L.B. White Oval 90 v.2 Owner's Manual And Instructions page 19

Igniter
The tip of the igniter is exposed to a harsh environment
consisting of high temperatures and combustion
products. Periodic servicing is required.
A. REPLACEMENT
1. Remove igniter mounting screws. See Fig. 15.
2. Lift and pivot the igniter until it clears the burner.
See Fig. 16.
DO NOT FORCE OR BEND THE IGNITER
DURING IGNITOR REMOVAL. DO NOT
FORCE OR BEND THE BURNER VANES
(SENTINEL) DURING IGNITER REMOVAL.
FIG. 15
SCREWS
FIG. 16
BURNER VANES
Oval Radiant Tube Heaters
Owner's Manual • Oval Radiant Tube Heaters
3. Pull the igntion cable's rubber boot from the igniter.
B. MAINTENANCE
1. Ensure the gap is 1/8 in. See Fig.17.
2. Clean the electrode and ground rod using emery
cloth.
3. Ensure the insulative base of the electrode is not
cracked.
FIG. 17
ELECTRODE
19
GAP
(1/8 IN.)
GROUND ROD