Here are the official Kranzle Manual Recommendations and the Official Kranzle USA position
The first oil change should be carried out after approximately 50 operating hours. After that no further oil change will be necessary to perform an oil change for the life cycle of the high-pressure cleaner. If it becomes necessary during repairs, or because the oil has a greyish colour then the oil draining screw should be opened and the oil emptied into a container. The oil is to be caught in the reservoir and disposed of in an approved manner. New oil: 0.25 l - Motor oil: W 15/40.
The first oil change should be carried out after approximately 50 operating hours, then every year or after 250 operating hours. If the oil turns grey or white, you must change the oil. In case of exchanging oil being required, the oil drain screw must be opened above a container and the high-pressure cleaner be emptied. The oil is to be caught in the reservoir and disposed of in an approved manner.
Official Kranzle USA position
As KranzleUSA, our position is that the Recommendations for the K1622TS should be practiced with all of the Kranzle Models. First oil change should be completed around 50 hours (after one to two seasons for non-commercial) and then every year after unless the machine is unused. The prime exception to this guidance is pressure washer models being used in commercial applications. For those pressure washers being used professionally, we recommend increasing the frequency to once per month (for machines that run daily) or once every other month (for machines only a couple days per week).