Leslie Controls Pilot Controller - Manual (Page 12)

Page 12
2. Then turn lever screw (26) downward (out of lever) 3/4
turn for all low pressure pilots (up to and including the
50-125 psig range; 1-1/4 turns for high pressure
ranges (100-200 psig and over). Tighten locknut (27).
3. Reconnect output to D.C.V.
NOTE: Differential and Ratio pilot controller (UDDV, UDRV or
UDDD types) may require slight stem length readjustment to
obtain complete balancing of the sensing diaphragm, if
changes in static pressure on the diaphragm cause changes
in pilot controller setpoint. To check this supply 20 psig oper-
ating pressure to pilot. Adjust pilot for a constant differential
within its range. Apply a change in static pressure across the
upper sensing diaphragms and observe output pressure on
right hand gauge. If output pressure changes, readjust stem
length in small increments (by turning adjusting pin or lever
screw upward or downward as required) until changes in sta-
tic pressure do not affect the air output pressure).
To Decrease Sensitivity of Pilot Controllers
(Constant Pressure Types Only)
1. Readjust nozzle stop to non-leak off position (if leak off
is in use).
2. Move diaphragm slightly away from its mean position
by readjusting stem length in small increments of about
1/8 of a turn until desired operation is obtained.
Caution: DO NOT turn excessively.
PDA-1, PRW-1 PDQ Pilot Controllers — In reducing
service move diaphragm upward by increasing the stem
length. In back pressure or relief service, move
diaphragm downward by decreasing the stem length.
PRA-1, PRW-1, PRQ Pilot Controllers — In reducing
service move diaphragm downward by decreasing stem
length. In back pressure or relief service, move
diaphragm upward by increasing the stem length.
After making readjustment retest pilot controller to
make sure that it will change the operating output pres-
sure from 0 psig to 20 psig or vice versa with a reason-
able change in controller pressure.
Figure 16. — Back Pressure or Pressure Relief Service
For Differential Pilot Installation Sketches,
See Instructions 20/2.5.3
For Ratio Pilot Installation Sketch,
See Instructions 20/3.5.1
Operating
Medium
Pilot
Controller
Control
Valve