FUEL PRO
®
485
TECHNICAL MANUAL
®
F1485 REV B
T e c h n o l o g y , L L C
11
DAVCO Technology, LLC
www.davco.com
800-328-2611
1600 Woodland Drive, Saline, MI 48176-1629
DIAGNOSTIC PROCEDURES - CHECK VALVE AND HEATER TESTING
Check Valve Diagnostics
1 . To test for proper check valve operation, remove the fuel
inlet hose and open the vent cap . Fuel should not flow
out of the Fuel Pro, although a slight seepage of fuel is
normal . If fuel drains back to the fuel tank, remove the
check valve assembly at the fuel inlet fitting .
2 . Open the vent cap . Open the drain valve by turning one to
one and a half revolutions . Drain the Fuel Pro completely .
Close the drain valve .
3 . Use a back-up wrench to hold the check valve body and
remove the fuel hose from the inlet of the Fuel Pro .
4 . Remove and disassemble the check valve assembly .
5 . Clean and inspect the check valve body . Replace the
check valve body if any cuts, grooves or nicks are evident
or if the ball seat is not smooth .
6 . Inspect the check valve spring and spring retainer . If the
spring or spring retainer is broken or if the check ball
has groves, nicks or is out of round, replace with a check
valve service kit . Otherwise, clean and reassemble the
check valve assembly . The spring retainer snaps into a
groove in the check-valve body .
7 . Replace the check valve assembly into the body and
torque to 30-55 ft-lb .
8 . Connect the fuel inlet hose, using liquid or paste type
thread sealant .
9 . Prime the fuel system, start the engine and check for any
fuel leaks .
PTC Pre-heater/Overnight Heater
Testing Procedures
E
Do not energize pre-heater/heater outside of the
Diesel Pro. Caution! Very hot.
Equipment Needed: A precision low resistance ohm
meter capable of measuring with accuracy to two decimal
places.
1 . Disconnect the harness from the pre-heater or overnight
heater .
2 . Connect the ohm meter leads to the pins of the pre-
heater or overnight heater . Use the following to determine
whether the resistance value is in the acceptable range .
PTC Pre-heater
Watts Resistance Range (ohms)
12VDC (PTC)
195 W 0 .4 to 0 .6 @ 77°F (25°C)
24VDC (PTC)
195 W 2 .0-3 .0 @ 77°F (25°C)
12VDC (PTC)
155W
0 .95 to 1 .2 @ 77°F (25°C)
Overnight Heater
Watts Resistance Range (ohms)
120VAC
75 W
173 to 203 @ 77°F (25°C)