Intermediate Maintenance Practices

SKU: RVI-11514Duration: 20 Minutes

Can you differentiate between an inner race and an outer race? What is Delta T? Heating and cooling systems require preventive maintenance to run efficiently. All motors and heat transfer equipment need to be kept clean, and bearings need to be properly lubricated. This interactive online course covers some common techniques for maintaining motors and electrical contacts, bearings, chillers, coils, and steam traps.

Course Details

Specs

Training Time: 20 minutes

Compatibility: Desktop, Tablet, Phone

Based on: Industry Standards and Best Practices

Languages: English

Learning Objectives

  • Demonstrate common maintenance techniques
  • Understand medium-to-advanced lubrication practices
  • Define terms related to heating and cooling maintenance
  • Identify problems related to a lack of routine maintenance

Key Questions

The following key questions are answered in this module:

What are common causes of motor failure?
Premature bearing failures due to poor lubrication is one of the most common causes of motor failures. Common lubrication errors include using the wrong grease, contamination, insufficient grease, and over-greasing.

What is the purpose of a chiller?
Air conditioning systems for larger buildings use chillers. A chiller is a refrigeration unit designed to produce chilled water for cooling purposes. There are air-cooled chillers, which use air for condenser cooling, and water cooled chillers, which use water.

What are some common causes of poor heat transfer?
Some common causes of a poor heat transfer are fouled tubes, non-condensable contaminants in the refrigerant, low refrigerant charge, bacterial growth in the water, and other cooling tower problems.

What methods are used to clean coils?
Coils can be cleaned with compressed air or with water and cleaning solutions depending on the amount of buildup. For difficult deposits, a pressure washer that is specifically meant for cleaning coils can be used at the recommended pressure.

What is the purpose of electrical contactors?
A contactor is a large relay, or switch, that supplies power to a load, such as an HVAC fan motor. A contactor consists of a coil that creates a magnetic field when energized. This magnetic field pulls the contacts closed, applying power to the load.

Sample Video Transcript

Below is a transcript of the video sample provided for this module:

Rotating elements, such as motor shafts or axles, rely on bearings to provide support with minimal friction. Ball bearings are the typical bearings used for HVAC applications because they enable high rotational speeds with minimal friction due to their small contact area. A ball bearing consists of spherical balls held in place by a cage, between an inner race (ring) and an outer race. The inner race is the part of a bearing that makes contact with a shaft and rotates. The outer race is usually stationary. Both races are grooved to provide a path for the balls. The ball bearings transfer the load between the inner and outer races. The cage keeps the balls in place, which reduces friction and provides a uniform distribution of the load. The lubricant, typically grease, is packed in the spaces between the races and the balls. Some bearings have metal shields or rubber seals to retain lubricant and prevent particle contamination. A shield is a metal ring that is pressed onto the outer race, but it does not touch the inner race. Sealed bearings use rubber seals that can be contact or non-contact. Obviously, bearings with contact seals provide the best protection against contamination and leakage. Premature bearing failures due to poor lubrication is one of the most common causes of motor failures. Common lubrication errors include using the wrong grease, contamination, insufficient grease, and over-greasing. Following bearing manufacturers recommendations for proper lubricant and lubrication frequency will keep the motor running trouble-free. A common mistake made by maintenance technicians is using the wrong lubricant and applying it incorrectly. Sealed bearings are lifetime lubricated, so there is no need to add grease.
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