PS Magazine - TB 43-PS-721
PS, The Preventative Maintenance Monthly
ISSUE 721
DECEMBER 2012
21
PS 721
DEC 12
Dear Editor,
Recently, I was running some tests on several large capacity field heaters
(LCFH), Type II. One of the heaters failed and fault code H562 appeared on
the LED display of the operator control panel. Fault code H562 indicates
a short circuit at the diesel engine fuel solenoid relay driver on the main
control box printed circuit board.
WP 0012-12 of TM 10-4520-265-14&P (Jun 09) calls for the
following action if you get fault code H562:
1
Turn the power switch to OFF and disconnect the negative battery
terminal.
2
Replace main control box assembly like it says in WP 0074 of the TM.
After some troubleshooting with a multimeter, I found the real problem: A
shorted engine shutdown solenoid triggered fault code H562. The solenoid
reading was .004 ohms. It should have been around .075 to .078 ohms.
So, before you replace the main control box, check the resistance at the
engine shutdown solenoid. If you get a low reading, it’s the solenoid that
needs replacing, not the main control box.
The solenoid, NSN 4810-01-568-7755, is Item 185 in Fig 8 (Sheet 10
of 10) of the TM.
SSG Rafael Rosario
CSMS
110th Maint Co
Devens, MA
Editor’s note:
Great work, Sergeant. You saved a bundle by replacing the engine
shutdown solenoid. It costs a small fraction of what the main control box costs.
The TM is in line for an update. Until then, make a note to change the corrective
action on WP 0012-12, Table 1. LCFH Type II Fault Code Troubleshooting
Procedures. If you get fault code H562, troubleshoot the engine shutdown
solenoid before you do anything else.
NSN 8415-
Size
Small
Medium
Large
X-large
XX-large
01-534-7375
01-534-7376
01-534-7377
01-534-7383
01-534-7387
Large Capacity Field
Heater, Type II…
Clothing…
What the Well-Dressed Mechanic Wears
Planning to do a
little mechanical
work?
Feel the
need to
“blend in”?
Then it
might pay
you to
stock up on
universal
camouflage
mechanic’s
coveralls.
Here
are the
available
sizes…
The coveralls are made of
cotton/nylon twill and have a
front, slide fastener.
You’ll find them at the
DoD Emall website:
https://dod-emall.dla.mil/acct/
To find other kinds of
coveralls on the website, do a
quick search for coveralls.
…may
not
be in our main
control boxes,
But in our
soLenOids!
The Fault,
Dear
Brutus.
..
If you get fault code H562…
…troubleshoot engine shutdown solenoid
721 20-21.indd
1-2
11/6/12
11:21 AM
Click here for a copy of these articles to save or email.
Back to TopBack to Top
