The problem you will experience doing this is driving between jobs the water in the hose reel will go cold as there will be no circulation through it , if you can run the water through the reel and have your return to tank feed plugged into that that way the water will be red hot straight away . I had an ionics thermopure system and sold it due to a number if issues , I now have a normal ionics cold system with the grippatank 9 kw two hot pole heat exchangers it works so much better than the ionics set up , I also experienced no end of problems with the ionics systems return to tank pressure valve it kept jamming shut replaced loads of them at about £65 a go I think they were , as per usual ionics didn’t want to know only prepared to sell you a new valve rather than accept it was a warranty issue ,