That will be determined by 1 or 2 things or both of them. Believe me I had to find out the hard way just like about everything else I know. Primarily it's the limit of the pump temperature which is most commonly 140 degrees. There are some that go higher. Going over the stated threshold will cause either damage to the pump or a thermal shutoff switch to activate which is a bummer! The other thing is not as obvious. It is the temperature limit of the internal hoses of the machine as well as those you connect to it. If you put really hot water into some machines the hoses may burst or come loose from their fittings causing a mess. Just ask me how I know! This part can probably be modified fairly easy on most machines. Most portables can take some pretty hot water, but the pump and the pressure lines could be an issue.I know on pressure washers, you cannot use really hot water without damaging the pump. I assume it's the same for a porty. Is hot tap water too hot(120ish degrees)?
What’s the aquatec model you’re referring to Jim?My .02 pumptec handles 140°, the aquatecs handle 170° and my hypro 5321 handles 180°. I use the aquatecs in parallel and prefer them to anything else I have ever used. Amazing flow, big jets, biggest droplets hitting the carpet, lighter weight, bulletproof and fast cleaning with no clean streaks like with puny jets.