19
If the four-way does not shift, the same bed will continue to
pressurize, and the pressure relief valve will relieve the pressure.
There are several reasons for the four-way to malfunction.The
cause of failure must be determined before corrective action
can be taken.
Some reasons for four-way failure are:
Continuous or no voltage to four-way.
Foreign matter inside valve preventing spool from shifting.
To test the four-way valve (Figure 6):
1. Remove the front cabinet.
2. Connect the pressure-vacuum gauges furnished in the service
kit to the test points at the top of the sieve beds in order to
observe unit cycling and bed pressures. Refer to the section
on “Normal Operating Sequence.”
3. If it is determined that the four-way did not shift, continue
testing with step 4.
4. Testing for proper four-way voltage is done at the four-way
connector on the PC board. Place the test leads of a volt-
meter in the two outside pins of the connector to check volt-
age to one of the solenoids. Place the voltmeter leads on the
two inside pins to check voltage to the other solenoid.
Approximately 7.5 VDC (
12-15 VDC on non-OSD and early-
OSD models) should be present for 9-
10 seconds alternately
on each solenoid (the green 4-way light on the PC board will
be illuminated). Energizing the right solenoid will cause the left
bed to pressurize, while energizing the left solenoid causes the
right bed to pressurize.
5. If this reading is not obtained, check for loose or broken wires
from the four-way valve to the PC board. If no loose or bro-
ken wires are found, replace the PC board.
6. If approximately 7.5 VDC (
12-15 VDC on non-OSD and early-
OSD models) is measured at the connecting leads to the
valve, then the valve is either defective or foreign matter has
gotten inside the valve causing it to malfunction. In either case
the four-way valve must be removed to clean or replace it.
To remove the four-way valve: (Figures 6 & 7)
1. Unplug the unit from the wall outlet.
2. Remove the front cabinet and loosen the bib.
3. Disconnect the four-way connector from the PC board.
4. Loosen clamps and remove sieve bed hoses from bottom of
four-way.
5. Remove the three screws that secure valve to the front of unit.
6. Loosen clamp and remove the compressor hose and exhaust
hose(s) from four-way.Valve may now be cleaned or replaced.
To replace the four-way valve:
1. Reverse the above removal procedure.
2. If the tubing needs to be replaced make sure the new tubing is
identical to the old tubing and is exactly the same length in
order to ensure proper silencing.
To clean the four-way valve: (Figure 13)
1. Remove the valve as described above.
2. Using a flat screwdriver loosen the two slotted screws on
both ends of the four-way.The solenoids may now be separat-
ed from the valve body.
3. Remove the spring retainer, spring, and spacer from each end
of the valve body. Note the position of these parts.
4. Carefully remove the spool from the valve body.
NOTE: The spool and sleeve are a matched set.Take care not
to mix different valve parts.
5. Using a non-metallic rod or dowel with a diameter no greater
than the sleeve, slowly push the sleeve out either end of the
valve body.
NOTE: Pushing too fast will cause o-rings to roll and jam.
6. Inspect the o-rings on sleeve. If they are badly worn or defec-
tive, they should be replaced using the valve rebuild kit (part#
5
15DZ-707).
7. The spool and sleeve can be cleaned using a spray-on evapora-
tive electro-contact cleaner; for example, ENVI•RO•TECH™
1677 or cleaned with a detergent powder; for example,
ALCONOX
®
. If using these cleaners, follow manufacturer's
instructions carefully. DO NOT USE ANY TYPE OF
CLEANSER THAT IS ABRASIVE OR LEAVES A RESIDUE.
8. Rinse the spool and sleeve thoroughly and dry with a soft,
clean, lint-free cloth.
9. Ensure that the air passages (ports) in the valve body are free
of any foreign matter.A clean, lint-free cloth or a compressed
air hose can be used to clean these.
10. Carefully push sleeve into valve body (turning it slightly) so
you do not cut or nick the o-rings. Be sure sleeve is posi-
tioned properly in valve body.
11.Reassemble remaining parts of valve in reverse order.
12. Replace valve as described above.
HOUR METER
To replace the hour meter (Figure 9):
1. Make sure the unit is unplugged from the wall outlet.
2. Remove the front and back cabinets and loosen the bib.
3. Disconnect the hour meter connector from the PC board.
4. Remove the two screws securing the hour meter and remove
the meter.
5. Install a new hour meter and secure with the two screws.
6. Connect the hour meter to the PC board.
ALCONOX® is a registered trademark of Alconox, Inc.
ENVI•RO•TECH™ is a trademark of Tech Spray, Inc.
COMPONENT TESTING, REPAIR, AND REPLACEMENT
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