Commercial carpet poses unique challenges for cleaning technicians. Since it is usually glued directly to the floor, moisture has no place to go but up (after a couple of days). Capillary action has the ability to overcome gravity.
Industry surveys indicate more professional carpet cleaners use hot water extraction and bonnet cleaning as their primary method than all other types of cleaning combined. Here are some of the most common mistakes made by technicians using self-contained extractors and bonnet systems:
1. Failure to apply appropriate spotting chemistry. Using the wrong spotter sets stains. Paint, oil, tar, chewing gum, adhesive, shoe and nail polish, etc., require a solvent for removal. Coffee, tea, rust, and water stains respond best to acidic cleaners. Always start with a light application of the appropriate spotter. If you are uncertain of the spot, begin with an all-purpose water base spotter. Blot carefully to the center of the stain to avoid spreading it. The objective is to transfer the spot into a white terry towel. If the spot persists, switch to a solvent cleaner and blot, and then rinse with an acidic spotter. With the acidic spotter, use a light spray and blot with a towel. An acidic rinse agent diluted 1: 5 with water is very effective on water, coffee, and tea stains. By cleaning using these three steps, many stains will be pulled apart a layer at a time with the corresponding chemistry.
2. Failure to minimize aggression. If a spot fails to respond to a process, interrupt the cleaning and change chemistry. The spot is indicating that it is not going to respond to the currently used chemistry. Using the trigger-spray head to scrub the spot is fairly nonabrasive. Scrapers, heavy brushing, and scrubbing can all distort the carpet fibers.
3. Failure to pre-examine or pretest the carpet. Inspect the carpet first for any noticeable damage. There is no reason to waste time with burns or color loss. You may want to clean a small test area containing the heaviest soil. This will give you an indication of which process and chemicals will work best. It also can help suggest estimated cleaning times.
4. Failure to pre-identify soils and fiber construction and to pre-vac heavy soils. Wool carpet requires cleaning at a low pH. Olefin (common in level-loop glue-down carpet) responds best with a fiber-specific preconditioner. Restaurant carpets respond well to an enzyme preconditioner. Be prepared with the appropriate cleaners. If the carpets have not been vacuumed, then proceed with a thorough vacuuming. This is especially true when there is heavy dust coming from a shop area or mud from outside. If you don’t pre-vac, you may end up with a heavy concentrate of partially dissolved soil at the base of the carpet.
5. Failure to maximize temperature, minimize moisture, and minimize chemical. Elevated hot water extraction temperatures will facilitate grease removal. Low moisture pre-sprays or a pre-scrub will loosen soil. Excessive moisture over-wets the carpet and often produces wick back. Chemical residues will later attract soil.
6. Failure to pre-spray or pre-scrub prior to extraction. Heavy soil conditions require aggressive cleaning. Commencing hot water extraction with a 1 percent cleaning solution circumvents necessary detergency and agitation. In other words, if the carpet is heavily soiled and you start immediate cleaning, the carpet will be wet. Applying a pre-spray to a wet carpet causes the chemical to be immediately diluted by perhaps another 50 percent. Repeated machine passes are often required whenever a pre-spray was omitted. Now the carpets are wetter than necessary. A pre-spray, with sufficient dwell time will normally handle medium soil. A pre-scrub with a bonnet/brush or aggressive bonnet will provide the additional agitation to loosen heavy soil.
7. Failure to adjust machine speed to match soil conditions. The heavier the soil, the slower the machine must be operated. Multiple passes may be required on heavy soil. Professional cleaners continuously monitor results and adjust machine speed and chemistry. Most self-contained extractors have a clear dome or sight glass to monitor soiled water return. Operators can observe when desired levels of cleanliness have been reached. Damp carpets hide soil conditions. By continuously comparing the previously soiled traffic lanes with the clean edges, you will be able to appraise results. Cleaning is performed by a technician with a machine but begins and ends with the eye. Professionals work difficult areas to perfection!
8. Failure to monitor hot water extraction performance. Power head brushes effectively distribute cleaning solution so plugged jets and skips are not easily identified. By periodically inspecting the spray pattern on dry, unsealed concrete or tipping the machine back and observing the spray pattern from 3 feet away, plugged jets can be identified. Jets will eventually hollow out with use and spray the solution in a cone instead of a fan pattern. It helps to record and remember the spray pattern width, depth, and pressure when the machine is new, so you have a comparison. Weak pump pressure, air leaks in the suction side, clogged lines, bent hoses, or plugged suction strainers will all reduce pressure. Operators should listen for proper bush rotation and be able to feel the rpm vibration. If the power-head brush malfunctions, service the machine. Vacuum leaks can occur in the dome or suction hose. Hoses can also plug with obstructions. Carpets vary in ability to absorb water, so recovery rates will vary. However, machine service is required whenever recovery rate is below 80 percent (8 gallons of soiled effluent recovered for every 10 gallons of fresh solution applied).
9. Failure to adapt cleaning systems for interim versus restorative cleaning. Interim methods, such as spin bonnet or dry foam shampoo, produce suitable results on medium soil but lack the ability to flush and rinse impacted mud, soil, and cleaning detergents from the carpet base. When interim bonnet cleaning fails to produce satisfactory results, restorative cleaning will be necessary. Professionals are able to observe carpet soiling conditions and adjust with the proper cleaning process. Whenever carpets are extracted, results will be dramatically improved by immediately following with a dry bonnet. The extra dwell-time loosens soil, and the bonnets will pick up this residue. Stains that do not respond well to extraction may be easily removed with a bonnet. Skill is required in assessing when to stop extracting an area and leave the rest for bonnet cleaning. Subsequent bonnet cleaning will normally improve the carpet appearance 10 percent to 20 percent. Bonnet cleaning must follow extraction within 20 minutes, or the carpet will start to dry and the synergistic effect will be lost. If the carpet is prone to brown-out, use a light spray of acidic rinse prior to bonnet cleaning and dry with an air handler.
10. Failure to balance a total maintenance program. Carpet construction, color, soil conditions, and frequencies of cleaning all affect the balance/mix of cleaning routines. Darker carpets can be spot cleaned several times before bonnet cleaning is required. Light carpets may need cleaning after just a couple of spot cleanings. Monitoring soiled traffic lanes can help gauge soiling conditions. Some carpets require extraction after three bonnet cleanings. Others can be bonnet cleaned a couple of dozen times before extraction is required. A professional will need to observe soiling and cleaning results and establish a suitable routine.
By Anthony Trombetta
