Hi Tony
My approach to HWE carpet and upholstery cleaning is that all of the work in the
CHAT Cleaning Pie ie
Chemical,
Heat,
Agitation and
Temperature, is carried out as required. Extra to this is the Pre Vac and the Rinse. As the soil has been broken away from the fibre/yarn, heat, when rinsing, is an insignificant requirement. My chosen pre-sprays, whether detegent or microsplitting, are formulated so that only a freshwater rinse is required ie they are free rinsing.
Having said all this, when it comes to HEAVILY soiled carpets, it is not always possible to clean in this way as the CHAT process may not sufficiently break down all of the soil/fibre bondings with one application. A heated rinse in these circumstances is of great benefit. I prefer not to be involved with this market sector.
There is a general opinion that a heated rinse will accelerate the initial stage of drying, and certainly I would support that view. I do, however, have two concerns.
1) Too hot water in the rinse tank can be detrimental to the pump.
2) Excessively too hot a rinse, especially at elevated psi, can, and does, damage the twist in some yarns, especially those at the lower cost end of the market. Sometimes, this damage may not be immediately apparent and only manifest itself some time later.
In my own machine, I use hand hot water for the rinse, typically about 50
oC. If not available, I will use cold water from the tap with no obvious disadvantage. I typically run between 170 and 220(ish) psi. For the way I work, drying is not a problem.
Safe and happy cleaning
Ken