The following tips are inspired from a manuscript on safety. For some of you, it will be a review to refresh your memory about the importance of "safety first." For those of you starting out as technicians, it could keep you from serious injury - or worse - out in the field. The speed at which you sometimes feel you need to do a job may cause you to overlook your own safety. A good example is carrying your toolbox, refrigerant drums, and other material up a vertical ladder using one hand. This can be very dangerous and has caused some serious injuries. Always use a rope to pull up tools and materials. Any job that involves the movement of heavy equipment requires at least two persons to be present. Also, working alone on a roof, or in an empty building, should be avoided. If you have to work under these conditions, have someone check on you, in person or by cell phone, every hour. Don't take unnecessary chances. Make sure you wear nonskid shoes (not leather soles), particularly where oil or plastic granules may be present on the floor. Steel-tipped shoes are also recommended. A long-sleeved shirt can protect you from hot compressor discharge lines and pipes.
Don't wear loose clothing, such as unbuttoned sleeves or shirttails that hang out. Loose clothing can get caught in moving machinery, such as fans, compressor shafts, pulleys, etc., causing serious injury. For the same reason, if you have long hair, be sure to tuck it into a baseball cap for your own protection. Earrings, bracelets, and loose neck chains can also be hazardous. From the moment you start your vehicle, you could be driving a potential bomb if you allow cylinders of refrigerant and acetylene being carried in the back to roll around. First, secure all these tanks. Then, make sure all the valves are tightly closed.
A service company may purchase a large cylinder of refrigerant and recharge this refrigerant into smaller cylinders to save money. This is not only illegal, it is dangerous. An overcharged refrigerant cylinder could explode if left in a hot vehicle. Don't rely on the refrigerant cylinder rupture disc. When starting a compressor, it is recommended that you stand clear from the direct line of the compressor heads on a nonhermetic-type unit. Why? The piston valve plate clearance is measured in thousandths of an inch and is usually determined by the valve plate to compressor body gasket thickness. If you have ever run a compressor with the heads off at 1,725 rpm, the speed of the pistons creates a blur and this should be respected. It's rare, but compressor assembly errors have occurred. An object that remains above a piston cavity could result in disaster.
Disassembly of the compressor head, cover plates, and anything requiring bolt removal requires that you be careful. You must loosen the bolts and then gently pry the head, valve, or cover plate from its seat.
There is a very good reason for this procedure. There may be internal pressure within the system. Or, if the object being removed is heavy, it could slip and cause injury. The same procedure applies to flywheel or pulley removal. Make certain the object is loosened from its seat before fully removing the nuts or bolts. A common error made by service technicians is to turn off the wrong disconnect switch. Obviously, the higher the voltage, the more serious this situation can be. Always check the circuit you are about to work on with a voltmeter and be certain that the power is off. When you are working on a low-temperature walk-in cooler, it's probably summertime. Make sure you have a winter jacket, wool hat, and gloves in your vehicle for this type of job. Not all cold storage equipment provides a means of quickly exiting. I have seen telephones, buzzers, axes, and TV monitors placed within the freezer compartment.
Regardless of the protection, nothing matches someone standing directly outside the door in case of emergency. I have been locked in a "safe" freezer, and will never have it repeated. As you go from jobsite to jobsite, you may encounter a customer who will want you to break the rules in order to get their equipment up and running as soon as possible. In many cases, this will be someone who doesn't have a maintenance contract and waits until his unit fails. He will tell you that if any damage is caused, he will be responsible.
Don't believe it for a minute. There have been a number of lawsuits where the customer wins the case because the technician didn't follow the rules.
My motto is, "Take your time and do it right." If you work for a company that allows you to overlook good safety practices, I would consider working for another company.
John Schaub is president of Schaub Consulting, Medford, N.J. He has been involved in HVACR as a field engineer and company owner for more than 40 years. For more information, contact 609-654-2138 or visit www.chillers.com/schaub.htm.
Publication date: 03/08/2004