The old saying, “measure twice, cut once,” can definitely be applied to our trade. In that same vein, service technicians should also remember to “think twice, do once,” because there are many times that we can be our own worst enemy. Simple mistakes we make can lead to some serious issues for both us and our customers. Thinking before doing is the key to avoiding some of these costly mistakes.
When de-icing an evaporator coil, for example, think about the best way to handle the job without causing damage to the system. There are several ways to safely de-ice an evaporator, including using water, a heat gun, or simply de-energizing the compressor and leaving the evaporator fan running. Of course, never use an ice pick or a metal object to de-ice a coil. Although water is a good option, it may not always be the right choice. If there is no way to drain the water away, or if the water can cause damage to an electrical component, it becomes a poor option. A heat gun works well too, but if the heat will damage any plastic housing, any electrical wiring, or any other component, it also is not a good choice.
When drilling, always look carefully at what you are drilling into or through. One day, I was drilling through a floor joist to run an electrical line and did not look at the opposite side of the joist — and drilled right into a water line. Not a good day!
Working with older equipment involves working with older nuts, bolts, and flare nuts. When taking these items off and putting them back on, care should be taken not to force them as this could easily damage the threads. If the threads do not easily fit on by hand, find out why before taking a wrench to them. Once the threads are damaged, the piece will need to be replaced. This is especially important when working with the bolts on a compressor. If these bolts become damaged, you may be forced to change out the whole compressor to repair the problem.
When diagnosing a system problem, always look at the entire system. If you need to measure the system’s pressure, always measure both the high- and low-side pressure. Do not be a one gauge technician. Also always inspect the condition of the evaporator and condenser coil before determining a system problem based on an abnormal pressure reading. A dirty coil or iced evaporator will cause an abnormal operating pressure not caused by a lack of or an excessive amount of refrigerant.
If a voltage, amperage, temperature, or pressure measurement does not make sense, check your tool. A defective tool can cause you to spend a lot of excessive time looking for a problem that does not exist or lead you in the wrong direction as you try to determine the root cause of the problem. I generally carry two of my commonly used test tools, so I have a backup if I need it.
So remember to “think twice, do once,” and avoid making costly mistakes for you and your customers.