Some like it hot: Getting the right temperature in carpet cleaning

Paul Pritchard answers some hotly debated questions asked by carpet cleaners and machine distributions.

Just what is the big deal about heat, and when is ‘hot’ too ‘hot’ in relation to carpet cleaning? It’s certainly not misleading to emphasise the important role of temperature in relation to the principles of soil suspension. The four commandments (temperature, agitation, chemical and time) we use as professional cleaners determine how efficiently soil suspension occurs.

In regard to temperature, the method of achieving the maximum, consistent temperature depends on the system you employ and obviously something approaching a truckmount califont or heat exchanger system will be the ultimate in terms of efficiency.

Why a truckmount? Iranius’ Law states that for every 8ºC the molecular activity of the solution as well as the fibre we are cleaning will double until it reaches 121ºC (steam). Simply stated this means heat makes the molecules move faster and therefore clean more quickly. The only way to sustain solution temperature consistently, efficiently and safely in sufficient volume to be effective is in a truck mounted system.

So, the hotter the better right?

Well, generally hotter is better, but caution needs to be exercised when approaching temperatures over 90ºC (most household cylinders range between 50ºC -70ºC).

Excessively high temperatures will have a detrimental effect on velvet, plush and hard twist cutpiles (leading to pile distortion) and some acid dyes (used on wool carpets) leading to colour loss, and some fifth generation fibres will void the Stainmaster warranty. Excessive temperature can damage carpet backing causing delamination. There is always a balance in approaching any method – why risk going over 120ºC when the solution will clean just as well at 119ºC as 121ºC?

Remember, steam is generated not just by temperature but by pressure. Our solution is already vaporising at 90ºC and 300-400PSI (depending on altitude). Also, excessive heat has a secondary effect on many carpet cleaning solutions/detergents and cheaper ‘odour neutraliser’ products, causing them to damage pumps, clog jets and ‘streak’ carpets.

Care also needs to be taken with hoses and fittings ‘melting’ synthetic fibres such as heat sensitive polypropylene (using plastic-encased quick connects is a sensible precaution).

What is the best system to use?

The question is not really what each system can reach in maximum temperature, but whether it is able to stay at optimum operating temperature consistently and economically.

Gas powered califonts can certainly reach temperatures exceeding 120ºC easily, however, they tend to ‘peak’ and ‘trough’ according to the thermostatic ranges they are set at. This means that temperature fluctuations occur and temperature drops over long periods, particularly when demand is great.

Also LPG and Kerosene units are bulky, dirty and create the potential for explosion hazards. All the major truckmount brands have moved away from these types of units. Although a few still sell some models with these types of heaters, their inefficiency means most are dinosaurs.

Electric heat exchangers on the other hand are clean and compact and work well in demand situations on portables. They are, however, impractical because of the large amperage ‘draw’ required at the kind of volume required by truckmounts.

This leaves catalytic heat exchangers which are by far the most effective form of heating for truckmounts. These units are compact, low maintenance, clean and effective.

Catalytic heat exchangers work on the principle of building ‘heat’ in stages from the ‘waste’ (read economic) heat of the machines components. This means while heat is a little slower to kick in (two to three minutes) when the machine first starts in the morning (the first stage) once this is done (because water is constantly recirculating through the system and ‘held’ at different heat stages) a consistent heat is achieved even on demand. Just the same as your cars radiator – only in reverse.

So in summary, is heat best? It sure is – but keep within the optimum 90ºC – 100ºC range. If you’re buying a truckmount and weighing up temperature – ask yourself – why do I need heat above 120ºC? Is the system:

  • Efficient?
  • Economic?
  • Clean?
  • Consistent?
  • Space saving?
  • Safe?

*Paul Pritchard is immediate past president of the Carpet Cleaners Association of New Zealand (CCANZ)

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