MAINTENANCE
PH/EH SERIES HEATLESS AIR DRYER
MAINTENANCE
WARNING
Disconnect power and depressurize the dryer
completely before starting maintenance procedures.
General
During the first month, clean or replace the pilot air filter
element and repeat periodically. Also, clean the exhaust
mufflers. Replace mufflers if the tower pressure gauge
reads any back pressure during the regeneration cycle.
No lubrication is required for any system.
Daily
Check auto drain on prefilter every shift.
Weekly
1. Check the dryer’s sequence of operation, and valve
operation.
2. Check the purge control setting.
3. Check the operating conditions; inlet pressure, inlet
temperature and the flow rate.
4. Check the moisture indicator. ORANGE color
indicates DRY conditions. If the color is
TRANSLUCENT, refer to the moisture indicator
chart on alarm conditions for probable cause.
(Optional equipment.)
5. Check the purge mufflers for blockage. Possible
indication is back pressure on tower under
regeneration. Replace if necessary.
6. Check the pressure drop across prefilter and
afterfilter. Replace the elements when the differential
reaches 5-10 PSID.
Monthly
Check the pilot air filter element. Replace if necessary.
Three Months
1. Every three (3) months, close the purge adjusting
valve momentarily to check for any leaks in the inlet
and/or check valves indicated by air coming through
the exhaust mufflers.
2. Check the prefilter and afterfilter elements for
excessive clogging or possible damage. Replace as
necessary.
3. Blow down relief valves.
4. Check outlet dewpoint conditions.
Twelve Months
1. Close the inlet and outlet valves on the dryer or
bypass the dryer and completely depressurize the
dryer system. Open the desiccant fill port and check
visually. If desiccant is contaminated with oil or
broken, replace the desiccant.
2. Check for leaking check valves per Table 1
symptoms C & D in Troubleshooting Guide. Repair
or replace as necessary.
3. Remove the inlet switching valves and purge
exhaust valves. Clean and replace worn out seats
and seals.
4. Inspect the pilot air cylinders for leaks or worn out
seals. Repair or replace as necessary.
5. Check repressurizing valve. Repair or replace as
necessary.
6. Check pilot air solenoid valves for possible defects.
Dewpoint Sensor (Optional)
It is recommended to recalibrate the sensor probe
annually to maintain accuracy. Contact your local
distributor or factory for exchange policy.
Calibration:
To maintain accuracy, replace the probe
every two years.
Probe Replacement:
Turn the normal/demand selector
switch to the normal position. This will disable the
contacts for Dewpoint Demand. Isolate and depressurize
the probe chamber. Remove, and replace the probe.
Pressurize the probe chamber and connect the sensor
cable. A small amount of sample air (approximately 2-10
SCFH) should expel out the chamber needle valve.
Mufflers
Purge mufflers are installed to reduce the noise level.
The mufflers tend to plug up and increase back pressure
over time due to oil carryover and contaminants from
compressor, or due to desiccant dust at the initial start-
up. To eliminate back pressure, replace muffler after
three months, or when the back pressure increases in
the regenerating tower.
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