The owner of Al Ghurair City, in 2009, decided that the nearly 30-year-old facility needed a make-over, including a replacement of the air conditioning system. Trane got the call.

Launched in 1981, Al Ghurair City was built by the Al Ghurair family on an empty plot of land. It was the first modern shopping mall project of its kind in the Middle East.

In addition to the mall, Al Ghurair City includes office space and two-, three- and five-bedroom, fully serviced apartments. It is located in Rigga Road in the heart of Deira and is just a short taxi ride from historical attractions, such as the Dubai Museum and the famous Gold Souk.

With 189 retail shops, 19,085m2 of office space and 343 apartments, it has a significant presence in the area. The facilities are well provisioned with an in-house leisure and recreation club that includes tennis and squash courts, ‘weather-controlled’ swimming pools, basketball and soccer courts and a stateof- the-art gymnasium.

The office space alone is served by three elevators, 24 hours of security, maintenance service and covered parking.

Impressive though this is, how does an owner-operator maintain standards of service and comfort in what is, after all, nearly a 30-year facility? And what of the changing needs of present-day customers and clients, considering the current competitive nature of the retail and commercial market in Dubai, which brings raised expectations of customers and clients?

Considering the two, Al Ghurair City, in mid-2009, decided to add a major new extension, which in the words of the owner, would be modern in every respect. At the same time, giving due consideration to the age of the building, it decided to pay equal attention and care to the established part of the facility. One important aspect was the air conditioning system, which after almost 30 years of excellent service, was clearly in need of replacement. And for this, Al Ghurair City zeroed-in on Trane.

It was decided that the final scope of works would include the re-engineering of the chilled water system, replacement of the watercooled chillers and the installation of an appropriate chilled water control system. Carrying out all these activities, the management concluded, would deliver significant energy savings, resolve issues of an ageing plant and greatly improve operational management of the system.

The original and stilloperational chiller plant comprised four Trane watercooled centrifugal chillers, with a total capacity of 3,000 TR. In addition to the chiller plant, it was clear that ancillary equipment, such as pumps, starters, pipe work, electrics and controls would need to be carefully assessed and, depending on their impact on the system, either upgraded or replaced.

Of utmost importance to the owner was that any work should not interrupt the business or inconvenience the many clients in the building.

The obvious step to mitigate this very real risk was to undertake the majority of work in the winter, but as the load during the cooler months was difficult to predict, no one could say with any degree of certainty what cooling needed to be provided during the change-out. To manage this to the satisfaction of all parties, Trane proposed to first service the existing chillers and have a 1,200 TR temporary cooling system on standby, in the event of a complete shut-down or unexpected circumstances.

Another important aspect was the original R11 lowpressure refrigerant, now a controlled chemical. For many years, this was the preferred refrigerant for lowpressure centrifugals, as its thermodynamic qualities are outstanding. However, with the advent of the Montreal Protocol, which was developed to reverse the damage that was being inflicted on the ozone layer, it is now a substance that cannot simply be disposed of without due care and attention. Trane secured the full support of the Al Ghurair team when it proposed that the replacement project must include the safe removal and disposal of the refrigerant.

Over 30 years, a lot can happen in and around a plant room, and the facility at Al Ghurair City was no exception. Many modifications had been made to the original design and, of course, many other systems had been added in and around the existing installation, making understanding of and, indeed, access to the system a challenging undertaking. This meant that whilst drawings were available, they could not be relied upon to plan the carefully phased nature of isolation, shutdowns and change-outs.

The first major shutdown was undertaken on December 10, 2009, a date that Ra’id Al Jabi, Service Manager for Trane remembers well, as it was the moment when months of planning and preparation were put to the test. However, once the main isolating valves were installed in the evaporator and condenser lines (and observed to hold the enormous pressures in the system) the real work could begin.

To give some idea of just how complex the system had become, Trane’s project team, led by Mark Jolly, along with the very capable Al Ghurair City technical staff, had to locate and isolate around 300 valves before any modifications or replacement could be undertaken. This was an enormous task and required an intensive coordinated effort.

In fact, one of the deciding factors in selecting Trane for the job was that the company demonstrated a clear understanding of the magnitude and complexity of this particular aspect. Had the team got this wrong, the whole project would have been jeopardised.

Other key preparation work included the isolation, removal and replacement of the main headers and the demolition of a 4x7m wall to provide the required access for any future work. On completion, a new wall was built – though this time with a suitable access door to facilitate future service and maintenance work – and rendered to match the surrounding finishes.

Elsewhere, in the crowded two-floor plant room, which was buried in the heart of the building, the pumps were thoroughly inspected and deemed suitable to handle the installed capacity of the proposed new chiller configuration.

To ensure that the electrical side of the equation was brought up to date, all old panels and starters were removed and replaced with Ben Shaw starters and nine TAMCO, 3.3 kV, 400amp vacuum circuit-breakers.

To get the old chillers out and the new centrifugals into the congested plant room forced the team to devise a plan of Rubik’s Cube complexity and precision; after all, the chiller change-out had to be undertaken without taking the cooling plant off-line. To further complicate matters, the main plant room was located not just deep within the building, but up on the third floor. Trane engaged the services of Transport Technics and Services (TTS) International who specialise in the handling, transportation and installation of heavy and oversized cargo by land and sea. Trane had previously worked with TTS on the equally challenging chiller installation of the Burj Khalifa, a few years earlier.

But of course, before the chillers could be dismantled and removed, the refrigerant had to be captured and disposed of, in accordance with recognised industry standards. To assist with this important aspect of the job, Trane partnered with EnviroServe, who are a registered company, established under a Professional License for Pollution and Environment Protection Services.

The Trane services team worked closely with EnviroServe to recover over 1,800 kilogrammes of CFC-11; equivalent to about seven drums.

Stuart Fleming, Managing Director of EnviroServe, said: “All procedures were followed to complete the safe disposal of the old refrigerant. There was no release of the potentially harmful chlorofluorocarbon to the atmosphere nor did any venting occur while undertaking the assignment. The CFC-11 will eventually be transported to Linde AG, Industrial Gas Division in Germany, for destruction, once the license and authorisation are obtained and sufficient volume is achieved for shipment. The refrigerant will be transported under the Basel Convention as ‘hazardous products’.”

Nigel Hawley, Territory Leader, Trane (Middle East, India & Africa), added: “Our commitment to safe environmental practice remains, regardless of our contractual scope and obligations. We are dedicated to safe and ethical business practices for a better and greener tomorrow. EnviroServe is the only dedicated refrigerant reclamation company in the Middle East, and we were happy to partner with them to reclaim, recover and dispose of potentially harmful refrigerants in a safe and environmentally responsible manner.”

The remains of the old chillers and associated scrap were also safely disposed of using another qualified vendor. Though Trane’s scope of work was limited to loading the old chillers onto trailers, they ensured that the nominated sub-contractor took due care to dispose of the material in an environmentally responsible manner.

In addition to the electromechanical work, Trane installed its Refrigerant Recovery system and storage tank in the plant room to avoid potential venting issues, even though the newly installed chillers used the environmentally recognised R123 low pressure refrigerant. A LoVac recovery pump is also on standby. This recovery system is very popular due to its fast recovery rate, its light weight and ease of operation. In addition, a refrigerant monitor was also installed, in accordance with ASHRAE 15 guidelines.

To ensure that all components worked as an optimised system, Trane upgraded the existing Tracer Summit chiller plant manager with custom graphics. This now allows users easy access to various parameters of the equipment, such as chilled water and condenser water pumps.

In the discussions leading up to the award of the project, the Al Ghurair team had expressed a strong interest in ensuring that they would get a chiller plant that would be reliable, durable and efficient. The new chiller configuration comprised two CVHG-670 and two CVHG-1100 EarthWise simplex water-cooled centrifugal chillers. Net cooling capacities are 515 TR and 950 TR respectively at 7.2/12.8ºC chilled water temperature range and 35.0/41.0ºC condenser water temperature range.

Replacing a whole chiller plant is a major investment, and the client was obviously very interested to have an idea on how quickly his investment might pay back. Using Trane’s Trace 700 energy-modelling software, which took into account many parameters, including the efficiency of Trane’s new EarthWise centrifugal chillers and the current rate for electricity, it is estimated that, over their 30-year life, the chillers will result in a saving of around Dh10 million, which comfortably exceeds the cost of the entire replacement project. In addition, the owner may look forward to an increase in capacity and significantly reduced service and maintenance charges, not to mention improved reliability.

As mentioned earlier, Trane did put in place a temporary cooling plant for any unexpected eventualities? However, the old chillers, which were serviced just prior to the job, produced the required capacity during the change-out, and the isolation valves held as planned. As a result, there were no ‘unexpected eventualities’. So, thanks to proper planning and execution, the temporary cooling plant was dismantled and shipped back to the yard without seeing a minute of operation.

Ramzi Jaber, Trane’s project engineer, confirmed that the commissioning of the system was completed on April 1, 2010, which was slightly ahead of schedule, on budget and with no interruption to the client’s operations.

Climate Control Middle East visits the Aldes Middle East factory, which opened in the thick of the downturn and is determined to see the tough times through. Photographs: B Surendar

It is early July, and the weather is unrelenting. Protected from the sun, though, a group of workers are beavering away near a batch of circular sound attenuators, in the Aldes Middle East factory, in Sharjah International Airport Free Zone.

The attenuators, destined for Qatar, are large – 1.8 metres in diameter, imposing and command attention. But in relation to the 8,000-square-metre expanse of the factory, they look small.

The factory, which opened early this year, consists of three sections: a cutting section, a steel assembly section and an aluminium assembly section. It is here that Aldes makes 85% of its products for the GCC market. The range includes fire dampers (motor and smoke), VAVs, VCDs, sound attenuators, grilles, diffusers and louvres.

Gaetan Pierrefeu

In addition to standard specifications, the factory produces non-standard, customised items. The circular sound attenuators bound for Qatar, in two batches of 40 each, are examples of customisation. “It is common for us to produce customised items,” says Gaetan Pierrefeu, the Managing Director of Aldes Middle East. Sometime ago, we delivered similar large sound attenuators to a big project in Fujairah. Customising seems to be important for customers here.”

Owing to the demand for customisation, Pierrefeu says, it is impossible to ascertain how many products the factory can produce every day. In the case of the batch for Qatar, owing to the size, the shop floor personnel can produce four a day. If square in shape, they will be able to produce 25 a day, Pierrefeu says. Likewise, in the case of an order for 2,000 VAVs with five dimensions, the factory can produce 200 pieces a day; however, at times, it gets an order involving 50 dimensions, which makes it impossible to determine the number of pieces the factory can produce in a day. “Customisation is our strength, though,” Pierrefeu says. “We don’t manage workflow based on the number of items we need to produce. One week to another, the production organisation is completely changing.”

Keeping this in mind, Pierrefeu is trying to develop minimum skills levels for the personnel, so that he is in a position to move people from producing sound attenuators to VAVs. “Flexibility is key,” Pierrefeu says. “In sound attenuators, you don’t have a lot of welding, but fire dampers and VCDs demand a lot of welding.”

Flexibility is important from an employability point of view, as well. Since it is possible for the shop floor personnel to migrate from one task to another, the factory is able to avoid wastage of human resources, Pierrefeu says. This is particularly crucial in the downturn – it is able to maintain production with a leaner workforce.

Planning for the factory started in the end of 2006. Construction started in 2007, and 90% of the factory became ready by the middle of 2009. At the time of planning, Aldes and Pierrefeu did not anticipate the severity of the downturn. Today, Pierrefeu admits that the downturn is impacting the factory. “Compared to initial plans, the production capacity is three times what we are currently doing,” he says, looking rueful. “The market is down in Dubai, so we are working on the northern Emirates and Abu Dhabi.”

A saving grace at this point in time is Qatar, says Pierrefeu. “Qatar is booming for us,” he says. “We have multiplied our sales by three in Qatar. As for Saudi Arabia, it is the next big market. As of now, we are almost zero with regards to Saudi Arabia, though.”

The downturn, Pierrefeu says, is all the more challenging, because people are price-oriented. In his view, a lot of people have invested capital in setting up factories that manufacture similar products, which has led to oversupply of the products. However, most of those products are not reliable, Pierrefeu says. “We, too, make our products locally, but we have a good technical approach. What is missing in the market is regulation, and that’s impacting us.” Pointing to the example of France, Pierrefeu says that while designing a school there, it is mandatory to have air renewals at five times an hour for a standardsized classroom. This will determine the type of grilles and fans, the dimensions of ducting and the performance of the system. A grille is not just a grille; it directs and regulates air flow.”

Alexandre Benoit

Regulation is not just about the product, adds Pierrefeu’s colleague and Marketing Manager of the company, Alexandre Benoit. It is also about whether the product is properly installed or not. “The regulation for ventilation started 40 years ago in France,” he says. “Regulation defines how much air should be extracted from a toilet or a kitchen. It defines a minimum level of working conditions, a minimum level of quality

Saying that it offers an efficient solution for demanding refrigeration applications, with its unique scroll design and manufacturing process flexibility, Danfoss has released its new range of MLZ Refrigeration Compressors. The series includes 11 models of medium temperature scroll compressors designed for commercial refrigeration applications.

According to Danfoss, the compressors are purpose-engineered for refrigeration, and offer customers the possibility to specify cooling capacities from 3,800 to 30,000 watts and to select from global voltages and frequencies as well as any of the common refrigerants (404A/134a/507/22). The MBP scroll compressor range will complement the company’s existing line of MT/LT hermetic reciprocating compressors, condensing units and package units, and will be available in compressor, condensing unit, and package unit designs.

The manufacturer claims that the compressors reduce overall costs in the following manner:

• The hybrid-wrap scroll design will reduce energy cost in normal operating conditions and deliver high capacity and an optimised pressure ratio for refrigeration applications.
• In varying cooling cycles (such as ice machines or during pull down), the Danfoss patented Adaptive Control system Danfoss ensures that the scrolls will have continuous optimum axial pressure, thus reducing leakage, while minimising friction.
• A patented overload protection system will reduce the system’s down time.
• Its multi-refrigerant smaller and lighter design and local/global availability will help reduce installation costs.
• Reduced noise due to a check valve design translates into less cost for lownoise applications.

Product applications :

• Cold rooms
• Milk cooling tanks
• Compressed air dryers
• Ice machines
• Soft serve ice cream machines
• Shake, slush, and frozen beverage makers
• Process chillers

New York-based Kathabar Dehumidification Systems has launched KDS Solar liquid desiccant systems, which utilise solar hot water for economical dehumidification of outdoor ventilation air that is typically 30-50% more energy efficient than dry desiccant systems.

According to the company, making use of solar heat can lead to increased energy efficiency and significant utility savings for applications requiring high amounts of outside air. By incorporating KDS Solar, buildings can achieve large-scale energy savings in air conditioning.

In addition to using solar hot water as a heat source, KDS Solar can use low-cost cooling tower water as a coolant source. Kathabar enthalpy recovery devices are available for additional energy savings.

Kathabar Solar is valid for a wide range of applications at industrial, commercial, institutional, and green/LEED facilities with as low as 20% relative humidity.

According to the company, Kathabar dehumidification systems deliver precise and reliable temperature and humidity control to a wide range of industrial, commercial, and institutional applications regardless of air inlet conditions. Kathabar dehumidifiers also provide critical bacterial control by capturing most airborne bacteria, viruses, and mould.

All Kathabar equipment is made of Fibre Reinforced Plastic (FRP) with industrial grade construction to provide less maintenance and long equipment life. Kathabar liquid desiccant systems, most efficient when cool or cold dry air is desired, can handle airflows from 750 to 84,000 CFM, the company said.

Güntner’s latest innovation in the world of heat exchange is its new line of condensers. The Microox GVX Condenser Line is a breakthrough in the history of condensers. The Güntner Microox heat exchanger is the perfection of the micro channel technology and consists completely of aluminium. This was achieved by adjusting the wall thickness of the heat exchanger modules for higher refrigerant pressures. All Microox heat exchangers are produced in modern production lines at Güntner.

Key facts about the Microox Low refrigerant charge:

• Up to 50% less refrigerant charge compared to capacity
• The regulation EC 842/2006 (F-Gas regulation) prescribes leak tests, depending on the refrigerant charge of the installation
• Less leak tests are necessary at a lower refrigerant charge, with reduced CO2 equivalent
• Corrosion resistant: the heat exchanger consists completely of aluminium, with no galvanic corrosion, powder coated
• The GVX Microox technology consists completely of aluminium and is lightweight and easy to transport and mount compared to conventional heat exchangers

Wall mounting:

• The GVX weighs up to 30% less and is well suited for wall mounting, and saves costs
• Mounting to walls with low wall-bearing capacity is possible
• No additional wall mounting brackets required
• Wall mounting beam with or without vibration dampers

Floor mounting:

• All units are also suitable for floor mounting and can be installed directly on the floor or on U or T beam
• Enough room for sufficient air supply

Using a sheet metal laminate with a thin foil on one side, Antiphon AB has introduced MPM (metal-polymermetal) foiled – a new product for structureborne sound damping. The core material consists of two zinc-coated sheet steel, laminated with an acoustic inner layer. This, says the manufacturer, can obtain superior structure-borne sound damping, and can be used to reduce vibrations without increasing the weight of the construction. It can replace already existing materials. Aluminium is also an option as core material.

Product features:

• MPM foiled is available in a wide variety of foil surfaces, colours and patterns.
• It is delivered in format sizes of maximum dimension 1,250x3000mm.
• The thinnest sheet is 1.04mm, where the system consists of two sheet steel of thickness 0.5mm, laminated with a 0.04mm acoustic inner layer.
• For aluminium, the minimum thickness is 1.44mm. The maximum thickness is 6.1mm.
• It is delivered with a peelable protective film.
• It can be worked with methods normally used within the industry, to cut, press and punch.
• Mechanical joints, bonded joints or combinations are of jointing methods used.
• It can be recycled as standard sheet steel.
• When bending is required, special instructions might be needed.
• Welding and laser cutting is not advisable.

Applications :

The durable surface complies with the demands concerning flammability, making it adaptable to marine applications and interior design, such as cabin and corridor panels.

Interior surfaces for the automotive sector, appliance housings, doors and shop lay-outs are other possible application fields. It allows the use of laminated sandwich systems in more visible environments as a decoration material, where sound damping is needed, thus fulfilling the dual demands of aesthetics and functionality.

Touting them as high capacity, but small footprint products, compared to their power density, Güntner Middle East, of the Güntner Group, has introduced its new GFD and GVD units – the V-shape coil drycooler GFD and V-shape coil condenser GVD.

With this, claims Güntner, it has enlarged the power spectrum of its V-shape coil drycooler and condenser series (GFD and GVD). The V-shape coil drycooler GFD can be designed with a capacity of up to 2MW per unit. The GVD and GFD units come in eight basic models. They offer high flexibility of fin and tube geometries and a large variety of heat exchanger coils, the company adds. It enumerates the following application benefits:

• An optimally suited unit can be designed for each application.
• Due to the Güntner floating coil system, the coil can expand without straining the refrigerant-carrying tubes and the unit is protected against refrigerant losses due to leakages.
• The units are equipped with air-side separation sheets for an optimal fan control. Additionally, the units are suited for all types of fan control – they can be equipped with AC fans (alternating current) or EC fans (electronically commutated).
• The condenser GVD can be designed to an operating pressure of 41 bar on request. Thus, the unit can also be operated with refrigerants replacing R22, for example, R410A.
• Optional features and accessories are available for both series.
• The units are delivered ready for operation, thus obviating installation of individual components on site. Only two crane lugs are required per unit for transportation and mounting. The crane lugs can be moved, so that transportation by crane is possible without cross beams. Despite their size, the units are suited for transportation by truck.

Drawing attention to the lifethreatening trend of intentional inhalation or “huffing,” by children and young adults from access ports on residential and light commercial air conditioning and refrigeration equipment, Airtec Products Corp, manufacturer and importer of HVACR products, has announced the launch of Novent, tamper-resistant locking caps. They claim that the caps aid in the prevention of refrigerant theft and leaks into the environment.

According to Airtec, the corrosionresistant, aluminum-shrouded brass locking caps screw on to standard Schraeder valves. They also comply with the International Mechanical Code (Section 1101-10) and International Residential Code (Section M1411-6) that now mandate tamper-resistant outdoor access ports for all new AC/R installations.

Airtec claims that the patented locking caps, which can only be installed and removed with a special screwdriver or MultiKey key-ring wrench, are available only through wholesale HVAC/R distributors. The locking caps and screwdrivers are colour coded – green for R-22 and pink for R-410A – to assist in preventing accidental refrigerant mixing, and a universal silver is available for use with any refrigerant.

Product features

• Oil and sealant-resistant neoprene O-ring seals tightly to eliminate refrigerant leaks to the environment.
• Integral torque limiter prevents overtightening.
• Precision-machined, high-grade aluminum-shrouded brass fitting resists crushing and removal without a Novent key.

Airtec Products, which is the global distributor for Novent states that the products are sold in two packs, 10 packs and 50 packs of pink, green or silver 1/4-inch-thread, and a pink cap with 5/16-inch thread for imported R-410A equipment, which complies with EEC requirements.

HVACR aftermarket products manufacturer Cliplight Mfg, has introduced three Flash professional refrigeration system leak detection kits, that include three “no mess” cans of Flash, a reusable charging hose, an ultraviolet (UV) detector light and a carrying case.

Cliplight claims that the vacuum-packed, one-time use cans can each treat up to one five-tonne unit or 64-ounces (1.8-litre) of system oil. Also, unlike other dyes on the market, states the manufacturer, Flash does not use an injector or polyolester (POE) oil as a carrier. Instead, it uses Cliplight’s own Dry R drying agent, combined with the charging hose’s 29/1,000ths orifice to instantaneously mist the dye into the system, keep it stable and prevent crystallisation.

According to Cliplight, the kits vary by UV fluorescing light function and illuminating range as follows:

• Dual Pro 82 Kit uses the Cool Dual UV/White LED Light that functions both as a close range UV dye detector and a conventional flashlight in an aluminum casing, with an anti-drop wrist strap. The light includes 21 UV LEDs, 20 white LEDs and 4-AAA batteries.
• Mini Pro 84 uses Cliplight’s Vector 4 UV LED Light with patented focal lens technology for inspections up to 15 feet. The Vector 4 has a fourhour continuous use life and a 9V battery internal energy management system, ensuring full UV output throughout the battery life, with an intermittent on/off switch and orange 10-minute low battery warning light. It also includes an anti-drop wrist strap and 9V battery.
• Maxi Pro 87 uses Cliplight’s Vector 7 UV LED Light that focuses seven LED beams into one light source extending up to 20 feet. The cordless Vector 7 is rechargeable with a five-hour continuous use life and NiMH, 1,800-Ah battery that has no charging memory precautions. The light includes both an AC/ DC charger and low battery indicator.

Other leak-detection features of the kits include:

• Universal dye compatible with all refrigerants and oils
• No contaminating moisture introduced to the system, as Dry R is used as a dye carrier and stabiliser instead of POE oil
• No clean-up, hand contact, storage or injectors needed – system refrigerant fills the can, mixes with Flash and instantaneously distributes it throughout the system
• Reusable charging hose is cleaned automatically for the next application from solvency of system refrigerant exiting the Flash can
• Charging hose’s 29/1,000ths-inch throttling orifice guarantees no dye liquid will reach the suction line of the compressor
• No UV enhancement eyewear needed, as all kits use professional UV leakdetection lights
• All kits include service stickers for quick ID on future servicing
• Customer service support

California-based Electro-Chemical Devices (ECD), manufacturer of liquid analytical process instrumentation, has introduced models S10 and S17 Universal Toroidal Conductivity Sensors, which the company claims, enable highly accurate conductivity measurement. The inductive sensors feature a standard measurement range from 50 to 1,000mS. Model S10 is an immersion or insertionstyle device and Model S17 is a valve retractable-style device.

According to ECD, the sensors are built with the toroids, in line with the axis of the sensor, instead of perpendicular to the axis, as is commonly employed. This allows for the smaller diameter and shorter inductive path length, that is beneficial for the compact design.

With a compact 0.75-inch (19.05 mm) diameter sensor body design, the conductivity sensors, claims ECD, are ideal for use in tight places with crowded piping and equipment locations, such as, cramped industrial process and manufacturing operations.

They operate effectively in pipes as small as 1.5 inches (38.1mm) in diameter, which is up to five times smaller than typical conductivity measurement devices. Fitting into an existing pipe, without the need for re-plumbing the flow cell, is an added advantage.

Product features and applications:

• The sensors feature Kynar PVDF plastic body that is sealed, making them suitable for harsh industrial applications, including resin bed regeneration, acid and alkaline scrubbers, metal-plating baths and wastewater treatment.

• They can withstand harsh liquids such as acids and coolants, where corrosion and scaling pose problems.

• The models are compatible with ECD’s transmitters and controllers. The T23 and T28 loop-powered transmitters can be used either with NEMA 4X, T23, or explosion-proof T28, area classifications. The C22 controller has dual-sensor inputs that allow any combination of measurements and outputs to be combined in one controller.