MIDDLE TN RSES TO HOST HVACR CONTROLS COURSE

Get ready Nashville for the much anticipated and most requested HVACR training experience.

Continue to monitor this website for information regarding registration for this seminar.


DANFOSS WINS PRODUCT OF THE YEAR AWARD AT 2018 AHR EXPO

Danfoss, the pioneer of oil-free, magnetic bearing, variable speed technology, was recognized with the prestigious Product of the Year award during the 2018 AHR Expo for its Danfoss Turbocor® TTH/TGH high-lift compressors. 

A GAME-CHANGING APP

I just can’t say enough about an app that has become an essential part of my life and the overall operation of our HVACR service team.

I am talking about EVERNOTE. It is one of the best ways to assemble, organize and present information that I have ever seen. Now you may be thinking that I am compensated for endorsing this product but you are wrong. I am compensated by using the product. I use it for training purposes as well. It has a great presentation mode that I use instead of powerpoint slides.

I use it many times per day. It is extremely useful when we have our weekly service huddle meeting.

Below is a screenshot sampling one of our huddle meeting frameworks.

You can easily hyperlink the topics to other notes that have been organized into specific Notebooks.

We also have the essential Notebooks shared with all the service techs. It is feature-rich and the beauty is that it syncs across just about all platforms.

An example list of our company shared Notebooks contain the following topics: Work Data, Parts Information, Site Information, Memos, Policies, Training, etc. In these Notebooks are contained over 500 notes and training presentations. It is easily searchable for specific notes inside these Notebooks.

As we go throughout the week and run across some useful topic to discuss or encounter a recurring issue, we add it to the list for “Monday” and we keep the team informed. It helps us to maintain a near-paperless approach to our day to day business practices. For all our larger digital files that contain operation manuals and other manufacturer information, we use Box, which contains over 12GB of technical information for our team to access.

My wife and I both have the premium version and use it for all our financial paperwork and household business. Click here to for a free trial of Evernote.

THE MOTOR SAVER-PHASE MONITOR

Model 250A is an auto ranging voltage monitor designed to protect 3-phase

motors regardless of size. It is used on 190-480VAC, 50 to 60 Hz motors to

protect the motors from damage caused by single phasing, low voltage,

phase reversal, voltage unbalance, and also high voltage. Added features

include the DPDT contacts that are used to perform two functions when

parameters are exceeded in addition to the standard adjustable restart delay.

 

TESTING AIR FLOW IN SUPERMARKET CASES

One of the ways to assure that a customer’s case is performing as it should is to test the airflow. One of the best ways to do this is with a test instrument that measures feet per minute as illustrated.

Be sure to measure the airflow at the case discharge air outlet as illustrated below:

The manufacturer recommends that the best time to measure the case airflow is during the warmest time during defrost as the case cycle is terminating.

Below is a manufacturers chart detailing an example of a case specifications including the case design average air flow. Without the proper air flow, the case temperature will not reach the desired set point and the product integrity will suffer.


HANDS-ON COMPRESSOR TRAINING AT MIDDLE TN RSES

Members and guests got to check a fractional hp compressor for good/bad windings at the June 2017 Regular Monthly Meeting at the Middle TN Chapter. Jayson Goff, CMS was the seminar leader and had just returned from a winning battle over Stage 4 cancer. By the way, the compressor was deemed terminally ill by Larry Lynn, CMS and Doug Drake, CM, due to bad terminals.  😀

Indoor Air Quality Begins Here

The final factor in evaluating the air distribution in a space is the comfort of the occupants. In general, a person is thermally comfortable when body heat loss equals body heat production. What most people call a “draft” is simply a slight movement of air that results in a local feeling of “coolness.” It has been determined that a velocity change of 15 ft/min has about the same effect on comfort as a 1°F of temperature change. KEEP READING BELOW…..

A typical room air distribution system with local air velocities of less than 40 to 80 ft/min will satisfy 80% of occupants. Localized air temperatures should be less than 2°F below the general room temperature. The temperature near the floor should be less than 4°F below that at about shoulder height. For heating, local air velocities generally are below 40 ft/min. For cooling, local air velocities should be between 40 and 80 ft/min.

EXCERPT FROM “THE TECHNICAL INSTITUTE MANUALS,” available from the ONLINE STORE AT RSES.ORG

Sheave Maintenance

Routine maintenance of blower sheaves should include a close examination of the alignment of the motor and blower sheaves. Proper belt tension is also important to maintain the life of the sheaves. Groove gauges are often provided by belt and sheave suppliers to test the sheave walls for wear to determine the need for replacement.

Another important item to check is the RPM’s of the blower to determine if it is within the range that was established during commissioning by test and balance personnel or startup technicians. Once the sheaves get a measurable amount of wear, it becomes increasingly difficult to provide the proper air delivery of the blower due to lost RPM’s.

THE SUCTION LINE ACCUMULATOR

A defective expansion valve, refrigerant overcharge, or extremely low load may permit liquid refrigerant to reach the compressor from the evaporator. Because liquids are not compressible, the pistons and valves can suffer damage from such “slugs” of liquid.

To prevent this, you can put a suction accumulator in the suction line between evaporator and compressor. Trapped oil may build up in the bottom of the accumulator after the refrigerant evaporates. Accumulators therefore have an oil return line leading from the bottom of the trap.

This figure shows a cross section of a typical suction-line accumulator. It has a U-tube for passage of refrigerant vapor back to the compressor. The metering port at the bottom of the tube allows oil to return back to the compressor. The metering port is small enough that any liquid refrigerant entering should be boiled off before it reaches the compressor. EXCERPT FROM THE” TECHNICAL INSTITUTE MANUALS “AVAILABLE AT THE ONLINE STORE AT RSES.ORG.

VIBRATION ELIMINATORS

Rigid connections at the compressor are prone to crack or break from vibration and stress. The cause may be discharge gas pulsation or compressor movement because of high torque.

There is a simple way to prevent line breakage from these causes. Install vibration eliminators in both the suction and discharge lines. They should be the same size as the lines. Install the vibration eliminators parallel with the drive shaft on the compressor. It should only be clamped on one end.

A typical vibration eliminator has rigid copper ends to connect to the compressor and the system. Between the ends is a length of flexible tubing. It is covered with woven brass or stainless steel mesh for strength.

EXCERPT FROM THE TECHNICAL INSTITUTE MANUALS AT THE ONLINE STORE OF RSES, THE HVACR TRAINING AUTHORITY.