Air Conditioning Repair… Old School vs New Tool

If “A man whose only tool is a hammer tends to treat everything like a nail,” then what happens on an air conditioning service call… when a technician’s only performance diagnostic tool is a set of refrigerant gauges?

Too many technicians think their gauges are the only tool they have or need to find out if an HVAC system is operating correctly when performing air conditioning service.  And those technicians are just wrong.  Refrigerant gauges were made to put refrigerant into systems and to take refrigerant out.  They can also be used to help calculate superheat and subcooling. Refrigerant gauges only monitor a  single conditional variable in the  operation of a cooling system. Air conditioning service should include much more than just a quick look at a systems refrigerant charge.

Refrigerant gauges  don’t tell a technician very much about a systems operating performance when performing air conditioning service… for one very simple reason …they were never designed to.

Refrigerant gauges became the … go-to performance diagnostic tool …

by default … not by design.

 Here are a few things that refrigerant gauges can’t tell a technician:

When performing air conditioning service, refrigerant gauges  can’t  tell a technician how many BTU’s a system is producing or what SEER ( at what cost)  those BTU’s are being produced.

When performing air conditioning service, refrigerant gauges  can’t  tell a technician if the supply ducts are crushed so badly … or are so undersized that the system isn’t moving enough air.  And their gauges can’t tell them if the system is sucking in 140 attic air because there is a massive hole in the return air plenum or that the ducts static pressure is above  … the fan’s static capacity.


When performing air conditioning service, refrigerant gauges  can’t  tell a technician if there is a dirty evaporator coil problem.  Every technician and his helper has an opinion about when an evaporator is too dirty and when it isn’t … But neither of them have the necessary facts to make an informed decision about how dirty is too dirty … Let an evaporator get dirty enough and those refrigerant gauges may help … or they might just fool a technician into thinking your system is undercharged.


Then there’s the same problem with the dirty blower.  When is it too dirty?  Here’s another dilemma technicians face when performing  air conditions service.  What if the evaporator is not visibly dirty enough to pull and clean and the blower does not appear to be dirty enough … but their combined condition is having a serious downward effect on your systems  performance?

What if everything is OK except the blower speed?  How far off does that have to be before it shows up on a set of gauges as something other than an over charge or an under charge?

As remarkable a tool as they are, even the refrigerant gauge can’t be used for everything when performing air conditioning service.   We could… but we won’t… go into a discussion of how “proper refrigerant charge” is dependent on outdoor ambient conditions, indoor air flow, and indoor humidity and temperature.

And if these reasons aren’t enough to motivate contractors,technicians, and home owners to give up using the wrong tool for the right job when performing air conditioning service… there  is an even better  reason to stop using refrigerant gauges for something they were never intended to do.


  Using Total Performance Diagnostics is almost too easy…

1. We  gather three temperature readings.

2. We  input those readings into our web based Total Performance Diagnostic program.

3. If the system report is within an acceptable range of operation … you know the air flow is within range … you know the refrigerant charge is OK… we know the metering device, compressor, condensing coil, evaporator coil and blower are all OK.  (see Diagnostic Brain Cloud)

4. If the system report is outside an acceptable range of operation … you know there is a problem that needs fixed … and the technician can spend your money identifying real problems, making real repairs and not charging  for time spent… CHASING GHOSTS.

 Home owners keep living with expensive poorly operating air conditions systems when technicians can’t identify system performance problems during routine air conditioning service calls.