Ir compressor pics?

Can anyone tell me the exact reason for these rings showing up on the compressor/condenser?

Wouldn’t it be a condenser coil malfunction of some sort?

Thanks in advance for any feedback!





It depends on the pattern of your coil layout and if your compressor was
was in the “on” or “off” mode (as this will affect the pattern). Is this a
heat pump or just an AC condensor? What time of year is it and what is
happening in the photo? Don’t forget that heat pumps go into defrost
in some conditions. Were you getting good temperature read outs at
the supply air and return? How did the freon lines feel? Was the system
working to it’s full potential? At first glance, your assumption of a coil
being clogged or malfunction sounds right, but that is not the only thing
to look at. Do these IR photos bear witness with your verification
of the other parts of the system?

Hey John,

Thanks for the reply. I actually had another compressor/condenser unit showing the same thing on Wednesday just before sending my camera to FLIR. These pictures are from a separate unit from the pictures in my first posting.

This particular unit had been running for a good part of the inspection given it was only 1 of the 2 working units for a 7400 sq-ft home.

During an inspection I usually turn the air conditioning unit on inside of the house and set the thermostat to about 68-70. I wait about 15 mins then check the outside unit(always while it’s running and only during summer months) with my infrared camera. I mainly look to see if the temperature of the refrigerant line is not showing freezing or warm temps and also check the temperature of the air output at the registers.

This unit shows the refrigerant line being within the normal operating temperature range but it didn’t seem to be putting out cold enough air at the registers. It also shows the temperature rings like the unit in my first posting.

I reported that I recommend the unit be serviced by a qualified HVAC technician due to the dirty coils and that I didn’t feel the unit was preforming at it’s maximum potential due to the air temperature it was providing.

Do you have any further thoughts on these rings? I only see rings on about 1/20 units and it’s usually always the large units. I believe the larger units are showing rings due to the condenser coils being more spaced out due to the larger size. Would you agree that’s a feasible assumption?







If you want a really good insight in to units you might want to try posting your question over at or The 2nd one gets a ton of traffic and these guys will be able to tell you what is going on. They will probably also want to know the make, manufacturer and model number of the unit if possible.


These pics were of a unit running on a hot summer day about 2 weeks ago. Everything about the unit and the air output seemed to be good. The freon lines were normal temps, the cold air output at the registers was really good, and all the normal operating controls checked good. I didn’t report any defects pertaining to the unit because had I not had an IR camera everything would have checked perfect.

It just made me wonder a bit when I was saw the temperature rings because it’s not something I usually see. The other concern was that the rings only appear at the top of the unit vs. being uniform from the top to the bottom like they appear on the other unit in this thread.

I believe I’ll do a little more research on these particular units and let you know what I find.







Dave Anderson may chime in later with some ideas. What imager do you have Brandon?

Thanks Jason.

I wasn’t aware of either of those sites. They look like they will be quite helpful.

Hey Dave,

I was using a FLIR B200 (200 x 150 resolution model). It takes great images but I’ve got a bigger the better mentality.

I just sent my camera back to FLIR yesterday because their providing me with an upgrade to a 320 x 240 resolution model which I’m unbelievably excited about.

Adding thermal imaging to my home inspection business has actually made it fun again. Thermal imaging has turned into a fun hobby just as much as a home inspection tool.

I continually see things I would never be able to see without the IR so it keeps things interesting.

The A/C unit in the above pictures is just down the road from me. Once I get my camera upgrade I’ll re-take pictures of the unit and post them for a comparison.