Customer Service - Danfoss MCV105C Manual

TROUBLESHOOTING FAILURE MODES (continued)
C. THE PUMP RETURNS SLOWLY OR NOT AT ALL TO
NEUTRAL
1. Check charge pump pressure. If sufficient:
2. Unbolt the second stage from the pump and check
the spool and sleeve for contamination or damage.
If cleaning these parts clears up the problem there
is a filtration problem. Check the charge pump filter
and change pump oil.
D. PUMP OPERATES IN ONE DIRECTION
1. Check the electrical signal from the command
source. Current should flow in both directions. If
not, there is an electrical problem.
2. Jog the manual operator on top of the pilot. This
may free a contaminant in the pilot itself. If after
several jogs to either side the pump continues to
operate in only one direction, replace the pilot.

CUSTOMER SERVICE

IN NORTH AMERICA ORDER FACTORY INSTALLED
EDC ON PUMP FROM
Danfoss (US) Company
2800 East 13th Street
Ames, Iowa 50010
Telephone: (515) 239-6000
Fax: (515) 239-6318
IN NORTH AMERICA ORDER INDIVIDUAL EDCs FROM
Danfoss (US) Company
Customer Service Department
3500 Annapolis Lane North
Minneapolis, Minnesota 55447
Phone: (763) 509-2084
Fax: (763) 559-0108
DEVICE REPAIR
For devices in need of repair or evaluation, include a
description of the problem and what work you believe
needs to be done, along with your name, address and
telephone number.
RETURN TO
Danfoss (US) Company
Return Goods Department
3500 Annapolis Lane North
Minneapolis, Minnesota 55447
© Danfoss, 2014-05
E. PUMP DOES NOT REACH FULL OUTPUT
1. Check the input current to the pilot. Verify that full
drive current from the command source is at least as
high as that specified. See Data, Electrical, page 2.
2. If the current drive is high enough, jog the manual
operator on the pilot. If full output is attained,
replace the pilot. If pump output is low on both sides
of null, the filter may be plugged in the second stage.
If the pump output is full on one side and low on the
other, replace the pilot.
F. PUMP NULL DEADBAND IS ASYMMETRICAL
1. Adjust the second stage null using the null adjust
procedure described previously.
2. If the problem persists and the noise from the pump
on either side of null indicates that null is unstable
(i.e., the pump creeps), replace the pilot.
See Customer Service, below, for repairs and re-
turns.
IN EUROPE ORDER FROM
Danfoss (Neumünster) GmbH & Co.
Order Entry Department
Krokamp 35
Postfach 2460
D-24531 Neumünster
Germany
Phone: 49-4321-8710
Fax: 49-4321-871355
11152452 • Rev AA • May 2014
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