Where do you come from, I have a similar set up with a better quality Whurlaway
I also look after a fleet of them for a national company, I am a time served plant engineer.
From memory the tech clean has not got a grease point like whurlawys have, but nozzles need changing on all high pressure water equipment as the hole in the nozzle becomes worn bigger giving a reduction in pressure. I'ts also for this reason that nozzles are matched to the pressure washer litres per min (flow) and pressure usually in bars
replacement nozzles should cost about £4/£5 each
How old is your tech clean as the early ones where no more than wheel wash swivel and in my opinion wern't up to the job