Van Air Systems FR-1200 - Manual (Page 14)

PAGE 14
10.4 CHECKING THE INLET TRANSFER VALVE
The inlet transfer valve should not change position until both towers
are at equal pressure. At tower changeover, the regenerating tower
should approach full line pressure before the inlet valve will switch.
Make sure that there are no leaks in the piping or fittings. Make
sure that the purge exhaust valves are closing and that the purge
metering valve is properly set.
The exhaust ports on top of the pilot valves (SV1 & SV2) should not
have air exhausting through them continuously. If air is exhausting
continuously through either of the exhaust ports, the inlet transfer
valve or exhaust valves are faulty and should be rebuilt or replaced.
To test the inlet transfer valve for proper operation, turn off the
power, isolate and depressurize the dryer.
Remove the two pilot lines to the inlet valve. The pilot lines are
connected to the outside flanges of the valve. Reference FIGURE
10C. Using an air nozzle and clean air, pressurize one of the ports.
Observe the position indicator. It should move in the direction of
the port that is being pressurized. No air should be exhausting from
the other port. Pressurize the other port. The valve should move to
the other side. If the valve does not move or air is being exhausted
out of the port that is not pressurized, the inlet transfer valve must
be rebuilt or replaced. Reference SECTION 11.3 for repair kit part
numbers.
10.5 CHECKING THE PURGE EXHAUST VALVES
The purge exhaust valves are normally closed. They can be
checked by removing the pilot air lines to them. The valves should
be closed.
Using an air nozzle and clean air, pressurize the purge exhaust
valves. The valves should open when pressurized. If valve does
not open and close, it should be rebuilt or replaced. See SECTION
11.3 for repair kit part number.
10.6 CHECKING THE OUTLET CHECK VALVES
This dryer system uses two check valves for outlet air control. If
either of the outlet valves fails, one of the following will occur:
• A large amount of air will purge from one tower
• The outlet air flow will be blocked
If either happens, the faulty check valve must be replaced. See
SECTION 11.3 for part number.
TROUBLESHOOTING SECTION 10
FIGURE 10C INLET TRANSFER VALVE DETAIL