connect at pressure connection on coil inlet
assembly.
(4) Connect
electrical
leads
to
switch
terminals.
(5) Replace switch cover.
(6) Replace front fire panel and electrical
control box cover.
5-40. Low Oil Pressure Switch (Refer to Fig C-
13)
a. Removal. To remove the low oil pressure
switch proceed as follows:
(1) Remove front fire panel and electrical
control box cover.
(2) Remove switch cover.
(3) Disconnect electrical leads at switch
terminals.
(4) Disconnect switch sensing connections to
switch bellows assembly.
(5) Loosen
two
electrical
control
box
mounting bolts at rear panel (panel with fuse).
(6) Remove two electrical control box
mounting bolts on front side of box (below flame
safeguard and low water pressure switch).
(7) Pivot control box out from unit chassis to
gain access to oil pressure switch mounting screws
at back side of box.
(8) Remove the two oil pressure switch
mounting screws.
(9) Remove the oil pressure switch from the
box.
b. Installation. To install the low oil pressure
switch accomplish the procedures in paragraph 5-
40a, steps (1) through (9) in reverse order.
5-41. Low Air Pressure Switch (Refer to Fig
C-13)
a. Removal. To remove the low air pressure
switch proceed as follows:
(1) Remove electrical control box cover.
(2) Remove switch cover.
(3) Disconnect electrical leads at switch
terminals.
(4) Disconnect switch air sensing connection
at switch diaphragm.
(5) Remove two nuts and lockwashers on
bottom side of control box.
(6) Remove switch from control box.
b. Installation. To install the low air pressure
switch accomplish the procedures in paragraph 5-
41a, steps (1) through (6).
5-42. Excess Temperature Switch (Refer to Fig
Fig C-13)
a. Removal. To remove the excess temperature
switch proceed as follows:
(1) Remove front fire panel and electrical
control box cover.
(2) Loosen setscrew at bulb WEL on coil
outlet assembly and remove thermocouple bulb
WEL.
(3) Route thermocouple bulb and wire through
hole in back of electrical control box into box.
(4) Remove switch cover.
(5) Disconnect electrical leads at switch
terminals.
(6) Remove two switch mounting screws from
back side of box.
(7) Remove switch, thermocouple wire and
thermocouple bulb from box.
b. Installation. To install the excess temperature
switch proceed as follows:
(1) Align switch with mounting holes in box.
(2) Secure switch with two mounting screws,
insert screws from back side of box.
(3) Route thermocouple bulb and wire through
hole in back of box to bulb WEL on coil outlet
assembly.
(4) Insert thermocouple bulb and backing strip
in WEL. Secure with setscrews.
(5) Connect
electrical
leads
to
switch
terminals.
(6) Replace switch cover.
(7) Replace front fire panel and electrical
control box cover.
5-43. Flame Safeguard Relay Chassis (Refer to
Fig C-13)
a. Removal. To remove the flame safeguard relay
chassis proceed as follows:
(1) Remove electrical control box cover.
(2) Remove flame safeguard cover.
(3) Loosen two captive relay mounting screws
located at the top and bottom toward back of relay.
(4) When screws are free of relay mounting
base, remove relay from box.
b. Installation. To install the flame safeguard
relay chassis accomplish the procedures in
paragraph 5-43a, steps (1) through (4) in reverse
order.
5.44. Flame Scanner (Refer to Fig C-13)
a. Removal. To remove the flame scanner
proceed as follows:
(1) Perform procedure in paragraph 5-43a,
steps (1) through (4).
(2) Disconnect scanner leads at terminals S1
and S2 of flame relay terminal board.
TM 9-4940-342-14&P
41
