We had the zr44 and sold a bunch to a company doing smoke testing, they had a guy servicing them all the time, units running hours a pumping hours, usually not so much of an issue.
The ZR45 poor guy lost his mind cause its cob controller not a component based one "old school get spare parts off cpc/rs etc" and they were hacking them to a wireless controller etc etc.
I have found JEM to be good for service, a few old hands there know the units in and out. The issue seems that you have to go the "right" way. Finding a number from an old email was frowned upon.