Somebody please explain this to me

[bobb25]

These are interesting posts. I don't do refg., just res / light commercial HVAC. Truck is loaded with parts mostly, so don't have a lot of room. 2 large nitrogens, gauges, scale, leak detectors, digi-clamp on, thermometers, etc.

Best tool I have is my ears. Listen to the customer for 5 minutes and ask them questions. Even if the customer doesn't know what's wrong, you should be able to narrow down the problem. Start out with basic dumb questions, like does it do it all the time, when was the last time it worked right, does everyone else in the building think it isn't working right, etc. Listen and process the info, and then ask more specific questions. You should have a good idea where to start looking before you ever pull out a tool.

[300sdturbo]

There are some really interesting threads in here. If I picked up a couple of pointers (like layered ice on a coil), I guess it just shows my age. There is wisdom in both agruements, not to change the subject,the young'uns could do with a little better manners...

[Executioner]

I will never downtalk another tech. from mine or another company regarding their diagnostic practices to a boss or customer unless their work or practices are just abhoherent.

Everyone learns differently and applies what they learn differently, some need the facts and figures, some can go by expirience and just about diagnose the problem while walking and talking to the customer to the unitin question.

The best suggestion to new tech's is while your taking your reading's touch and feel the refrigeration system,listen to it..the compressor and the general noise of the unit.

BEST ADVICE! Enjoy what your doing! take the good with the bad, but in all I REALLY enjoy walking in to a restaurant that has a Walk In down and saving the day.
Not soo much the creeps that don't appreciate your effort and think a pizza is comensurate compensation for 4 pounds of R22 and 2 hours labor.

But hey..... it's a living

[icehouse]

I to can diagnose whith my senses, but back everything up with proper readings.
In a lawsuit situation the Judge will throw you out unless you have proper documentation. Case in point when I serviced for Trump Management we had a woman who swore while she was at work at night, the Super sent someone to turn off her refrigerator causing her food to spoil. I installed a recording Amprobe and presented the documentation in court as she was suing for loss of food and to deduct this from her rent.
After seeing the recorded information the Judge threw the case and her out of court.

[Frostie]

I agree with Executioner, our senses are our best tools.

[TEK723]

Alot of diagnostic's can be done without ever putting guages on a system.

For instance: WI freezer coil iced up, you proceed to put it in defrost,heaters heating, grab amp probe, drawing proper amps, ok get the mapp gas torch and melt alittle of the ice and find layered ice, ie..clear/frosty/clear/frosty ect...
Conclusion: once coil is defrosted and provided box comes down to temp. properly you need more defrost's or time on defrost. only if ice buildup is even top to bottom on coil.
If it's all white frost then too much humidity entering box.
Guages ARE needed to diagnose a sytem IF needed, some weeks I go 2 or 3 days without even getting them out the truck, while correctly diagnosing iced up coils not cooling and bad compressors that are electrically fine, coast's to a stop after 3 or more seconds and drawing low run amps, shaft is sheared compressors toast. Shut off comp. and suction line immediatly gets hot, high side valves are shot.
Walk up to the unit and box is slightly up in temp. coil has light frost at end with compressor iced around suction area= overfeeding TVX or overcharged.


Everyone has their own method of diagnosing a system, No one method is perfect. It is all based on that individual's expierence,preference,training.
I was taught in the field and have no clue how to calculate subcooling. Never needed it.
No clue how to calculate loads but recognize when a new store calls in on a 90 F day and the dinning area is pushing 80 F , on the roof you got 1 or 2 small A/C's and heat is pouring out the fans, If I got 20F temp. difference between return and supply air well gee I guess somebody saved a few bucks on xtra cooling.
Since 1988 I can safely say......
I'm not perfect and don't know it all and am still learning new thing's, but I'm comfortable walking into any refrigeration problem, wether it's new or after several other tech's have looked at unit with a few call back's. I always tell the customer that you'll know exactly what's wrong with the unit before I leave, and I'll either have it repaired or know what I need with no excuses.

WOW

[shallowluv]

There are A LOT of diagnostics that can be performed w/out meters and gauges. Some can not. I work on ice machines in several major restaurant chains and they like documentation of performance and certain repair procedures. Also, if you are blowing a control fuse due to a short how would you determine it's location? The first part of this statement is only partially correct. You could have a faulty defrost termination sensor bringing the unit out intermittently causing ice build up. Tools are only there for you if you know how to use them. Wonder how many units have been replaced that you have repaired. Without the readings that are taken with tools performance can not be reliably confirmed. To save the day today and cost a compressor later because of , lets say a high discharge temp that you did not take, is completely unprofessional. We require readings for post repair performance and we have virtually no call back issue at all. 3 call backs for 6 techs so far this year. Over 4000 units repaired or installed so far this year. I consider us to be a very small company. We also have very little turnover. 4 techs with over 6 years and me with 4. We work long hours and without readings and doc. the info could be easily lost

[TEK723]

WOW

I responded to the wrong thread shallowluv, sorry! still learning the site.

[green jumper]

I may be able to do some initial diagnostic without gauges or tools to take measurements in some cases. But I sure wouldnt leave the job after the equipment is working without taking those readings.