Danfoss Series 40 M46 Service Manual

Overview
This section provides general steps to follow if undesirable system conditions occur. Follow these steps
until you solve the problem. Some of the items are system specific. For areas this manual covers, we
reference the section. Always observe the safety precautions in Introduction on page 5 and those related
to your specific equipment.
Safety precautions
C
Caution
High inlet vacuum causes cavitation which can damage internal pump components. Ensure charge pump
supply plumbing is adequate. Locating pump below the level of the reservoir, when possible, improves
inlet conditions.
C
Caution
Contamination can damage internal components and void the manufacturer’s warranty. Take
precautions to ensure system cleanliness when removing and reinstalling system lines
System noise or vibration
Item Description Action
Reservoir oil level Low oil level leads to cavitation. Fill reservoir.
Aeration of the oil/pump inlet vacuum Air in system decreases efficiency of units and
controls. Excessive noise, foaming oil, and heat may
indicate air in system.
Find location where air is entering into the
system and repair leak.
Check that inlet line is not restricted and is the
proper size.
Cold oil Cold oil may be too viscous for proper function:
pump cavitates.
Allow the oil to warm up to it’s normal operating
temperature with engine at idle speed.
Pump inlet vacuum High inlet vacuum causes noise/cavitation. Check that inlet line is not restricted and is the
proper size.
Check filter and bypass valve.
Shaft couplings A loose shaft coupling causes excessive noise. Replace loose shaft coupling. Replace pump
shaft.
Shaft alignment Misaligned shafts creates noise. Align shafts.
Charge/system relief valves Unusual noise may indicate sticking valves, possible
contamination.
Clean/replace valves and test pump. May be a
normal condition.
System operating hot
Item Description Action
Oil level in reservoir Insufficient hydraulic fluid will not meet the
cooling demands of system.
Fill the reservoir to the proper level with clean
hydraulic oil.
Heat exchanger (if equipped) The heat exchanger is not sufficiently cooling the
system.
Check the air flow and input air temperature for
the heat exchanger. Clean, repair, or replace the
heat exchanger as necessary.
Heat exchanger bypass valve A partially activated heat exchanger bypass valve
may result in heat generation within the system.
Verify that the bypass valve is fully closed and that
the valve is seating properly. Repair or replace as
necessary.
SCR (System Check / Relief) Valves A partially activated SCR valve or SCR valves with
relief settings too low may generate heat within
the system.
Verify that the SCR valve is seating properly and is
at the correct relief setting. Repair or replace it as
necessary.
Service Manual
Series 40 M46 Variable Pumps
Troubleshooting
14 |
©
Danfoss | September 2017 11026743 | AX00000027en-US0202

Danfoss Series 40 M46 Specifications

General

Brand	Danfoss
Model	Series 40 M46
Category	Water Pump
Language	English