TP-92116
Revised 8-98 16579/Meritor
Page 8
© Copyright Meritor WABCO, 1998 Printed in the USA
Installing the Pressure-Controlled
Check Valve (PCCV)
NOTE
The pressure-controlled check valve replaces the
one-way check valve on either the secondary or
primary service reservoir. Use pipe sealant or
teflon tape on all air fittings.
1. Identify the appropriate service reservoir (see
above) and locate the one-way check valve at
the inlet. This reservoir is fed by the supply
(wet) tank and typically supplies air to the front
brakes and air-operated accessories. For more
information about the PCCV, please refer to
TP-9672,
Air Dryer Application Guidelines
.
NOTE
If the one-way check valve is internal or otherwise
inaccessible, locate the check valve on the
primary reservoir.
2. Remove and
discard
the one-way check valve
from the reservoir.
NOTE
The arrow located on the face plate of the PCCV
must point
TOWARD
the reservoir. Figure 9
.
3. Install the pressure-controlled check valve in
place of the check valve you discarded. If space
is limited, you can use a 45˚ or 90˚ pipe fitting.
4. Reconnect the supply line from the supply
(wet) tank to the inlet of the PCCV. Reroute or
shorten the air hose as necessary.
Check the Vehicle’s Air System for
an Alcohol Evaporator
NOTE
Typically, an alcohol evaporator will be installed in
the line between the air dryer and the supply (wet)
tank. Common installations are on the truck’s
firewall, on a frame rail and behind the cab.
However, an alcohol evaporator can also be found
at other locations.
1. Check the vehicle’s air system to determine if
an alcohol evaporator is installed.
2. If an alcohol evaporator is installed in the air
system, check for a bypass line connected to
the evaporator, as illustrated in
Figure 10
.
CAUTION
If a check valve is installed in the bypass line, the
air dryer will not function properly. Damage to the
system can result.
3. If a bypass line is connected to the evaporator,
check to see if a check valve is installed in the
bypass line. If check valve is installed:
a. remove the check valve from the
bypass line,
b. remove the bypass line and
c. replace the bypass line with 1/4-inch
nylon line.
4. If there is no bypass line installed at the alcohol
evaporator, install one using 1/4-inch nylon
line.
Figure 10
.
Figure 9
M
E
R
I
T
O
R
W
A
C
O
P
/
N
4
3
4
1
0
0
3
1
0
0
Figure 10
BYPASS LINE
LINE TO
SUPPLY TANK
ALCOHOL
EVAPORATOR
1/4"
NYLON
LINE
LINE TO
AIR DRYER
