T e c h n o l o g y , L L C
DIESEL PRO
®
245
TECHNICAL MANUAL FOR DTNA
10
www.davco.com
800-328-2611
Saline, MI 48176
P. O. Box 487
DAVCO Technology, LLC
DIAGNOSTIC PROCEDURES - CHECK VALVE AND HEATER TESTING
F1353 REV B
Check Valve Service
To test for proper check valve operation, remove the fuel inlet
hose and open the vent cap. Fuel should not flow out of the
Diesel 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. Refer to the table on the Service Parts
page for ordering information.
1. Use a back-up wrench to hold the check valve body and
remove the fuel hose from the inlet of the Diesel Pro.
2. Remove and disassemble the check valve assembly.
3. 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.
4. 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.
5. The spring retainer snaps into a groove in the check-valve
body.
6. Replace the check valve assembly into the body and
torque to 25-40 ft-lbs.
7. Connect the fuel inlet hose, using liquid or paste type
thread sealant.
8. Prime the fuel system, start the engine and check for any
fuel leaks.
PTC Pre-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. Connect the
ohm meter leads to the pins of the pre-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)
