Leslie Controls Pilot Controller - Manual (Page 10)

Page 10
SECTION III — MAINTENANCE
(CONSULT FIGURES OF APPLICABLE DRAWINGS)
IMPORTANT: ALWAYS MAKE SURE THAT CONTROL PIPES
AND AIR SUPPLY LINES ARE FREE AND CLEAR OF FOR-
EIGN MATTER.
Dismantling Pilot Valve Bodies
1. By-pass diaphragm control valve if system operation is
necessary maintenance. Close air supply and control
pipe stop valves to pilot controller. Remove cover screw
and cover from base.
2. In lever action types (PRA-1, etc.), lift right hand end of
lever and remove lever pin assembly. (DO NOT disturb
setting of these parts as they are designed for initial
factory length adjustment only).
Loosen bottom plug (47.) Remove body screws (36)
and take body assembly off base (25). Disassemble
diaphragm plate capscrews (31), diaphragm plate (30)
and nozzle disc diaphragm assembly (29) from body.
3. Take out flange ring screws (34), flange ring complete
(37) and nozzle (42) with assembled parts. Disassemble
nozzle stop (32) from flange ring. Remove bottom plug
(47), pilot valve spring (45) and seat (43) from body
unless it is damaged and must be replaced. (If removal
is necessary, use piece of flat stock or wide screwdriver
in lugs to loosen and unscrew).
Cleaning — Replacing Parts
1. Wipe all parts clean including pilot valve seat. Use an
approved, non-residue forming solvent, if necessary.
2. Inspect all parts. Replace any worn or damaged parts
including neoprene nozzle diaphragm (40) and “O” ring
body gaskets (35) in back of body.
3. To change nozzle diaphragm insert pin in bottom port in
nozzle for grip, loosen diaphragm nut (39). Disassemble
parts. Replace diaphragm. Reassemble parts. Tighten
diaphragm nut.
NOTE: Do not use abrasive cloth on parts or grind in pilot
valve as parts may be damaged or important dimensions
changed. If necessary, crocus cloth may be used. All working
parts must be clean and free moving. Open air supply line
valve and blow out ports.
Reassembling Pilot Valve Bodies
1. Place pilot valve spring (45) and pilot valve (44) (with
seating face upward) on bottom plug. Position parts in
body. Screw bottom plug all the way in. Tighten.
2. Insert nozzle (42) with assembled parts in upper end of
body. Screw nozzle stop (32) part way into flange ring
(37). Position flange ring complete on nozzle diaphragm
(nozzle stop upward) with blade spring (33) on left hand
side facing gauges. Insert flange ring screws (34)
through flange ring and into body threads. Start careful-
ly into threads. Tighten evenly and sufficiently to make
a good air seal.
3. Replace body assembly on base (25). Insert body
screws (36) through body and into base threads. Start
carefully into threads. Tighten securely to make a good
gasket seal between body and base.
4. Note: Adjust nozzle stop setting for leak off or non-leak
off setting at this point. Proceed as described for the
particular setting desired.
Adjusting Response Sensitivity
To adjust response sensitivity of a pilot controller supply 20-
22 psig air to pilot controller then proceed as follows:
For Normal Response Sensitivity: Adjust pilot controller for
very minor or no leak off. To do this, relieve pressure of blade
spring on nozzle stop by pressing lightly downward o it with
finger. Then screw nozzle stop downward until it is felt to
barely seat on nozzle nut (39).
For Supersensitive Response: Adjust pilot controller for con-
tinuous leak off. To do this slowly screw nozzle stop further
downward until operating pressure flow is just detectable
through nozzle bleed port. To check amount of leak off, place
finger lightly over nozzle bleed port to seal air (do not press
down on nozzle). Air pressure in output line to diaphragm
control valve should not build up any faster than 3-5 psig in
20-30 seconds. Lock nozzle stop with blade spring.
To Test Pilot Controller Body and Diaphragm Control Valve:
For response press downward on center of nozzle until 20-22
psig air pressure registers on output gauge. Control valve
should move through full travel. Release nozzle. Air output
pressure should drop to 0 psig and control valve should return
to its original position.
NOTE: Maintenance work can be performed on superstruc-
ture, if necessary, as described under “Replacing Upper
Diaphragm.” If unnecessary, proceed with Reassembly Step 5.
5. Place nozzle disc assembly in body recess with disc
toward nozzle.
In PDA-1, etc. types, remove screw (27) from stem
complete (13). Lift extension pin (86) upward into stem
complete then replace diaphragm cover on body. Insert
capscrews (31) through cover into body. Tighten.
Position end of adjusting pin (53) properly in recess in
nozzle disc then insert screw (27) through stem com-
plete and extension pin and tighten.
In PRA-1, etc. types, replace cover (30) on body. Insert
capscrews (29). Tighten. Then lift right hand end of
lever and insert lever pin assembly in place between
lever and nozzle disc making sure that pointed ends
center in recesses in disc and lever. Check opposite
end of lever to make sure that point of stem complete
(13) has centered in recess in set-screw properly.
NOTE: If it was found necessary to disturb adjustment of
lever screw of adjusting pin readjust as described under
“STEM LENGTH ADJUSTMENT” shown on Page 4.