In the HVACR world, it is not impossible that the designers of a walk-in cooler/freezer to mistakenly chose the wrong FPI (fins per inch) selection for the application you are servicing. Here is a table to reference when you are looking at possible causes of an iced-up coil. With fin spacing too close, frost can easily bridge the gap and quickly reduce air flow through the evaporator.
The proper selection of fins per inch plays a role in maintaining proper humidity levels in the conditioned space as well. The bottom line is this: don’t always assume that the application engineer can’t make a mistake in the selection process. Always look at this factor when troubleshooting your HVACR evaporator problems.
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.
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.
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.
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.
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.
Rolling Meadows, Ill. (Dec. 14, 2017) – RSES is pleased to announce the addition of four additional HVACR training books to its online store. All four titles are published by ESCO Group and add to the ever-expanding library of materials RSES offers to help industry professionals excel at their jobs.
Sample sections of each manual are available in the Table of Contents tab in the description section at the online store. For more information or to order these items visit www.rses.org/store or call 800-297-5660. Please note, RSES Members will need to login to the website first in order to receive the appropriate member discount.
I would not know what to do if I didn’t have Evernote to use as a tool for our business. I am the Training Manager for a Commercial Refrigeration company specializing in supermarket refrigeration.
Our service team all have the mobile version on our Android devices. My wife and I both have a premium version to use on mobile as well as our Macs at home.
I share around 10 notebooks with the service techs that have a plethora of information that is crucial to our daily routines, such as passwords, charts, phone lists, store information for each site, remodel notes, etc. Every time I get an email about a particular remodel, I send it to a new notebook that I have created for that remodel store and share it with the tech who handles the daily operations there.
I keep a recurring note called “Monday” where I collect the items that our service team will review when we huddle on Monday mornings to prepare for the week. I keep the bulk of the information in other notebooks and then link it to a bulleted list that we review. Any time during the week that I come across some useful information or think of an issue that needs to be discussed, I just add it to the “Monday” list. It works pretty much flawless.
My wife likes the shared notebook that we share since she handles the finances and every time I use the debit/credit card, I quickly take a snapshot for our shared list so she can always stay on top of our finances.
Yes, Evernote is an essential part of my life and has been for over 4 years. Our company also benefits from the technology and all the service team loves it too.
Attached is a snapshot of my Evernote web with just a few of the many notebooks that I have with nearly 10,000 notes.