Tag: troubleshooting

This article is part 5 of a 5 part series on troubleshooting by Senior Refrigeration and HVAC tech Jeremy Smith

This might be the most challenging part of troubleshooting. We’ve got a “Most Likely candidate” for the trouble, but we don’t know for certain that’s what is wrong.

 

So, we have to combine our customer skills, our experience, and our troubleshooting skills.
Let’s correct that “Most likely” problem that we’ve identified. Clean a dirty evaporator or
condenser coil, replace the plugged filter drier, repair the leak and recharge the unit to
specifications…

You’re done, right?

Not so fast…

This is where things can get interesting. Looking at our flowchart, we’ve got a decision loop
here. Make the repair or correction to system operation, then reevaluate system performance. In
reality, this puts us back to the gathering data phase of the process, but we don’t have to
Necessarily gather the same data twice. If we replaced an air filter or a belt or we cleaned a
coil or replaced a capacitor, we can ignore that on our second (and maybe
subsequent) evaluations.

We’re now looking at system performance. Most manufacturers publish methods to evaluate
their systems. If those fail, we can always resort back to the ‘rules of thumb’ and check to see if
our system operations data now falls into line with accepted industry norms.
If the unit doesn’t match up with manufacturers specifications or industry standards after making
the initial repair, continue the data gathering, data evaluation and repairing the next most likely
problem the data points to.

Be very careful here not to focus on a single aspect of the system. Let’s say you had a high-pressure
trip due to a dirty condenser. So, you clean that coil and reset the pressure switch.
Don’t key in exclusively on the high side readings and miss a low superheat issue. Monitor
ALL of the system conditions and only when everything is within industry norms (or the
customer refuses the work, of course) do you move to the final part of the flowchart and
terminate the troubleshooting process.

 

Now go out and fix some stuff right the first time.

— Jeremy

This article is part 4 of a 5 part series on troubleshooting by Senior Refrigeration and HVAC tech Jeremy Smith

Ok, so we’ve got our data scribbled and scratched out on paper. Maybe a bit of grease, dirt and oil, too, if you’re doing things right and blood if you’re doing it wrong.

 

Now, time to take a short break and congratulate ourselves on doing it right while sitting and thinking. Have a coffee and look over your data. Now you have some decisions to make.

 

Much has already been published on analyzing data on a refrigeration system, so I don’t think I need to reinvent the wheel here and review various combinations of pressures, superheat and subcooling and airflows. If you haven’t yet internalized this information, don’t be afraid to have a nice laminated copy of the printout on your truck until you do.

 

The thing to remember here is that the more data you have and the more accurate that data is, the easier troubleshooting will be for you.

 

As an example, if you’ve got a unit with a TEV running a 10° subcooling and your low side shows a lower than expected suction pressure and superheat, do you have an airflow problem, a low load problem or a sizing issue? Without collecting good data, it can be difficult to distinguish between the problems but, if you’ve taken TESP readings, return and supply dry and wet bulb temps and have the unit model/serial info on hand when you sit down to analyze the data, the problem should be more apparent.

 

Evaluate the patterns in the data. Look broadly at all the data and see the patterns. If you have a good data set and a good understanding of the operation of this equipment, a “Most Likely” candidate for the problem is going to emerge.

The final step is coming tomorrow.

— Jeremy

 

This article is the second in a 5 part series by Senior refrigeration and HVAC tech Jeremy Smith 


The Ground rules

I’ve spent some time thinking about troubleshooting and the processes and procedures that
I use to find problems. Not the “why isn’t my air-conditioner running?” problems but the “Things
just aren’t quite right.” type problems. The really difficult ones.
I’ve boiled it down to a sort of flowchart to simplify things and we’ll take the flowchart
step-by-step, explaining each step as we go along.
Something to keep in mind as you read this. There is no step by step, color by numbers guide
to troubleshooting. I’m not trying to give you a magic wand to wave at broken air conditioners
because such a thing doesn’t exist. Troubleshooting is more of a “can do” attitude combined
with experience and some applied critical thinking.
First thing, let’s start with a couple of “Dont’s” when troubleshooting.

#1. Don’t rush

Yes, I know that many of us get piled up under a load of calls and can
be pressured to rush through them to get home to the family. Yes, I know the boss or dispatcher (or both) are calling
you every 10 minutes asking if you’re done and ready to move. Yea, I know the customer is
breathing down your neck to get the machine running. This is probably the hardest part of
troubleshooting. You NEED TO block that stuff out. You need to take your time and work
through the problem methodically.
#2. Don’t assume

Follow your troubleshooting procedure through to the end. Taking
shortcuts is almost as bad as allowing yourself to be distracted.
Over the course of a couple of articles, I’m going to share my troubleshooting processes and
procedures and hopefully give you some tips to build a process that will help you to be better.

Part 3 is coming tomorrow

— Jeremy

 

Tunnel Vision and How To Avoid It

How many times has this happened to you: You’re on your way to that final service call. While you’re listening to the customer explain their complaints over the phone, there’s this precise moment where you’ve thought: “I know what it is already. This will be a quick one.”

Sometimes intuition proves to be a useful tool for an efficient service technician, but that same intuition can bite back fiercely if it leads to ignoring the whole picture.

Let’s take a simple example. The customer reports that their unit isn’t cooling very well and it seems like it’s running longer than normal. The immediate thought may be that the refrigerant charge is low. Reading the pressures on site, it’s discovered that the unit has lost most of its charge. While it can be tempting to restore the refrigerant charge, find the leak, and write up the repair to keep moving, it’s vital to evaluate the rest of the system before proceeding.

Failing this can lead to upset customers who, after paying for the initial service, can face the prospect of additional repairs. Here are a few simple steps to avoid this pitfall:

  1. Listen closely to the primary complaint and address this problem first.

  2. Take care to note any contributing factors to the primary complaint. Ask yourself questions like: “What caused this problem in the first place? Could this happen again if these conditions persist?”

  3. Watch out for any other potential failure points unrelated to the primary complaint.

  4. Document all findings in detail and take the time to explain why each concern is valuable to your customer.

Taking these few extra minutes on the initial visit can save you and your customer precious time and frustration. Resisting the temptation to only solve the first problem will often lead to a more fruitful service call. Nothing beats the peace of mind that comes with a thorough diagnosis.

– Zach S.

This article was written by Senior Refrigeration Tech Jeremy Smith. Before we get to it I want to remind you that ALL of the tech tips are available in alphabetical order HERE – it’s a great link to share with other techs, HVAC business owners, Trade school students etc… you can feel free to share these anywhere.


Alright, maybe “advanced” isn’t the right thing to call this little tidbit, maybe it should be “troubleshooting and information sharing in the digital age….”

Microprocessor controls, PCBS, PLCs, call them what you will, electronic circuit boards have become an integral part of the HVAC/R world. From a small heat pump defrost board to an advanced building automation system, these little pieces of equipment seem to be the bane of a techs existence.

One very important thing to remember when working on a system with one of these items installed is that each one has a specific troubleshooting procedure and its own sequence of operations.

So, how is a tech supposed to remember all of this stuff?

Pro Tip.

You DON’T.

Chances are good that you’re reading this on a smartphone or a tablet. With that and a couple of free apps, you can build a library of tech manuals, reference documents and other information to allow you to be better at diagnosing problems on specific equipment.

 

So, how do we build this? Well, you can go Old School and print out all of the manuals and store them in your service truck, or we can keep up with the times and go HVAC/R School and put it in “The Cloud”.

 

Everybody has a Gmail account. Maybe it’s your primary email, maybe it’s the one you give people that you don’t really like so you never hear from them again. Well, with every Gmail.

account comes 15GB of free online storage through an app called Google Drive. Grab the Google Drive app from the app store or play store and, if your Gmail is logged in to that phone, the drive app is already logged in to access your cloud storage. Now, start to “build” your reference library by uploading those PDF files to the drive.

Sometimes this is easier to do on a PC, but it can be done from a phone or tablet as well, it’s just a bit more tedious, at least for me. Then, the next time you’re on a job and have to search and find a manual for a piece of equipment you’re working on, save it to your Google Drive, too. Before long, you’ll have a very
nice library to draw from.

If you’re feeling particularly generous, within Google Drive, you can share that information with co-workers and other techs. You can either allow them to contribute to the library or just to view
it.

You know what’s better than having a good memory? having good resources. Oh and reading… you pretty much can’t be a good tech nowadays if you never read.

Sorry…

— Jeremy

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