TM 9-2320-361-34 17-20. FUEL BURNING PERSONNEL HEATER TESTING (Contd) d. Flame Detector Switch Test 1. Place switch (4)in START position. NOTE Purge time is the interval from turning control box switch to OFF position until indicator lamp goes out. 2. Place switch (4) in OFF position and record purge time. Burning should stop within thirty seconds and blower motor (9) should continue to run up to three minutes. If purge time exceeds three minutes, replace or adjust flame detector switch (6) (para. 17-15). Place switch (4) in OFF position. I e. Overheat Switch Test 1. Place switch (4) in START position. 2. When indicator lamp (5) illuminates, place switch (4) in RUN position and allow heater (10) to operate for one minute. 3. Partially restrict air inlet with a sheet of cardboard or sheet metal. Overheat switch (11) should activate and shut down heater (10) within five minutes. 4. If heater (10) does not shut down after five minutes, replace overheat switch (11) (para. 17-17). I f. Test Equipment Removal WARNING Allow time for heater to cool before removing from test equipment. Failure to do so may result in injury to personnel or damage to equipment. 1. Close fuel shutoff valves (1). 2. Disconnect lead (2) from power source (3). 3. Remove heater (10) from test equipment. 4. Place guard (7) on heater (10) and turn two dzus fasteners (8) to secure. 17-60