held in place by fastener 35 and the joint is sealed by o ring seal 36 and can be disassembled from the pump easily by removing the fastener 35 an electrode 40 mounts inside the pump along its center axis by an insulating lead through 41 and connects to an igniter 23 by means of the igniter lead 42 the igniter 23 may be a piezo electric igniter that does not require an external power source alternatively battery powered igniters or igniters powered by external electrical sources may also be used the electrode 40 fits through a bore 44 of an insulator 39 that is mounted centrally on the flame holder 37 the insulator may be an insert made of electrically insulating material such as ceramic as shown in fig1 alternatively the flame holder 37 may be made of an electrically insulating material such as ceramic and the bore is integral to the flame holder 37 the tip 80 of electrode 40 passes through the insulator 39 and extends into the burner chamber 38 downstream of the flame holder 37 fig2 shows a burner chamber 38 of an embodiment of a heat gun 200 partially disassembled from the pump 202 by unscrewing the fastener 35 the burner chamber 38 can be readily removed from o ring seal 36 as the burner chamber 38 is removed from the pump 202 and o ring seal 36 the electrode 40 slides out of the insulator 39 note that fig2 shows the burner chamber 38 separating from the pump 202 before the electrode 40 fully separates from the insulator 39 this feature may ease assembly because it permits inserting the electrode.