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Servicing for energy efficiency

23 October 2009 by
Servicing for energy efficiency

Commercial catering equipment is built to withstand heavy-duty use but it needs regular servicing in order to perform efficiently throughout its expected life cycle. Diane Lane examines the cost of poor maintenance.

A worryingly high proportion of kitchen equipment is not maintained on a regular basis, despite the fact that a routine visit by a service engineer will fine-tune equipment so it runs at peak efficiency and reaches its maximum life expectancy.

Too many operators balk at the cost of a service contract but perhaps what they should be taking into account is the cost of not properly maintaining their equipment. Everyday wear and tear leading to instances such as a broken oven door gasket, a clogged burner on an open top range or a loose oven door hinge can result in significant increases in the appliance's energy usage.

Like most people involved in the specification and installation of commercial kitchen equipment, Kevin Tyson, director of design consultancy Hepburn Associates and member of the Foodservice Consultants Society International, is an advocate of planned maintenance.

"Planned maintenance is a proactive strategic service programme designed to maximise equipment performance over its entire life cycle, which ultimately contributes to a company's bottom line," he says.

"Rather like servicing a car, there are some parts that will require replacement during the life cycle of the equipment but, more importantly, many will last significantly longer if cleaned and serviced regularly."

"Car servicing now has emissions testing, to ensure it is minimising its harmful environmental impact, but catering equipment can also cost both the owner and the environment significantly more in energy wastage if it is not properly maintained."


Cleaning is a key part of preventing equipment inefficiency or even breakdown. Steve Elliott, managing director of Serviceline, lists some problems that can be avoided with proper cleaning: "Food spillage can block the burners on gas ranges and cause an inefficient burn. Under solid tops, food build-up affects the distribution of heat, is unhygienic and wastes heat. With fryers, the gunk that collects in the cool zone traps heat and wastes energy, and food build-up in ovens wastes energy and can aid corrosion."

Poor cleanliness also costs when an engineer's time is taken up cleaning muck off the back of a range to get to the retaining screws or bolts, or moving dirty plates or pans out of the way, says Elliott.

"Engineers are usually charged to caterers on a timed basis, be it hourly or per 15 minutes, and a clean kitchen and clean equipment means the engineer can get on with their real job straight away, with minimal time and cost. Money is wasted when the engineer has to clean up," he explains.

Besides the cleaning, which is relevant to all equipment, there are three other areas identified by Tyson as critical when it comes to a preventive maintenance plan - water-using equipment, such as combi-ovens and dishwashers, refrigeration and ventilation.

"Installing a good water filtration system allows operators to take their first steps toward reducing breakdowns and increased energy use," he says.

"The meeting of water and heat in a boiler-type steamer always leaves behind scale deposits, which will coat the heating elements. Just 6mm of scale on an element can cause that piece of equipment to consume up to 35% more energy and energy costs can be the most costly part of ownership. Part of a good maintenance programme will be checking and replacing clogged filters."


When it comes to refrigeration, it is estimated that a partially blocked condenser can increase energy consumption by up to 23%, definitely not a good idea on equipment that runs 24 hours a day, seven days a week. Staff can play their part by keeping the covering grills and the area around them dust-free, but the condensers themselves should be cleaned by an engineer on routine visits.

Worth considering, too, says Tyson, is that besides the extra energy costs incurred by not keeping condensers and grills clean, if the unit has not held its temperature, the food inside it could spoil, which could cost considerably more.

A ventilation system is not exempt from the requirement for regular maintenance to run at optimal levels and if yours isn't working correctly, then you end up with an extra hot kitchen.

"A couple of common things that can cause hoods to fail include broken exhaust fans and ducts, and exhaust fans that are clogged with grease," says Tyson.

"The make-up air supply - air that is supplied to the kitchen to make up for the air exhausted - also has a dramatic effect on hood performance. Too much or too little make-up air will cause the hood to fail, as will make-up air that is blowing directly on the front of the exhaust hood.

"If too much smoke is building up in a kitchen, or if the system seems like it's on overdrive all the time, a rebalancing by a trained technician is likely to be required. A rebalance ensures the system is keeping the kitchen safe and that the fan is not using up excessive energy by working too hard. Outside doors that are hard to open because of suction, or that blow open by themselves, are a sure sign that it's time to get an air rebalance."

One who knows the importance of routine maintenance is Alan Tuckwood, head of catering and physical education for HM Prison Service and Public Sector Caterer Catey winner in 2006. Five years ago, he initiated an unprecedented five-year contract covering the catering equipment in English and Welsh prisons. The immense contract, held by Falcon Foodservice, involves about £30m of catering equipment manufactured by Falcon, Rational, Winterhalter and Groen spread over 129 sites and serving about 82 million meals a year to 74,000 prisoners.

Five-year warranty cover is provided by kitchen and refrigeration maintenance specialist Serviceline, supported by Winterhalter's service team, which specialises in warewash maintenance. Now the equipment is heading out of its original warranty, Tuckwood's next step is negotiation of a further maintenance agreement for another two-and-a-half years.

"By adopting a maintenance strategy we are extending the life of equipment by 50%," he says.

"That means fewer burdens on the taxpayer and a maximising of the green credentials of the equipment such as energy efficiency and water consumption."



All warewashers have filter systems fitted to trap food debris but Hobart stresses they are not waste disposal units, and plates should first be scraped of any excess food then rinsed to prevent clogging of the filter.

Gas appliances require the correct gas pressures and levels of air-to-gas mixture in order to achieve combustion. According to Electrolux Professional, low gas pressure can cause incomplete combustion, which can in turn lead to inefficient heating, owing to burners getting covered in soot.

Lincat advises you to look out for worn door seals that allow heat to escape and mean more energy is needed to achieve the operating temperature.

Poorly fitted or maintained wash rinse arms will, says Meiko, lead to more water and chemicals being used and extra energy needed to heat up the additional water.



A heating element thick with limescale can add 50% to energy consumption to reach temperature. On the steel surfaces of combi-ovens, for example, limescale build-up appears as a white or grey powdery coating.

Ice build-up

Ice can slowly build up on the evaporator in the cold room - where the cold air is blown from - particularly at the back or sides. This uses more energy and the ice effectively insulates the system and makes it work harder. If the ice has formed a stalactite, call an engineer.

Broken door seals

Door seals should be replaced when worn or damaged. More than 20% of the heat can be wasted due to a split seal on an oven and 10-15% of energy is wasted by a split seal on a refrigerator - more on a freezer. Seals on combi ovens are particularly susceptible to damage as pans are loaded in or out. Water leaking on to the floor under the combi is a giveaway.

Thermostat calibration

Thermostats are notorious for breaking down and an engineer should check they are calibrated correctly every six months, or at least annually.

  • On hot cupboards: It's not uncommon to see staff leaving the sliding doors open because they are getting too hot owing to a faulty thermostat.
  • On ranges: As well as adjusting gas burners so that they burn blue with no yellow, engineers will also calibrate the range so that the temperature selected for the oven matches that on the thermostat.
  • On fryers: Telltale signs of a faulty thermostat are if clean oil begins to smoke at normal temperature settings. If the thermostat trips out, you may be able to reset it, but don't do that more than once. Call a service engineer to check it.
  • On refrigeration: It takes 20% more energy for a fridge to operate at 3°C, rather than the desired 4°C. The engineer will check that the visual display matches the thermostat.

Source:Serviceline,01438 363000

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