ACHRNEWS

Ice Breaker: The Visual Inspection

November 7, 2011
A refrigeration technician’s job can be broken down into three different areas:

1. He must identify the cause of the problem;

2. He must repair the problem; and

3. Throughout the process, he must serve as a customer service representative for his company.

In many aspects the first part of a job is like detective work — not only does a technician need to identify the problem but he also must determine its root cause. A good initial step is to visually inspect the entire system. Before taking any measurements or recording any information, the technician should inspect the system and look for any obvious problems or clues that will help determine the cause of the failure.

Follow these tips as part of your complete inspection:

• Although an obvious point, check what is running and, more importantly, what is not running. Be cautious of remote air-cooled condenser fans — during low outdoor temperatures some of the fans may not be running or running at a reduced speed. This could be its normal operation; however, if it is above 70˚F outside you would expect most all of the fans to be running.

• Check the condition of the evaporator coil. Is it iced over or dirty? How is its airflow? Is it restricted or being recirculated?

• Check the condition of the condenser coil. For air-cooled condensers: Is the coil dirty? How is its airflow? Is it restricted or being recirculated? For water cooled condensers: Is water being supplied to the coil? Is the water-supply sufficient? (This might be difficult to determine by a simple visual inspection.)

• Inspect the refrigerant piping, looking for damaged or oily locations.

• Inspect the electrical panel and associated wiring for any damaged or broken wires.

• Don’t forget hardware issues such as hinges, door gaskets, door closures, etc. Problems with the door and its hardware can lead to excessive air infiltration into the case.

• Determine the type of refrigerant and metering device used on the system. Also determine the type of control system and, if applicable, the type of defrost controls. This information will be helpful once you start inspecting the system’s operational parameters.

Here’s an example:

You are called out to troubleshoot why a walk-in freezer’s temperature is at 30˚F. You arrive on the job and, after speaking with the customer and before taking any readings, you look over the system. You inspect all of the items listed above and you notice the compressor is cycling off and on repeatedly. Upon further inspection, you find the discharge line and its surrounding area are oil stained. This leads you to suspect the system has a refrigerant leak and that the leak is somewhere in or around the discharge line.

You attach your refrigerant and temperature gauges to confirm your initial suspicions of a system low on its refrigerant charge and then begin leak searching the system to find a leak on the discharge line.

Great — a relatively easy problem to identify and repair. But what caused the leak? With a little more inspecting, you notice the pipe clamp holding the discharge line is very loose and its rubber insert is missing. With time and vibration, the clamp easily damages the pipe and causes the leak. So after repairing the pipe, you also replace the clamp and properly secure the pipe preventing a future leak from occurring.

A thorough visual inspection can be a tremendous aid while troubleshooting and repairing any refrigeration system. It should be performed each and every time a technician works on a system.

Publication date: 11/07/2011