Cleaver-Brooks CBH 40 - Page 59

b) Release the scale lock. Remove the thumb
nut and the top set of cams.
c) Proceed with steps 'c' thru 'i' of preceding sec-
tion to get the high fire oil valve (HFOV) set-
ting on switch No. 1.
d) Place the second set of cams on the shaft.
Make sure that the operational cam's locking
screw is on the opposite side of the shaft as
the switch the cam is to operate (when the
scale plate is set near zero).
e)
Loosen both cam locking screws. Align the
two cam lobes so that only the operational
cam (silver colored) will cause switch lever
movement. Tighten the differential cam
screw.
f) Depress the scale lock. Turn cam so that the
cam roller of the No. 2 switch lever is exactly
over the outer corner of the operational cam
lobe when the scale indicates 60° or more of
SCALEPLATE
(BLACK SCALE)
OPERATING CAM
LOCKING SCREW
DIFFERENTIAL CAM
(BRASS)
OIL VALVE
SWITCH
(HFOV)
(
Chapter 5--Adjustment and Maintenance
motor travel. This switch is used to prove
damper opening during pre-purge. Connect
the leads into the circuit as indicated on your
wiring diagram. The yellow lead is not
required and its end should be insulated to
prevent a short circuit.
g) Check the operation of the switches under ac-
tual operating conditions. Make any
necessary cam adjustments to assure that the
oil valve opens at the desired point and that
the high fire switch makes when the damper
is open.
HIGH FIRE OIL VALVE SWITCHES -
CBH 50-100
Oil fired CBH boilers in sizes 50 thru 100 have two
adjustable cam actuated switches located at the
end of the jackshaft connected to the damper
motor. See Figure 1-6. Their purpose is to energize
INDEX
MARK
THUMBNUT
DIFFERENTIAL CAM
LOCKING SCREW
CAM
ROLLER
HIGH FIRE
SWITCH
(HFS)
SCALE LOCK
FIGURE 5-7. Q607B AUXILIARY SWITCH (TWO MICRO-SWITCHES)
5-17