Cleaning the Coils – the right cleaner for the job:

Following up an article which appeared in Service Engineer September 2000 posing some of the problems associated with coil cleaning, Janey Parker of Advanced Engineering Limited provides some effective answers…

The majority of coil cleaners currently available come in either liquid or powder form. If they are in liquid form then they will need diluting or be ready mixed. Likewise, those in powder form will need mixing with water. In typical applications these will be applied using a low-pressure sprayer with a wand attachment. It is important that the pressure of spray jet is not too high, as there maybe a risk of damaging the delicate fins but it should be able to allow the cleaner to penetrate the coil.

Typically there are five types of cleaner – acid, alkaline, solvent, detergent and disinfectant.

Acidic Cleaners

These can be very effective at removing dirt from a coil but they must be used with caution. Acids are corrosive to human flesh, clothes and the metal surface of the coil. The can also give off unpleasant fumes. It is essential that acidic cleaners are rinsed thoroughly from the coil, that they are used in well-ventilated areas and all surrounding furniture, either moved or protected.

Safety measures must be followed when using these cleaners, including protective clothing and eye protection.

Acidic cleaners are most often used on condenser coils where a heavy duty cleaning fluid is needed.

Alkaline Cleaners

Like acids these to are very effective cleaners. They are usually fairly safe and can be used on evaporator and condenser coils. They do not have the strong odours associated with acidic cleaners. Care must taken, however, as they may be caustic and so corrode organic material – safety instructions must be followed.

Solvents

These can be used where it is inconvenient or dangerous to use a cleaner that causes a lot of wetting; they dry quickly and need limited rinsing. They are also effective at removing grease from coils in kitchen environments. Again care must be taken with these cleaners as they can give off strong fumes. They must be used in well-ventilated areas.

Detergent or Foaming Cleaners

These cleaners contain either surfactants or detergent, to speed up the cleaning process. They tend to be alkaline. They are effective at removing grease and tar build ups but are not so good at removing heavy dirt. They are a good general purpose cleaner; they tend to be fairly safe and are often biodegradable. They will require rinsing.

Disinfectants

These will kill microbes. As discussed in the previous article an evaporator coil often is a breeding ground for a large number of microbes; these can give unpleasant odours and cause health problems for the building occupants. An evaporator coil will need cleaning and disinfecting. A standard cleaner will not kill all of the microbes.

Disinfectants for evaporators can often be bought combined with a cleaner. This allows the cleaning and disinfecting to be done in one application rather than two, thus saving time.

A disinfectant will not prevent future microbe growth; it will only kill those that are present on the coil or in the drain pan at the time. As soon as the HVAC system is turned back on after cleaning microbe growth will start again and any unpleasant odours will reappear. Where smells are a problem, often referred to as “Dirty Socks” or “Tom Cat” syndrome these are best dealt with using a product, which will ensure that the coil stays clean.

For example, Advanced Engineering Limited manufacturers a product; the StayClean Treatment Pack, a thorough, initial cleaning of the evaporator is carried out using a pre-cleaner/disinfectant. Once clean and dry, a coating of StayClean is applied to all surfaces of the coil, the drain pan and end coils. The product forms a microscopically thin coating that will work over a period of time to dramatically reduce the numbers of microbes attaching themselves to the evaporator surfaces. When correctly applied the StayClean treatment will prevent any microbial re-growth for a period of many months.

The added benefit is that the evaporator will also stay clean for longer. The final part of the treatment is to add a StayClean Strip to the drip tray, this will provide water activated, time released control of microbial contamination in the tray.

Cleaning coils as part of a preventative maintenance programme is essential for the clean running of any AC&R system. Not only to prevent damage to the coil, but also to maintain optimum operating conditions and to retard microbial growth.

Advanced Engineering Limited manufacturer a complete range of cleaners suitable for the majority of applications and are recognised experts in the field.

For more information please contact:

Advanced Engineering Ltd,
Guardian House,
Stroudley Road,
Basingstoke,
Hants,
RG24 8NL,
UK.
Tel: +44 (0) 1256 460300
Fax: +44 (0)1256 462266.
Email: sales@advancedengineering.co.uk