At www.achrnews.com, The NEWS’ Extra Edition page is home to hundreds of online-exclusive service and maintenance, technical, and business management articles. Here are some of the best.
QUICK FACTS: MIGRATION AND PUMP DOWN SYSTEMS
Migration is the term used to describe when refrigerant moves some place in the system where it is not supposed to be, such as when liquid migrates to the compressor sump. This phenomenon occurs because refrigerant will always migrate to the coldest part of a system. A pump-down system consists of a normally closed solenoid valve installed in the liquid line and a low-pressure control that senses suction pressure. It prevents liquid from migrating to the compressor crankcase during the off cycle.
BTU BUDDY 30: REPAIRING A RESTRICTED LIQUID LINE
The dispatcher has called Bob with a no-cooling service call. Actually, the unit had been cooling until last night when the home began to get warm inside. Bob arrived and talked to the homeowner about the situation. He then went to the outside unit and found it was running, but the suction line was frozen back to the compressor. He decided there must be restricted airflow or the system was low on refrigerant. After checking for a refrigerant leak, Bob discovered a kink in the liquid line.
PRESSURIZATION OF CLOSED HYDRONIC SYSTEMS
Most modern hydronic heating and/or cooling systems are closed systems that must be maintained at some minimum pressure. This would seem to be a simple concept, but it is surprising how often a lack of attention to the basics can cause all kinds of problems. System pressurization is a concept that is often misunderstood and overlooked as the source of problems in closed systems. As with most other aspects of hydronics, pay attention to the basics, and you will have more success.
THE UNDER-MANAGEMENT EPIDEMIC
There has been so much talk about the engagement of workers: Are your employees engaged or not? But that’s the wrong question. The key factor affecting employee engagement is the relationship employees have with their immediate supervisors. Therefore, the question you should be asking is this: Are your managers engaged or not? From our ongoing research, we have become convinced that too many of those in leadership positions are disengaged from their direct reports on a day-to-day basis.
Publication date: 9/12/2016
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