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Infrared heating diagnosis


A stand-alone IR camera provides better images, but some people find an IR attachment for their smartphone is adequate for their needs.

By Roy Collver

I have been on a career-long search for nifty tools that will help us all be better at the job of designing, building, commissioning and troubleshooting everything hydronic. There have been a number of breakthroughs over the years, and I intend to address them all sooner or later. Big game-changers in the last three decades have had mostly to do with developments in the electronics world. The shortlist includes:

  • Electronic combustion analyzers and gas detectors
  • Personal computers and related software
  • Digital troubleshooting equipment (multi-meters, data loggers, thermometers & pressure gauges)
  • Digital electronic controls
  • Digital cameras
  • Smartphones and tablets
  • The Internet

Digital infrared cameras, the newest kids on the block, have been around since the early 1990s when they graduated from primarily military and law enforcement devices to become available for civil uses. They were prohibitively expensive until a decade ago when companies like Fluke and Flir brought affordable (but still pricey) models to market – designed for general trades and maintenance users.

This photo showed a very high 70-plus degrees Delta-T between supply and return, pointing to a serious problem. It was quickly determined that tubing lengths in the slab were twice that specified in the design.

New players have emerged with a wide variety of models, and prices for base models have plummeted. Also known as thermographic cameras or thermal imaging cameras – they can make images based on longer than visible light radiation. If you want to impress your friends at the next party, you can explain to them that visible light is in the 400 to 700-nanometer range, whereas infrared cameras can detect and image wavelengths as long as 1,400 nm (14µm).

Seeing the heat

Why am I so impressed with these tools?

You can now achieve what hydronicians have dreamt about since we started moving hot water and steam through pipes.

DHW at the faucet is only 100F, showing that adjustments need to be made to the DHW recirculation system in this building.

You can see the heat!

This is a big deal, not only because it frees you up from running around to look at a dozen different thermometer readings – but because it can give you an overview of the whole heat transfer process at a glance. This is a powerful thing. Just look at the thermographic images included in this article and imagine how these cameras can help you be better at what you do.

They don’t have to be used just for fluid heat imaging either. You can look for heat loss through insulation in building assemblies, ductwork, piping – you name it.

An infrared image shows that the three-way tempering valve designed to prevent cold return water from getting back to the boiler is performing as required.

I use one extensively during engineering site inspections. Want to know if a branch duct is connected and working? Turn up the thermostat and point your camera at the diffuser to see if any heat is coming out. Take a picture to document it. Is the fluid flow going in the right direction? Look at the temperature drop or rise with your handy-dandy IR sensor. Most of the rest of this article is going to tell the story through images I have captured on job sites.

You will notice immediately that the resolution of my IR images is not very high. The units I used for this article both had a resolution of 320 x 240 pixels per inch whereas the Nikon digital camera I usually use for taking magazine photos has a resolution of 4608 x 3456 ppi. For most users of IR cameras, the lower resolutions are just fine, since the information we are after does not require photographic detail. Be prepared to spend far more for even a small increase in resolution.

Low cost entry

The camera I use on a regular basis is a tiny little thing that I plug into my iPhone – brilliant technology at a very reasonable price. A number of manufacturers make similar devices and the lower price point is simply because your phone does all of the heavy lifting as far as displaying, processing and storing the images – the camera itself just has the imager and lens.

The only issue I have with mine, and ones like it, is that they are fragile, small, and easily damaged. If you are very careful, they will stand up to the day-to-day rough and tumble of a service technician, but there are more robust models made specifically for harsh service conditions. Be prepared to pay extra for them, but if I was back in the service business, I would gladly pay the extra (engineering weenies like I am now have a far gentler life).

Roy’s cat Oscar can see in the dark. With an infrared camera, so can you!

Where can you get these things? Surprise, surprise – try your local plumbing and HVAC wholesaler; they likely have them in stock or can get them in a day or two. Before you make the jump, see if you can borrow or rent one to try out. Read through the specifications and user instructions of various manufacturers and models to see what appeals to you – talk to factory reps., go to trade shows, and do your research. I said the prices of these cameras has really come down – I didn’t say they were cheap.

A powerful sales tool

Keep in mind that although these are great tools for diagnosing problems and documenting system operation, they can also be a very powerful sales tool. If you show a building owner a thermographic image of a boiler with collapsed refractory, for instance, they are going to ask you to fix it immediately because the boiler will look like it is about to melt – not really too far from the truth actually.

HVAC technicians can use them to look for duct leakage, examine condenser and evaporator coils, electric motors, electrical connections and relay contacts – the list is long. Once you start playing with these devices, all kinds of uses pop into your head.

And if you are a hunter? Come deer season, some models will allow you to see where the deer are even in the fog, heavy bush or in low light conditions. Hiking here on Vancouver Island or the Alberta foothills – you can use them to scan your back-track for stalking cougars – just sayin’.


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