CHAPTERS
CAUTION!
To
prevent
burner
shutdown
at
other
tf:"lan
low
fire
setting,
ad-
just
the
modulating
pressure
control
to
modulate
to
low
fire
BEFORE
the
operating
limit
pressure
control
shuts
off
the
burner. Failure
to
heed
this
cau-
tion
could
result
In damage
to
the
equipment.
·
G.
OPERATING
LIMIT
PRESSURE
CONTROL
(Steam)
Set "cut-out" (burner-off) pressure
on
the main
scale using the large adjusting screw. Set dif-
ferential
on
the short scale turning the small
adjusting
screw
until the indicator points to the
desired difference between cut-out and cut-in
pressures.
The
"cut-in" (burner-on) pressure is
the cut-out pressure
MINUS
the differential. The
cut-out pressure should not exceed
90%
of
the
safety valve setting.
H.
HIGH
LIMIT
PRESSURE
CONTROL
(Steam)
Set "cut-out" (burner off) pressure
on
the scale
using the adjusting screw.
The
control will break
a circuit when pressure reaches this point.
The
setting should
be
sufficiently above the operating
limit pressure control to avoid shutdowns, and
preferably not exceed
90%
of
the safety valve
setting. This control requires manual resetting
after tripping
on
a pressure increase.
To
reset,
allow pressure to return
to normal and then press
the reset button.
. CHAPTER
s..a
ADJUSTMENT PROCEDURES
L
MODULATING
TEMPERATURE
CONTROL
(Hot
Water)
Tum
the knob
on
front
of
the case until the
pointer indicates the desired setpoint tempera-
ture.
This
is the center point
of
a proportional
ia.nge.
The
control has a 3
..
3o• differential and
may
be adjusted
to
vary the temperature range ·
within which modulation is desired. With the
cover off,
tum
the adjustment wheel until the
pointer indicates the desired range.
CAUTION!
To
prevent
burner
shutdown
at
other
than
low
fire
setting,
ad-
just
the
modulating
tempera-
ture
control
to
modulate
to
low
fire BEFORE
the
operating
limit
temperature
control
shuts
off
the burner.
Failure
to
heed
this
caution
could
result
In damage
to
the
equipment.
J.
OPERATING
LIMIT
TEMPERATURE
CONTROL
(Hot
Water)
Set the "cut-out" (burner off) temperature on the
scale by inserting a screwdriver through the
cover opening
to
engage the slotted head adjust-
ing screw.
The
"cut-in" (burner on) temperature
is
the cut-
out temperature MINUS the differential. The
differential is adjusted from
So
to 30° F.
750-150
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