Hi
Spray aside , I wouldn't put hypo through a decent pressure washer. Sounds like a good machine , if it is has a Honda engine. Although you don't mention the pumps. If you wreck the pump on it it will be poss 500 quid fix.
Do you not have a trolley for,your wc. We have softwash out of your standard pure freedom trolley for years
Just pump a barrel of 0 tds through it when your done . If the pump does go its £60. To swap out.
John