Evaporating TemperatureI have been amazed and depressed by the antimold articles recently published in The News, where the advice has been to correctly size the equipment to ensure adequate running time.
Gary Lloyd’s article (“To Remove More Moisture, Lower Airflow Speed,” May 19) was a breath of fresh (dry) air. He correctly points out that some manufacturers have secured high efficiencies by designing their units to run at coil temperatures that are too high for best dehumidification. He is the first in a long line to correctly advise that the route to dehumidification is sufficiently low coil temperature. Also, he explains how to measure the effective “coil temperature” in a coil that is dehumidifying by measuring the wet-bulb temperature of the air leaving the evaporator coil. (Lloyd called this the “supply air.”)
However, when there is no dehumidification, then the “coil temperature” cannot be measured that way. Then it will be necessary to measure the evaporating temperature either by measuring the actual pressure at the suction connection of the evaporator and looking up the temperature corresponding to this pressure or, if the system is sealed, by locating a thermocouple on an intermediate coil return bend.
Then, if the evaporating temperature is too high to secure the desired humidification, the airflow should be reduced. It is always a good idea to check the suction pressure and look up the corresponding evaporating temperature when servicing a system. This will help guard against coil freezeup and low refrigerant charge also.
Dan Kramer, P.E., Yardley, Pa.
It Takes Training And ExperienceCome on, guys, and give us a break. Everyone hates callbacks as much as the next guy does. We, as techs, get tired of people who do not have a clue about what we do in the field telling us how to do a better job. Many times you go on a call and the problem is intermittent or in the customer’s head or you make a repair on a unit that needs to be in a trash can or they are selling the house tomorrow or some other B.S.
Then you hear people quoted in your article state that if their people have callbacks, they fire them. Here in our area, we have people run ads for weeks at a time and not even get a hit.
It all comes back to giving the techs the best training, training materials, and training on the job. The only way to get the time and experience on the job is to do the job. The only way to get techs with five to 10 years’ experience is to grow them or steal them. Due to a shortage of good techs, so many guys are just thrown out to the wolves just so someone can show up on the job. Even with the best training you can get, there are so many ways to do the same thing between manufacturers. There are so many tech issues with a lot of the newer equipment that if you do not regularly sell or service that line of equipment, you are in the dark.
Basic schooling at best is very generic and basic and then you have to get into the field and get up to date on your line of equipment. This is a very high-tech and rapidly changing field. If you work on other brands of equipment you do not ordinarily handle, you can make mistakes and bad calls and not even realize it. In few other fields do you have a tech that is expected to work on so many different types of equipment on a daily basis.
I do not mean to harp, but get off of the guys’ and gals’ backs. By the way, I am NATE certified in four areas and working on trying to get them all.
John W. Walker, Service Tech, Hudson Heating and A/C, Middletown, Ohio
Publication date: 06/02/2003