEM MAINTENANCE ALLOCATION CHART (MAC)
This introduction provides a general explanation of all maintenance and repair functions authorized at
various maintenance levels under the standard Army Maintenance System concept.
The MAC (immediately following the introduction) designates overall authority and responsibility for the
performance of maintenance functions on the identified end item or component. The application of the
maintenance functions to the end item or component shall be consistent with the capacities and
capabilities of the designated maintenance levels, which are shown on the MAC in column (4) as:
Unit includes two subcolumns, C (operator/crew) and O (unit) maintenance
Direct Support includes an F subcolumn
General Support includes an H subcolumn
Depot includes a D subcolumn
The tools and test equipment requirements (immediately following the MAC) list the tools and test
equipment (both special tools and common tool sets) required for each maintenance function as
referenced from the MAC.
The remarks (immediately following the tools and test equipment requirements) contain supplemental
instructions and explanatory notes for a particular maintenance function.
Maintenance functions will be limited to and are defined as follows:
1. Inspect. To determine the serviceability of an item by comparing its physical, mechanical, and/or
electrical characteristics with established standards through examination (such as by sight, sound, or
2. Test. To verify serviceability by measuring the mechanical, pneumatic, hydraulic, or electrical
characteristics of an item and comparing those characteristics with prescribed standards.
3. Service. To perform operations required periodically to keep an item in proper operating condition
(such as cleaning; decontaminating, when required; preserving; draining; painting; or replenishing fuel,
lubricants, chemical fluids, or gases).
4. Adjust. To maintain or regulate, within prescribed limits, by bringing into proper or exact position, or
by setting the operating characteristics to specified parameters.
5. Align. To adjust specified variable elements of an item to bring about optimum performance.
6. Calibrate. To determine and cause corrections to be made, or to be adjusted on instruments, tests,
measuring, and diagnostic equipment used in precision measurement. This consists of comparisons
of two instruments, one of which is a certified standard of known accuracy, to detect and adjust any
discrepancy in the accuracy of the instrument being compared.