Inverter driven air conditioning is more energy efficient, cheaper to operate and more profitable to install than its non-inverter driven equivalent. Here Neil Ballinger, head of EMEA at automation parts supplier EU Automation, explains how HVAC engineers can maintain the inverters in their customer’s aircon units.

Do you remember cross country at school? It was exhausting; miles of seemingly pointless jogging and sprinting and, if the teacher was not looking, walking. If you were unlucky enough to be born before modern safeguarding measures were introduced, it probably also meant getting lost in the nearest woods.Why isn’t every installation an inverter driven unit, instead of the traditional single stage or dual stage models?

My PE teacher, who seemed particularly vicious at the time, but in retrospect just knew about sports science than most, used to make us do something called fartlek as well. This meant long distance runs, incorporating elements of speed training by mixing up sprints with jogs and walks.

The worst bit was starting to run again after a walk. That is exactly how the motor in your customer’s air conditioner feel if the units you fit are not inverter controlled. The motor has to act just like a runner doing fartlek — it sprints continuously, operating at full speed until the thermostat tells it the room is cool, then it stops. When the room gets warm, it starts again, powers immediately up to full speed and repeats the process indefinitely.

Just like a teenage cross-country runner, it is the starting and stopping that is the tough bit. Furthermore, the unit probably doesn’t have to run at full speed to keep the room at the correct temperature, if the motor were inverter controlled it would speed up and slow down as the temperature fluctuates.

Why isn’t all aircon inverter driven?

We all know that inverter driven aircon is better than its non-inverter driven cousins. It can provide heating as well as cooling and the lifetime cost of use is less for the customer — because their energy bills stay low. The cost of installation is also higher because it is a more complex job, so it works out better for the contractor. It’s a win-win.

The research firm Technavio even lists it as one of the key technologies driving growth in the HVAC market in its annual reports every year. So, the only question is, why isn’t every installation an inverter driven unit, instead of the traditional single stage or dual stage models?When contractors contact EU Automation to buy automation parts, for the units they maintain, they have given us another reason: maintenance

Cost is a factor, but when contractors contact EU Automation to buy replacement motors and inverters, and other automation parts, for the units they maintain, they have given us another reason: maintenance.

As HVAC engineers, we are not necessarily specialists in power electronics, and this makes inverter maintenance daunting. Microcontrollers and IGBTs (Insulated Gate Bipolar Transistors) are not beyond us by any means, but they can be intimidating. Personally, I would back an electrical or heating engineer over an electronics specialist in a problem-solving contest all day long; but that doesn’t solve the problem at hand.

Furthermore, while we are experts in air conditioning brands, and know our Daikins and Grees from our Mitsubishis and Fujitsus, we don’t necessarily have contacts at the inverter manufacturers. Amtech, Danfoss, Vacon and Yaskawa are all names we know, but the local dealer for any of them is probably not in your phone book. This is especially true if the unit you need is from a first-generation inverter driven aircon unit and well over a decade old.

While we are experts in air conditioning brands, and know our Daikins and Grees from our Mitsubishis and Fujitsus, we don’t necessarily have contacts at the inverter manufacturers

Maintenance techniques

While inverter maintenance can be daunting, it isn’t difficult. The tools you will need most often are nothing more than a rag and a spanner, while the more esoteric kit is stuff you probably carry anyway, a laptop, vacuum and a Fluke meter.

Before you start, remember that while we tend to refer to an inverter as an inverter, the manufacturers themselves, and many of the sources of information online, often refer to them as VSDs (Variable Speed Drives), VFDs (Variable Frequency Drives) or just plain old drives.

As a result, when you are searching online for a video to explain something, it’s worth using all three of those terms, alongside the inverter manufacturer’s name and the problem to make sure you get the right result.While inverter maintenance can be daunting, it isn’t difficult

When you do move on to maintenance, step one is simple; make sure that the unit is free of dust. This is as easy as vacuuming the heatsink with an ESD (Electrostatic Discharge) vacuum cleaner when you perform routine maintenance or investigate a problem.

While you are checking for build up of dust and daily grime, check the filters. They will probably have to be replaced during annual maintenance, but high use might mean they need to be replaced more often.

The control panel itself should be well ventilated and free of dust as well, if it isn’t it can overheat, which is the number one cause of inverter damage and the most common reason contractors contact us for replacement units.

Before you put your vacuum and duster away, you should make sure that the inverter unit’s location is clean and as sheltered from the elements as possible. Because it’s normally situated on a roof, it’s not going to be perfect, but the units are designed to take a limited battering. That doesn’t mean it’s okay for them to be covered in leaves, surrounded by rubbish or immediately beneath the guttering outlet though!

Before you put your vacuum and duster away, you should make sure that the inverter unit’s location is clean and as sheltered from the elements as possible

Get out the spanner

Once you’ve finished these steps, you are done with dusting for now, it’s time to get out your screwdriver and your spanner.

Step one is to make sure the fans on the inverter are operating normally, without noise and with nothing blocking their rotation. The fan keeps the internal components running effectively, just as it does on PC, and if its function is impaired the capacitors will overheat and the inverter will fail.When you install or maintain an inverter on an air conditioning system, it is a sensible precaution to back up the drive parameters to your laptop

The next job is to grab your spanner and make sure the power terminals are on tight. Loose connections cause arcing, overheating and even melting of components and are easily checked during any kind of maintenance and repair.

While we are still in the realms of the work your apprentice can do with their eyes closed, you should also make sure that the inverter’s removable LCD control pad is stored sensibly and not continually attached to the drive. If it remains attached, there is a chance the display will stay on permanently, which means that when you need it to diagnose a problem, it will probably already be burnt out.

Break out the laptop

When you install or maintain an inverter on an air conditioning system, it is a sensible precaution to back up the drive parameters to your laptop. It takes minutes and is normally done by using the removable LCD control. In fact, it’s often as simple as selecting ‘PARs’ and then ‘BACKUP’ from the menu. If you struggle, there are lots of videos on YouTube, like this one, which explain the process for each drive.

As a result, if the inverter ever does need replacing, you can whip out your backed up parameters and order a new or refurbished one easily, before reloading the parameters to the replacement and getting up and running in no time. Your customers will think you are a power electronics genius, as well as a HVAC expert, and they will be loyal for life; especially of you save them on a hot day!

If you follow these simple measures, you will find that the inverters in your customer’s air conditioning units last much longer and no motors will have to run the equivalent of a cross country, thanks to a lack of inverter control.

Share with LinkedIn Share with Twitter Share with Facebook Share with Facebook
Download PDF version Download PDF version

Author profile

Neil Ballinger Head of EMEA, EU Automation

Neil Ballinger is head of EMEA at automation parts supplier EU Automation and regularly contributes to the company’s knowledge hub, where the business originates content ranging from bestselling books about automation to insights from the leading minds in the engineering industry. EU Automation provides replacement parts, such as motors, drives and PLCs, for the HVAC sector, as well as others, across the globe.

In case you missed it

The Impact Of Millennials And Other HVAC Industry Trends
The Impact Of Millennials And Other HVAC Industry Trends

Millennials have been shaped by their experiences growing up with technology and by their heightened awareness of the environment. These facets of a consumer market dominated by millennials will guide the future of the HVAC market over the next several years. Each generation reshapes markets in their own image. In the case of millennials, trends and behaviors are influencing how companies design new solutions, including those in the world of HVAC. Sustainable solutions and personalized experiences Millennials place a premium on sustainable solutions that reduce their environmental impact Millennials place a premium on sustainable solutions that reduce their environmental impact. Millennials also want more personalized and convenient experiences, and they value enhanced customer service support. New systems designed with a personalized and ecological mindset are amplifying efficiency and convenience and giving unprecedented control to create a truly connected home for technophilic millennials. Future HVAC products to cater to millennials The challenges of catering to millennials is one of the trends LG Electronics has listed among those likely to impact the HVAC industry in the months and years ahead. The trends are directly guiding LG’s product mix, including WiFi-enabled indoor units and LG’s Smart ThinQ application, which put the ability to control a home’s comfort system at the consumer’s fingertips. Here are some other trends to watch, listed by LG Electronics, when looking ahead to 2021 and beyond: Greener solutions on the horizon: Beyond appealing to millennial sensitivities, green solutions have a long list of their own advantages. Industry providers are responding by creating more sustainable and efficient products to enable customers to reduce their carbon footprints. LG Inverter air conditioning systems are designed to minimize efficiency losses, provide sustainable energy savings and contribute to lower lifecycle costs. More efficiency and reduced costs: Geothermal heat pumps have quickly proven themselves to be an alternative energy source, offering both warming and cooling capabilities. They are a highly effective and renewable energy source that can transfer heat from the ground to cool and heat buildings. Minimizing greenhouse gas emissions: Connecting HVAC to the electrical grid highlights the importance of reducing greenhouse gas emissions. Air-to-water heat pumps and other solutions can generate cooling and heating from one unit, thus furthering the transition from natural gas, fuel oil or coal. Fulfilling the need for new employees: The next generation of HVAC engineers and technicians requires training programs. LG Air Conditioning Academies provide training and skills programs around the world to empower the new generation of HVAC professionals. The impact of COVID-19: The pandemic has created a need for greater safety precautions within the HVAC industry. Remote working trends and additional precautions will likely continue to impact the industry even post-pandemic. LG HVAC systems are evolving to better aid the road to recovery and to prepare for the new normal with optimal solutions for the ever-changing challenges.

Residential HVAC Continues to Show Business Strength Amid COVID-19
Residential HVAC Continues to Show Business Strength Amid COVID-19

The entire economy has been severely impacted by COVID-19, with small businesses being hit the worst. These businesses make up 47% of the private labor force and contribute 44% to GDP in the United States. Thankfully, not all small businesses are the same. Jobber’s Home Service Economic Report: Summer Edition analyzes the performance of the Home Service category throughout 2020, and shows a positive path towards recovery. It shows that the Contracting segment, which includes HVAC businesses, had its first full quarter of positive year-over-year growth since the start of the pandemic. As we look ahead to the future, it’s important to reflect on the past year and understand how residential HVAC, and the Home Service category as a whole, has fared through this pandemic and the economic turbulence that it has caused. Jobber’s report highlights some trends and key findings that can help guide companies through the end of the year and into 2021. The Residential HVAC Industry Falls within a Strong Home Service Category Wrapping up the third quarter, it’s clear that the Home Service category—including residential HVAC—continued to recover as the economy opened up and consumer demand rebounded. With the exception of Grocery Stores and General Merchandise Stores, Home Service was the most stable category through the peak of the pandemic. It also recovered very well through June and into Q3, showing 10% year-over-year growth in September, compared to other categories such as Clothing Stores and Restaurants, which registered declines of 12% and 14% respectively. New Work Scheduled Finds Pre-Pandemic Success New work being scheduled is an early inductor of the health of Home Service businesses, and a proxy for consumer demand. When the pandemic first hit, the Contracting segment, which consists of industries such as Construction, Plumbing, and HVAC, saw a sharp decline in new work scheduled in March and April. Residential HVAC continued to recover as the economy opened upAt its lowest point, Contracting saw new work decline by 23% year-over-year as states across the country began implementing stay-at-home directives and consumer spending tightened. This impacted revenues in April and May, where growth declined 15% year-over-year, roughly 25% below expectations. Despite this dip during the initial peak of the pandemic, new work scheduled for the Contracting segment started to show signs of recovery from May onwards, hitting a record high for the year in June with 15% growth year-over-year, and consistent positive growth since then. As a result, the third quarter revenues for this segment have also shown positive results. Although the growth was moderate earlier in the quarter, the Contracting segment finished strong with 12% year-over-year revenue growth in September, matching pre-pandemic levels. Employment Growth Sees Upward Trajectory In April, the U.S. unemployment rate shot up to a record high 14.7% largely due to COVID-19 layoffs, but improved to 10.2% in July as the economy began to reopen, and further to 7.9% by September. For Home Service specifically, the category began 2020 with positive employment growth in Q1 that outpaced the employment growth in Total Nonfarm. However, stay-at-home orders in April caused employment growth year-over-year in Home Service to drop drastically by 12.9%, although this was still a bit better than the 13.4% drop for Total Nonfarm employment. Since this drop, Home Service has seen rapid recovery, with September employment only showing a decline of 3.9% year-over-year while Total Nonfarm shows a decline of 6.4%. Digital Payments on the Rise Despite Historic Resistance The Contracting segment has historically been a bit slower to adopt digital payments as these businesses often have large invoice sizes, and don’t want to collect payment using methods that can deteriorate their margins. However, according to market reports, the adoption of digital payments has accelerated significantly due to the COVID-19 pandemic. The adoption of digital payments has accelerated significantly due to the COVID-19 pandemicSpecifically, the estimated percentage of transaction values done digitally in 2025 is now expected to be 67% rather than the previous estimate of 57%. In our data, we saw a significant increase from January to May, from 32% to 37%, in the share of payments being collected through digital methods, compared to other methods such as cash or check. While each business has its own unique dynamics related to e-payment usage, it will be interesting to monitor this trend heading into the new year, as social distancing continues, and more companies commit to improving their technology usage. Although there has been a positive economic turnaround for all categories towards the end of Q2 and through Q3, it’s difficult to predict where we are going with the recent rise in COVID-19 cases throughout the country. While consumer spending and employment have recovered from the massive declines they saw in early Q2, they seem to be stagnating a bit below their pre-COVID growth levels, suggesting that both consumers and businesses are remaining cautious. One thing is clear though, Home Service as a category is incredibly resilient as most businesses managed to survive through unprecedented economic hardship, while finding new and better ways to service their customers.

Could Thermic Heat-Generating Paint Play a Crucial Role in an HVAC System?
Could Thermic Heat-Generating Paint Play a Crucial Role in an HVAC System?

Is wall paint a feasible element in an HVAC system? That’s the supposition that underpins Thermic heat-generating paint, which is applied like conventional paint but then can heat up a room when it is connected to a safe level of 24 volts of electricity. The paint is a water-based, solvent-free and low-pollutant dispersion that provides a wafer-thin carbon specialty coating (about 0.4 mm), which can be connected to a low-current circuit to provide radiant heat. In effect, the product allows a house painter and/or an electrician to “install” a heating system. infrared heating panel “Thermic heat-generating paint can be processed particularly evenly and is so electrically conductive that a low voltage of 24 volts is sufficient to generate high outputs of up to 100 watts,” says Hans Schulte, Director of Thermic Coating Systems Ltd., based in Chester, United Kingdom. The low voltage is selected in accordance with the “toy safety directive,” so it is safe to touch. The coating can be applied to any wall, ceiling or floor and transform it, in effect, into an infrared heating panel, says the manufacturer. The company suggests the coating would be particularly useful for builders planning a low-energy house. One liter of Thermic Paint costs 149 Euros ($175). low energy requirement This requires technology that provides heat at short notice - at the time and place where it is needed" “In new buildings, the trend is toward intelligent heating solutions that flexibly cover the low energy requirement and adapt to the needs of the user,” says Schulte. “This requires technology that provides heat at short notice - at the time and place where it is needed." The responsiveness is an advantage when compared to heat pumps, which require a lead time of several hours to change the temperature in a room, says Schulte. The system is particularly useful for concrete surfaces, and normal walls made of brick or wood are sufficient. The combination of products also has an almost unlimited lifespan and does not require maintenance, says the manufacturer. The coating can be painted over with standard colors. Low energy use is another advantage, with Thermic Paint providing the highest infrared heat radiation at the lowest energy consumption, according to the company. wall coating system With an efficient layout and intelligent control, the wall coating system can save more than 50% of a required heat load. An area of one square meter can achieve a surface temperature of 118 degrees F, so a few such areas on walls or ceiling can provide a warm comfort level. In effect, 6 square meters of heating area would be needed to heat a 25 square meter (269 square foot) living room, according to Thermic Coating. The company’s website says they are amenable to “attractive opportunities for cooperation.” Transformers are used to supply electricity, transforming the mains voltage to the low operating voltage. Thermic Coatings sees use of large-sized infrared heaters on low temperature on walls and ceiling as the future. It is most efficient to locate the heat paint in the coldest parts of a room, says the company. The paint should cover an area as big as possible to ensure lowest energy consumption while still heating the room.