The solenoid gets REALLY HOT after a short space of time is this ok?
So does mine. You can't touch it, but its been on for days on end sometimes and it's over 3 years old now. (Our R/O is a 450 gpd RoMan unit and does struggle to keep up with the demands placed on it to keep 2 vans supplied.)
Doesn't get as hot in the middle of winter though.
Seriously, if you are worried, go back to your supplier and voice your concerns - good with a followup email to the person you spoke to stating your concerns and summarising his reply making special note of any statements such as "we will replace it under guarantee should it fail" etc.
Spruce