Abstract: AS PART OF A MONTH OLD SERVICE CONTRACT WITH A SUPERMARKET CHAIN, A JOURNEYMAN HVAC MECHANIC WAS SENT TO "START UP" VARIOUS PROPANE-FIRED HEATERS, INCLUDING TWO IN-LINE DUCT UNITS. BOTH WERE GLOW PLUG START UNITS (NO STANDING PILOT), WHICH HE DID NOT REALIZE. HE ALSO HAD NO MEANS OF "PROVING THE PILOT". SUCH "PROVING" WAS NOT REQUIRED WHEN THE UNITS WERE INSTALLED (ABOUT 10 YEARS AGO). HE WAS UNAWARE OF THIS. ALSO, THE INSTRUCTIONS FOR LIGHTING THE UNITS (PRINTED ON A PANEL DOOR) DID NOT EXACTLY FIT THEM. WITH THE MANUAL SELECTOR ON "PILOT", HE VAINLY ATTEMPTED TO LIGHT THE PILOT (WHICH WAS NEITHER NECESSARY NOR POSSIBLE WITH THE THERMOSTAT OFF). LEAVING IT ON "PILOT" (A MISTAKE) HE WENT INTO THE STORE AND TURNED THE THERMOSTAT FULLY ON. THIS OPENED THE PILOT GAS SOLENOID, BUT (UNKNOWN TO HIM) THE GLOW PLUG WAS EVIDENTLY INOPERATIVE. WHEN HE GOT BACK TO THE UNIT AND STRUCK A MATCH IN THE HOLE NEAR THE PILOT, THE ACCUMULATED PILOT GAS FLASHED, RESULTING IN MILD SECOND DEGREE BURNS ON THE FACE AND WRIST. MODERN PROPANE UNITS REQUIRE THAT IF THE PILOT DOESN'T "MAKE" IN 30 SECONDS, FOR WHATEVER REASON, THE ENTIRE UNIT WILL SHUT DOWN AND LOCK OUT. ALSO, THE APPARENT NEED TO LIGHT THE PILOT SHOULD HAVE BEEN A TIPOFF THAT SOMETHING WAS AMISS.