Repair or replace?
The answer isn't always simple
Air conditioning has become such a major part of our home and work lives that when systems break down we demand that they be fixed immediately. But when this happens, The customer needs to make a serious decision about whether to replace their equipment or repair it, especially when older plant is involved.
Often, the first instinct is to call for a quick repair job. But is this the right decision? Repairs on an existing unit may be the least expensive short term option. Installing a new, energy efficient system may be a better long term option, both in terms of performance and operational cost.
Every scenario is different. Deciding whether to repair or replace requires balancing a range of factors, of which cost, may not be the most important. So how do you decide?
There are many pitfalls in replacing an old air conditioning system, it’s not just a matter of pulling an old one out and installing a new one. If you look at a typical split ducted unit that has failed and is 10 years old you need to be very mindful of the following: the old system probably operates on the refrigerant HCFC 22 (R22) and contains mineral oil in the system; while the system’s interconnecting refrigerant pipework is only rated for R22 - a medium pressure refrigerant. When replacing an R22 system these days - particularly with many air conditioner manufacturers offering high pressure refrigerant HFC410a (R410a) - the interconnecting refrigerant pipework will not be suitably rated for R410a. The minimum refrigerant tube wall thickness for R410a is 0.81mm, requiring a complete piping change. To highlight this point if you took an R22 system it’s pressure would be 1940 kPa and an R410a system would be 3045kPa at 50C saturation Pressure (abs), a big difference in pressure that reinforces the point about using or not reusing the correct rated pipe. With operating pressures some 50-60% higher than R22 you need to know what you’re doing.
Due to size, location and cost, it may impractical to replace the unit. As we mentioned previously many older systems contained mineral oils and nowadays the replacement compressors use a POE (Polyol Ester). So if an older system has a compressor failure great care is required to ensure that the old mineral oil is removed from the system prior to the installation of the new replacement compressor with POE oil, as the two oils are not compatible. This incompatibility will create problems to the system causing the oil to deteriorate or enabling sludge to form, leading to clogging of expansion devices and compressor failure.
Temperzone Sales Engineer James Demetriou says that one of the key issue concerning replacement equipment today is the increased physical size of modern units. “What’s becoming more of a problem with the ‘new breed’ is that they’ve had to grow in physical size to accommodate larger fans which operate more efficiently at lower rotational speeds,” he says. “Because of the MEPS (Minimum Energy Performance Standard) compliance, energy consumption must be reduced and performance improved, which is a major challenge for manufacturers.”
The MEPS programs are made mandatory in Australia by state government legislation and regulations which give force to the relevant Australian Standards. Regulations specify the general requirements for MEPS for appliances, including offences and penalties for non-compliance. Technical requirements for MEPS are set out in the relevant appliance standard, which is referenced in state regulations. State-based legislation is necessary because the Australian constitution gives states clear responsibility for resource management issues, including energy.
It is mandatory for products manufactured in or imported into Australia to meet the MEPS levels specified in the relevant Australian Standards, which has made a real impact on the energy efficiency of the new breed of air conditioners.
If you look at an older R22 split ducted unit manufactured prior to MEPS it would have had an EER (Energy Efficiency Rating) of 2.4 compared to the new MEPS requirements of 2.75 for the same unit. The new units are about 10% more efficient but come at the cost of being physically larger.
To answer to the repair or replace question several important factors need to be addressed, including:
• Availability of replacement parts;
• Age of the equipment;
• Condition of the equipment;
• How long will the air conditioner be down while awaiting repair?
• Labour resources;
• Energy efficiency; and
• Owner’s budget
In general, the more efficient the unit, the more it will cost initially. However, more efficient equipment will actually save you money over time as it requires less fuel to cool your home or business, especially with a 10% increase in efficiency due to the MEPS requirements.
There is also a proven link between effective maintenance and energy efficiency – properly maintained plant and equipment consume less energy, as well as being better for the environment, safer to operate and cheaper to run.
The AIRAH Handbook talks about the economic life for air conditioning equipment ranging from a split unit at seven years to a large package unit at 15 years. Many air conditioner manufacturers only carry parts for units up to seven years of age and after that a generic replacement part needs to be found, and in some cases modified, to fit the system.
Temperzone is one of the few manufacturers in Australia that still carries parts for systems more than 20 years old.
In many cases if the equipment is over 10 years old then the likelihood of genuine parts availability is reduced and the system is probably costing money in energy.
There’s no simple answer to the repair or replace question but our recommendation would be to discuss all the options with your service/maintenance provider; get all the facts and then make your decision. One thing that is definitely required to ensure a long lifespan and an energy efficient air conditioning system is good regular maintenance. You wouldn’t drive your car for 10 years without having it serviced; and to get the best performance out of an air conditioning system, it needs to be treated with the same tender loving care.
Temperzone sales offices and our free call technical support line can assist contractors, service companies and consulting engineers to gather all the correct information needed to make a final decision when it comes to replacing or repairing your air conditioning system.
