Maintenance – Harken HYDRO 2 Power Unit User Manual
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Hydro 2
Maintenance
CAUTION! If necessary, top off oil reservoir using proper fluid type. Do not mix oil types. Refer to Oil Equivalent Table,
pg. 15. Only use filter elements capable of meeting or exceeding the oil cleanliness level requirements.
IMPORTANT! Oil filter status indicator functions only when unit is powered and when motor and pump are running. In operating
conditions with high levels of airborne particles, inspect breather at frequent intervals.
IMPORTANT! Conduct recommended oil change schedule in accordance with fluid type, aging and oil contamination level. Oil
condition depends on moisture content and additive level. In operating conditions with high levels of airborne particles and/or
elevated thermal loads, reduce intervals between oil changes accordingly.
Hydraulic Oil Change Schedule
•	 After	first	500	operating	hours 
•	 Every	1000	operating	hours	or	biannually	regardless	of	accumulated	operating	hours 
•	 Oil	change	interval	lengths	can	be	adjusted	(longer	or	shorter)	if	results	of	laboratory	fluid	sampling	and	oil	analysis	reveal	oil	is	 
 cleaner or more contaminated than expected at 1000 operating hours.
How to Change Oil
Oil change intervals are recommended based on various factors such as the type of fluid, the degree of aging, and the contamination of 
the oil. Water content and the levels of additives are also significant factors in determining the condition of the oil. Important guidelines 
to remember are:
•	 Follow	proper	procedures	when	changing	oil.	Improper	cleaning	procedures	may	contaminate	hydraulic	system. 
•	 Perform	oil	changes	in	a	warm	operating	environment.	 
•	 Drain	old	oil	before	adding	new.	Reservoir	may	be	emptied	via	one	of	two	methods: 
 
1. Place basin near HPU beneath drain plug. Remove plug and let oil drain into basin until reservoir is empty.
2. Use siphon/oil pump method to pull oil up through hose in filler tube. Use a basin to collect oil.
•	 Once	oil	is	drained,	use	lint-free	rags	to	clean	reservoir.	Remove	debris	prior	to	refilling.	 
•	 Filter	oil	prior	to	filling	reservoir.	Never	fill	a	reservoir	through	a	filler	breather	without	filtering	it	prior	to	or	during	the	filling	process. 
•	 Take	care	to	not	introduce	contaminates	from	the	filter	housing	when	removing	filter.
Note: Always dispose of oil properly. Contact your local waste authority, and follow guidelines for recycling and/or disposal. 
CAUTION! Filter oil prior to filling the reservoir. Cleanliness of oil directly from barrel is not sufficient for system operation.
Contact local hydraulic service company for filter carts or pre-filtered oil.
Problems occurring during oil change result from:
•	 Use	of	unsuitable	hydraulic	oil 
•	 Use	of	oil	which	was	contaminated	due	to	faulty	storage 
•	 Failure	to	clean	reservoir 
•	 Inadequate	cleanliness	when	filling,	i.e.	dirty	drums	or	containers 
•	 Filling	to	improper	levels
Harken Hydraulic Power Units will provide years trouble free operation with proper, routine 
maintenance. Adherence to a maintenance schedule will lengthen component life, reduce downtime, 
and minimize repair costs. Typical maintenance includes regular oil changes, replacing filter elements, 
oil sampling and component inspection. Under normal operating conditions, the following maintenance 
schedules are suggested:
Filter Element Replacement Schedule
•	 Within	eight	(8)	operating	hours	after	the	initial	commissioning 
•	 Every	500	operating	hours	or	when	Oil	Filter	Status	Indicator	signals	a	dirty	filter 
•	 During	any	complete	oil	change
Filter supplied with the unit is a drop-in element (HYFEH-10). Ensure O-rings are fitted into ends of filter 
prior to installation. Contact Harken for replacement elements. If using other manufacturer, cross- 
reference the filter and use element rated for 10 micron or better.
Oil Filter Status Indicator
