T e c h n o l o g y , L L C
12
DAVCO Technology, LLC
www.davco.com
800-328-2611
1600 Woodland Drive, Saline, MI 48176-1629
DIESEL PRO
®
243
TECHNICAL MANUAL
F1215 REV H
DIESEL PRO
®
243 TECHNICAL MANUAL
DIAGNOSTIC PROCEDURES FOR PRE‑HEATER/OVERNIGHT HEATERS
Equipment Needed
•
A precision low resistance ohm meter capable of
measuring with accuracy to two decimal places .
•
Current flow meter (clamp‑on type for DC current) .
E
DO NOT USE a test light that has a wire probe for any
of these tests. If the wiring insulation is punctured,
moisture and road salt can penetrate into the wires
creating a corrosion issue and potential failure.
CAUTION!
E
Do not energize the pre‑heater outside of the
Diesel Pro. It can become very hot.
12VDC/24VDC PTC Pre‑heater Test Procedure
There are various configurations of pre‑heaters available,
including both 12VDC and 24VDC pre‑heaters .
The voltage and wattage ratings are stamped on the hex of
the pre‑heater for identification purposes .
1 . Disconnect the harness from the pre‑heater .
2 . Connect the ohm meter leads to the pins of the pre‑heat‑
er . Use the following to determine whether the pre‑heater
resistance value is in the acceptable range .
PTC Pre‑heater
Watts
Resistance Range (ohms)
12VDC
195W
0 .4 to 0 .6 @ 77°F (25°C)
24VDC
195W
2 .0 to 3 .0 @ 77°F (25°C)
12VDC
155W
0 .95 to 1 .2 @ 77°F (25°C)
120VAC Overnight Heater Test Procedure
1 . Disconnect the cord from the overnight heater .
2 . Connect the ohm meter leads to the pins of the overnight
heater . Use the following to determine whether the over‑
night heater resistance value is in the acceptable range .
Overnight Heater
Watts
Resistance Range (ohms)
120VAC
75W
173 to 203 @ 77°F (25°C)