Page 100 - Webster Service Manual

95
The adjusting screws on the Pressuretrol, located in the
factory wired control panel, should be set carefully
according to instructions, below.
Setting Pump Pressure
1.
Set the differential scale indicator on the pressuretrol
at approximately 5 (half-way between 10 and bottom of
scale). This permanently sets the differential scale. Set
main scale indicator at 0, so supply pump can run con-
tinuously during purging of supply line.
2.
Purge lines. Run both supply pumps to assure both
are oil filled. For priming purposes, OSV valves can be
manually operated by inserting a stif f wire (paper clip)
through the cover hole, and depressing the diaphragm
plate.
3.
Pressure adjustment,
pump one:
Install compound
gauge in tee fitting in supply line of highest or most
remote burner. After starting
pump one
,
start all burn-
ers. With all burners operating at maximum firing rate,
adjust
pump one
so gauge at remote burners, reads 20 psi.
4
Pressuretrol adjustment: With all burners firing, switch
to
pump two
and adjust
pump two
so gauge at last
burner reads slight positive pressure (2-5 psi).
Gradually increase the pressuretrol main scale setting
until
pump two
stops,
pump one
starts, and alarm
buzzer sounds. Allow
pump one
to run and build pres-
sure. With
pump one
running and
pump two
off, turn
pump two pressure adjusting screw about one-quarter
turn clockwise.
5.
Pressure adjustment,
pump two:
Move selector
switch to
off
momentarily, then back to
pump two.
Alarm
will shut off and pump two will start. Adjust
pump two
pressure setting so it is the same as
pump one
(
set in
step three). Switch back and forth between both pumps
Differential
Scale
Adjusting
Screw
Main
Scale
Adjusting
Screw
Main
Scale
Indicator
Differential
Scale
Indicator
SPM Duplex Automatic Controls