L.B. White I-34 Infraconic Spark Ignition - Manual (Page 17)

TERMINAL
MOUNTING LEG
RESET BUTTON
SENSING SURFACE
FLAME
■ This heater is equipped with a manual reset high limit
switch. Its purpose is to disconnect the electrical
supply to the ignition control board in the event of an
overheat condition.
■
An overheat condition is normally caused by:
-- Excessive fuel gas pressure.
-- Heater not being routinely cleaned.
-- Heater not properly hung. (See page 8.)
The high limit switch should be tested a minimum of once
a year or anytime the heater is taken down for servicing.
Refer to the following testing instructions.
1. Remove the high limit switch from the control box.
2. Apply a small flame only to the sensing portion on the
back of the switch. BBee ccaarreeffuull nnoott ttoo m meelltt tthhee ppllaassttiicc
hhoouussiinngg ooff tthhee sswwiittcchh wwhheenn ccoonndduuccttiinngg tthhiiss tteesstt..
4. Within a minute, you should hear a pop coming from
the switch, indicating the contacts of the switch have
opened.
5. Allow the switch cool down before firmly pressing the
reset button.
6. Check for electrical continuity across the switch
terminals.
7. Reinstall the switch back into the heater.
FIG. 15
HIGH LIMIT SWITCH
W WAARRNNIINNGG
FFiirree HHaazzaarrdd
■ Do not operate the heater with the high limit switch
bypassed.
■ Operating the heater with a bypassed high limit switch
may lead to overheating, possibly resulting in a fire,
with subsequent damage to the heater and building,
or loss of livestock.
1166
d. Position the tool between inner cone and ignitor
tip. See Fig. 14c.
FIG. 14c
e. If the gap exceeds the minimum to maximum
tolerances of the tool, reset the gap:
-- loosen igniter mounting screws.
-- reposition the igniter assembly until the
gap is within the proper tolerances.
f. Tighten the igniter mounting screws.
INNER
CONE
TOOL
.175 GAP BETWEEN
ELECTRODE AND CONE