TM 9-4520-272-14&P
FIELD (UNIT) MAINTENANCE
LARGE CAPACITY FIELD HEATER (LCFH)
NSN 4520-01-500-1534
FLAME SENSOR
INSPECT, TEST, REPLACE
INITIAL SETUP:
Tools
Personnel Required
Tool Kit, General Mechanics (Item 2, WP 0092
MOS 63J or 52C
Materials/Parts
Equipment Condition
Rags, Wiping, Clean (Item 4, WP 0119 00)
Heater shut down and cool.
Main battery switch OFF and handle removed
Burner access door open.
INSPECT
1. Inspect the flame sensor wiring harness (1) to ensure that the wires are not damaged in any way and
that the insulation has not been scraped away. Ensure that the connector (2) is firmly engaged.
2. Loosen clamp (3) and remove flame sensor from flame sensor tube (4) attached to burner head.
3. Inspect glass face of flame sensor. If dirty, wipe with clean soft cloth.
4. Install flame sensor (5) in flame sensor tube (4) attached to burner head and tighten clamp (3).
TEST
1. Remove flame sensor (5) from flame sensor tube (4) attached to burner head by loosening clamp (3).
2. Disconnect flame sensor connector (2).
3. Connect multimeter test leads to blue and white flame sensor leads (1). Set multimeter to read
resistance.
4. Hold open end of flame sensor (5) towards a light source (a 60 watt light bulb or direct sunlight). The
resistance indicated on the ohmmeter should be low.
5. Block off light completely by covering the open end of the flame sensor (5). Within 10 seconds the
resistance indicated should be high.
6. Replace flame sensor (5) if there is no change in resistance during this procedure.
7. If flame sensor (5) meets above tests, install flame sensor from flame sensor tube (4) attached to
burner head by tightening clamp (3).
0053 00-1
