Hi,
If possible I would fill the HF container with cold water and this will warm as the hot tm solution hits it.
The idea is this. Solvents can flash off or evaporate more quickly when heated. Feel free to experiment. So with this in mind not super heating the solution may help keep more of the solvent on the carpet to provide a little better clean. Your not going to hurt anything by not doing this its just my recommendation to get the best results. Pleae let us know if your findings are different. I dont mind being corrected if Im wrong.
Now when you rinse with tm hot water I think this will provide the best result for you.