“The ease of use and the camera are gold”

Published 2022-08-10

Almost ten years ago, Johannes Öberg switched from being a shop salesman to a service technician in ventilation. He hasn’t regretted it for a second. We caught up with Johannes to talk about the varied challenges of the job, ‘airborne’ and his love of testo 400.

– I like this job because no two days are the same. “There are always different conditions and challenges that must be solved to ensure good ventilation and a comfortable indoor climate,” says Johannes Öberg, who is currently a ventilation technician at Bravida.

An example of this is when Johannes and his colleagues were hired to review the ventilation system of a tire company. The unit was old, but even old units can last for many years. If they are maintained at regular intervals, that is. This unit had received minimal love over the past eight years.

“The air did not get through”
– One of the fans tripped because of the overheating protection and we had to do an extensive cleaning and filter replacement. They were so dirty that the filter bags had started to come off the frame. The air was simply not getting through. ‘It was like trying to draw air through a plywood sheet,’ Johannes recalls and continues:

– Of course, it took some time to fix everything. And time, as we all know, is money. But the people working there have to have air and that unit hadn’t delivered any air for years. It had just stood and walked with a single working fan.

This is what Johannes likes about his job. He enjoys tackling something that is a bit tricky, thinking about it a few times and then coming up with a solution. It is far from easy all the time, because every site is different. From belt-driven fan systems from the early 1970s to the very latest advanced ventilation systems with different layers of control systems.

Factors affecting air quality
Johannes and his colleagues are often called out on emergency missions. Often the complaint is that it is too hot in a room. While it may be that the ventilation system is not doing its job, it is remarkably often the case that other factors affect the perceived air quality.

– One room may have been converted into a conference room and more people are staying there than before, which affects the air. It can also be about a light source that makes the room warm. Sometimes it’s a bit difficult to determine whether it’s hot air or stuffy air. If it’s just stuffy air, it often means that we have to fix the ventilation. But if it is too hot, it is more likely to be due to the cooling or heating system.

A common ‘air villain’ is dust. Air ducts that have not been cleaned for a long time can accumulate up to one centimeter of dust, which reduces the diameter of the pipes quite significantly. This creates annoying additional noise and also results in lower air flows.

“The pipes are roaring”
When we meet Johannes, he and his colleagues are busy finishing the rebuilding of the ventilation system in the roofing company Wicote’s premises in Arendal, just outside Gothenburg.

It is a relatively old facility that has looked the same for many years, even though the premises have been redesigned several times to suit different tenants. The challenge was to find a good ventilation solution without rebuilding everything. There is nothing wrong with the unit and the airflow is there. Instead, it has involved, for example, adding supply air ducts where necessary.

– There is noise in the pipes, which is a sign that the unit is running too hard and pushing out too much air. During the adjustment, we will open all the valves fully and measure the total flow.

– By adding up all the sub-flows, we know that it should be a total of 330 liters. We put the aggregate at about ten percent above that to have a bit more to work with. We will then go around measuring and adjusting the devices, and then turn down the fans if necessary.

You use testo 400 exclusively, why?
– For several years I have used almost exclusively Testo instruments. This is largely because several other manufacturers have designs and user interfaces that feel very dated.

– One thing I like about the testo 400, for example, is when measuring with hot wire in a channel. The graph then guides me through the measurement. “If I set up twelve measuring points, for example, the meter tells me to insert the probe nine millimeters into this borehole, it then registers the result and I can move on to the next measuring point,” says Johannes, who points to the instrument’s large touch screen and then adds:

– The 400 is also particularly good if you are measuring a duct that has a touch screen. Then you just hold the hot wire sensor against the cover to measure.

Easy for everyone to use
Johannes points out several times that he appreciates the simplicity of the testo 400. Since he uses the instrument daily, he has quickly learned how it works. But it works just as well if a colleague needs to borrow it to measure the flow in a channel, for example.

– We have compared and seen that it works without problems. I have first made a measurement, handed the instrument to a colleague who made his own measurement and then compared the results. Especially hot wire measurement is very sensitive, because if you tilt the sensor towards the air stream a little bit, you get a completely different value. But by being guided through the measurement, both I and my colleagues got the same results.

– The instrument is a great help for those who are reasonably experienced and fantastic for those who are less experienced.

Create and send reports
The instrument’s built-in camera and report function is something that Johannes really likes and uses a lot.

– It’s great to be able to create detailed, attractive reports directly in the tool and then email them to customers. With the built-in camera, I can take pictures that show, for example, the position of the damper during the measurement. It shows which sensor was used and the differential pressure and airflow.

In addition to attaching pictures, there is the possibility for Johannes to easily enter text explaining what he has done, thus avoiding discussions about the number of working hours and costs for e.g. service with filter replacement. Johannes Öberg believes that it is this simplicity and all the smart functions that make the testo 400 an extraordinary measuring instrument.