Danfoss H1T 045 User Manual

Item Description Action
Exchange system pressure
limiters
Exchanging the pressure limiter valves will show if the
problem is related to the valve function.
If the problem changes direction, replace the valve that
does not operate correctly.
Exchange high pressure
relief valves
Exchanging the high pressure relief valves will show if the
problem is related to the valve function.
If the problem changes direction, replace the valve that
does not operate correctly.
Servo pressure low or
decaying
Damaged servo seals may prevent servo piston from
stroking the pump.
Check for torn/missing servo seals. Replace and retest. Only
a Danfoss Authorized Service Center may remove the servo
piston without voiding the warranty.
Bypass function open Open bypass will cause one or both directions to be
inoperative.
Close bypass function.
System Operating Hot
Item Description Action
Oil level in reservoir
Insufficient hydraulic fluid will not meet cooling demands
of system.
Fill reservoir to proper level.
Heat exchanger
Heat exchanger is not sufficiently cooling the system.
•
Check air flow and input air temperature for heat
exchanger
•
Clean, repair or replace heat exchanger
Charge pressure Low charge pressure will overwork system.
•
Measure charge pressure.
•
Inspect and adjust or replace charge relief valve.
•
Inspect charge pump; repair or replace charge pump.
Charge pump inlet vacuum
High inlet vacuum will overwork system.
A dirty filter will increase the inlet vacuum. Inadequate line
size will restrict flow.
•
Check charge inlet vacuum. If high, inspect inlet filter
and replace as necessary
•
Check for adequate line size, length or other restrictions
System relief pressure
settings
If the system relief valves are worn, contaminated, or valve
settings are too low, the relief valves will be overworked.
Verify settings of pressure limiters and high pressure relief
valves and adjust or replace valves as necessary.
System pressure
Frequent or long term operation over system relief setting
will create heat in system.
Measure system pressure. If pressure is too high, reduce
loads.
System Will Not Operate in Either Direction
Item Description Action
Oil level in reservoir. Insufficient hydraulic fluid to supply system loop. Fill reservoir to proper level.
Pump control orifices Control orifices are blocked. Clean control orifices.
Pump control screens Control screens are blocked. Replace control screens. Only a Danfoss Authorized Service
Center may remove the unit’s endcap without voiding the
warranty.
Bypass function open If bypass function is open, the system loop will be
depressurized.
Close bypass valves. Replace high pressure relief valve if
defective.
Low charge pressure with
pump in neutral
Low charge pressure insufficient to recharge system loop. Measure charge pressure with the pump in neutral. If
pressure is low, go to Pump charge relief valve.
Low charge pressure with
pump in stroke
Low charge pressure resulting from elevated loop leakage.
Insufficient control pressure to hold pump in stroke.
Deadhead the pump to isolate it from the motor.With
pump in partial stroke and engaged for only a few seconds,
check pump charge pressure. Low charge pressure
indicates a malfunctioning pump. Continue to next step.
Good charge pressure indicates a malfunctioning motor or
other system component. Check motor charge relief
operation (if present).
Pump charge relief valve A pump charge relief valve that is leaky, contaminated, or
set too low will depressurize the system.
Adjust or replace pump charge relief valve as necessary.
Charge pump inlet filter A clogged filter will under supply system loop. Inspect filter and replace if necessary.
Service Manual
H1T 045/053, 060/068 Axial Piston Tandem Pumps
Troubleshooting
©
Danfoss | September 2020 AX152886481761en-000405 | 37

Danfoss H1T 045 Specifications

General

Brand	Danfoss
Model	H1T 045
Category	Water Pump
Language	English