4.  Remove the locknut and washer from the shaft. A screw driver slot is provided at the end of the 
shaft to prevent it from rotating while removing this nut. 
 
5.  The diaphragm plates and diaphragm can now be removed. Make note of the curvature of the 
diaphragm plates. 
 
6.  Remove the O-ring retainer. This may require a special tool or a deep well socket, depending on 
valve size. You can now remove the disk, holder and shaft. 
 
7.  Remove the brass seat. A special tool may be required. 
 
8.  Reassembly is reverse of disassembly. Replace ALL the O-rings, seat and diaphragm as you go. 
A very light application of an anti-seize product on threads of the brass seat and O-ring retainer 
will make future repairs easier. Do not neglect the shaft O-rings which are internal to the O-ring 
retainer. 
 
Section 10 Parts (General Parts Description) 
 
A.  DESICCANT - An adsorbent used for drying air or gases. Proper quantity, size and type are 
necessary. 
 
B.  INLET SWITCHING VALVES - Normally Open Air Operated Diaphragm Valves used to direct the air 
flow through the towers. 
 
C. EXHAUST VALVES - Normally Closed Air Operated Diaphragm valves used to exhaust purge air, hold 
air in tower on line, and exhaust air from tower ready to be regenerated. 
 
D.  OUTLET AND PURGE CHECK VALVES - Valves that allow full flow in one direction and no flow in the 
other are used in conjunction with the inlet and exhaust valve to accomplish desired flow of process and 
purge air. 
 
E.  SAFETY RELIEF VALVES - Furnished on each tower to protect the vessels from overpressure 
situations. Standard setting is 150 PSIG. 
 
F.  PURGE EXHAUST MUFFLER - Furnished to reduce exhaust noise during purge and blow down for 
personnel protection and to comply with OSHA standards. Mufflers offer no benefit to the operation of 
the dryer and are a maintenance concern. Consideration should be given to locating the exhaust in an 
area where mufflers would not be required. 
 
G. PURGE CONTROL REGULATOR OR VALVE- Furnished to adjust and regulate   purge flow 
for generation. 
 
H.   SOLID STATE CONTROLLER/SEQUENCE ANNUN- CIATOR PANEL - Furnished for cycle control. 
Outputs operate 5 electric solenoid valves. Provides for Variable Cycle Control. Provides interface with 
optional Powerloc and has integral lights to provide visual cycle indication. Has built-in automatic drain 
control. All hard wired connections, including field power connection, are made to this board. 
 
I.  TOWER PRESSURE GAUGES - Furnished to read pressure in each tower. On-line tower should 
read line pressure, regenerating tower should read “0” PSIG. 
 
J.  PURGE FLOW INDICATOR (center gauge) - Furnished to indicate and monitor proper purge 
flow. 
 
K.  CONTROL SOLENOIDS - (4) 3-way normally closed electric solenoid valves, operated by the solid 
state controller, that in turn provide a control air signal to operate the inlet and exhaust valves. 
 
L.  REPRESSURIZATION SOLENOID (Variable Cycle Control Bypass) - A 2-way normally closed 
electric solenoid valve provided to insure tower repressurization before switching, even at low flows. 
 
M.   CONTROL AIR FILTERS - Filters control air, which is taken from the dryer outlet, to protect the control 
solenoids from desiccant dust. Also protects Powerloc Probe where applicable.