View Full Version : Predictive Maintenance

30-08-2003, 07:50 AM

Vibration Analysis, Ultrasonics and Thermographic Emaging.

What are your comments on this stuff when it comes to our HVACR business?


Can we leverage on these stuff to make an edge against competion and are they effective?

Thanks to everyone for your comments and ideas.

30-08-2003, 10:32 AM
Personally, it all sounds like someone trying to make make money for testing things just because.
Surely most engineers can see what sort of state a system is in by looking at it without the need for all this expensive equipment.
However would like to hear frfom anyone who has had these done & picked up a fault, i doubt these will become common practice though.

03-09-2003, 09:30 AM
One application of Thermographic Imaging is thermoscanning old coldrooms for heat leaks. There is an energy saving potential to this and this could be a selling point.

Otherwise, these equipment are too expensive - very low ROI

03-09-2003, 10:35 AM
Clients have been known to carry out vibration analysis, but the most common thing is eddy current analysis of the tubes in water / refrigerant heat exchangers. This is a definite must do, if you want to avoid water in your fridge circuit without just replacing the heat exchanger wholesale (very expensive!)

04-09-2003, 08:57 PM
Vibration analysis can be quite effective when used for monitoring of motors or bearing surfaces. Can you honestly say that that compressor motor that has been running for ?? years sounds normal ?

Also, if used for noise transmission problems in buildings due to mechanical noise you can identify the source and then remedy it.

A few years back we employed a noise/sound specialist and a vibration analyst at a sound recording studio where the ground floor studio was suffering from some low frequency noises. The equipment identified to noise which was a worn bearing on the A/C ventilation fan mounted on the roof four floors above the studio.

Vibration equip. then tracked it down to a worn shaft bearing, two worn out anti-vibration mounts and the fan being slightly out of balance.

So yes, there is a use; yes, it can be expensive; yes, the results can pay off; but.... agree costs with the client before engaging any specialists and their boxes of tricks.

19-03-2004, 03:57 PM
as a thermographic engineer , i have to say that you really need to see it to believe it. thermography is in no doubt the way to provide a maintenance programme that all will understand...... best thing to do is check this web site out.


19-03-2004, 05:19 PM
Originally posted by davidler
as a thermographic engineer , i have to say that you really need to see it to believe it. thermography is in no doubt the way to provide a maintenance programme that all will understand...... best thing to do is check this web site out.


How can you with your Flir see a faulty pressostat?
Used it amany times but not always usefull.

19-03-2004, 07:12 PM
hi peter,

the thermographic system is good for fault finding in electric cupboards, it detects the heat in the contacts and find those that have excessive temp.

expensive service, I use a laser thermometer, not bad, if you do it slow, you get over 95% of faulty and too hot contacts before anything goes wrong.

of course its useless on pressostats, and other refrigeration and AC controlls because of the low currants.


19-03-2004, 08:16 PM
Agree completely Chemi but my reaction was more because I saw it as a hidden advertisement.

We used it it in the past on air curtains to adjust the lovers, airc urtains at the entrance of a freezer, to prove that some wall counters (what's the name for this in English?) lost more cold then the otherswe compared Linde, Chief and Tasselli) , searched fo underground leaks, .. but all this is no predictive maintenance.

You can indeed find losen screws in switch-cupboard with it but that's almost all for our job (regarding preventive maintenance)

I also use an infrared thermometer (small one, not a camera) for this and one of the things we do is measure some 'critical' temperatures (suction, discharge, liquid in out condensor), mark them with a marker and we smeasure then eacht time the same spot when doing maintenance.
You have then some kind of history of temperatures but if this is usefull???? Especially when you do it only 3 to 4 times in a year.

19-03-2004, 08:34 PM
ofcourse its an advertisment and not hidden.

when you post what you do, what it it does and your web site, I call it "going fishing"

people are doing it all the time, as long asits not too much, I dont mind.

oh peter, I wanted to tell you, just bout anew two sensors thermometer that shows, T1, T2 and T1-T2, very comfortable for adjusting TEV's.


22-03-2004, 02:02 PM

It was only meant to comment on the use of thermography,

Laser guns are ok for small panels, its just a little daunting when you are doing a suite of probably 40 panels where the camera is more useful and quicker.

its also very dificult to pick up a loose connection or a rogue crimp with a gun.

Where theres a problem there is always heat, or extreme cold if you have a leak.



22-03-2004, 03:06 PM
hi david,

no problem with that at all,

thermography is good tool, no doubt, but the cost can scare away some good poeple.

if it was not so expensive, I would use it more often.

we do not check 40 panels at on go, but usualy, its the panel at the place where we work.

working with a gun is ok and I get better with time, I KNOW where to look for the problems and if there are any, they are always there.

chemi :)

22-03-2004, 05:30 PM
OK Guys, Let cut to the chase,
While i appreciate that you should use a thermograph on coldrooms etc and the costs are large, exactly how large either to get sombody in OR to buy the eqipment



24-03-2004, 04:22 PM
ok the costs are from 375.00 to a max of 450.00 per day this includes a full color report of any faults found .

thats a lot cheaper than a blown up contactor that has dmaged the whole panel or even caused a panel fire... not to say the food lost in the fridge or freezer.

i don't think in todays world that this is an excessive cost due to the fact that the camera to buy would be 30,000