Wednesday, May 20, 2015

Rees Scholarship Deadline Approaching

I have mentioned the Rees Scholarship in the past. Now is the time to encourage deserving students to apply. Copied below is a letter from Misha Adams of AHRI explaining a bit about the scholarship and how to apply.

Our July 1 fall scholarship deadline is approaching quickly!
The Rees Scholarship Foundation has awarded nearly $335,000 to 195 students enrolled in HVACR programs nationwide since 2003 – and we would like to expand our reach.
The Clifford H. “Ted” Rees, Jr. Scholarship Foundation was established to assist with the recruitment and competency of future HVACR and water heating technicians by awarding up to $2,000 to qualified students enrolled in an accredited school. The Foundation awards motivated students with a genuine interest in the HVACR and water heating field, helping some of the most promising candidates to successfully enter the industry.
This year, the Rees Scholarship Foundation would like to award more scholarships than the 43 scholarships we provided last year, and we need your help.
We truly believe instructors and staff play an essential role in not only educating and motivating students, but assisting them in finding opportunities to help them complete their education successfully. The numbers support this: Over 70 percent of our past applicants learned about Rees from their instructors. With that in mind, we would like to provide you and/or your school’s HVACR department with resources about Rees you can give to your students. These include brochures, flyers, and posters for the classroom. 

Brochures and flyers are also available for download at

To learn more about the Rees Scholarship and the submission process, review our FAQ  at

Download an application at

Please encourage your students to apply!
Feel free to reach out to me directly as well should you or your students have any additional questions. Also, please feel free to forward this message to your HVAC department colleagues and/or related staff members.


Misha Adams
Rees Program Specialist
Air-Conditioning, Heating, and Refrigeration Institute
2111 Wilson Blvd, Suite 500
Arlington, VA 22201
Phone: 703-293-4839

Monday, May 18, 2015

Cleaning Condensate Lines

In the southeast, it is a given that the evaporator condensate line will get clogged with slime. The only questions are how long will it take and how messy will it be to clean up? What we often did in the past was to cut out the section of drain near the coil, blow out the drain line, and rebuild the drain with new PVC ells and pipe. However, that means the owner is constantly paying for you to rebuild something that should be cleanable. That is why every evaporator condensate line should have a way to open the drain to facilitate cleaning. In fact, this is now required in the most mechanical codes. You can add cleanout spots by replacing ells with tees, or by using a manufactured product made just for that purpose. Rectorseal and MSD Research both market drain cleanout devices which make complying with the mechanical code and cleaning the drain easier. Ideally, you should be able to clean out the line in both directions – from your cleanout to the evaporator and from your cleanout to the outside.

A Gallo gun using CO2 charges works well for blowing out the drain line. Nitrogen does a good job too, but getting a nitrogen cylinder to the cleanout spot can be difficult. Another option is a sludge sucker. It uses nitrogen to create a vortex, which sucks the condensate and goo out of the drain line. The sludge sucker typically connects to the drain outlet. Some techs use wet vacs and connect to the drain outlet, or to points on the condensate cleanout. Even if the drain is not stopped up, clearing the evaporator condensate line should be part of normal service. Don’t make the customer call you back later because the condensate line plugged up.

Sunday, May 10, 2015

Pot Use Cuts Career Short

There is lot of press these days about marijuana becoming more widely accepted. However, you should be aware that marijuana use can have a very negative impact on your career. Employers can legally refuse to hire people who test positive for marijuana use. Many employers require drug tests for prospective employees, some use random drug tests on current employees. Since these tests can detect marijuana in your system for up to a month after using it, you basically need to not use it – even on your own time. I am writing about this topic because it has recently cut short the career of a promising student. He graduated and got a job in the field working with a good company. He was excited to get the job, and the company was happy to have him. He seemed to be working out – everyone was happy. Then he failed the drug test. End of job. The student really needed the job. The company was disappointed because they needed the help. However, they can’t afford to keep him. Their insurance won’t allow it. This is not just about someone’s idea of morals or right and wrong, it is about common sense. People who are not in full command of all their mental faculties should not be working around high voltages, driving, using torches, or any number of other potentially dangerous things air conditioning techs must do. There may be some companies that are OK with drug use – generally speaking these are not good places to work. First, they know you can’t get a job elsewhere, so the pay is low. Second, do you really want to work in a potentially dangerous field around a bunch of people who may not be fully conscious? Even if you don’t blow yourself up while you are high, the guy next to you might. If you want a full, productive career – stay clean.

Saturday, May 2, 2015

Mission HVAC

Shuretape has launched an initiative to follow three students at Athens Technical College through their studies in the Air Conditioning Technology Program. To support the students, Shurtape is challenging them each to a series of missions. They complete the mission and report their findings on the Shurtape blog. They have chosen three students with different backgrounds and different ages: Matt Morris, Daniel Buth, and Josue Treo. By following these three students’ blog postings, you can gain some perspective on what it is like to be an HVAC student preparing to enter this profession. They receive a new mission every month. The best way to find out more about these three outstanding students and their mission is look at the Shurtape blog

Friday, April 24, 2015

Keeping Your Cool!

Hot weather is coming, and that can mean slow refrigerant recovery. It is common to have high recovery tank temperatures and pressures shut you down as the temperature rises. The condensing temperature of the refrigerant in the recovery unit has to be higher than the outside temperature, and so the refrigerant leaving the recovery unit can be hot, especially on a hot day. This raises the recovery cylinder temperature and pressure, which in turn makes the pressure leaving the recovery unit climb even higher since it must be higher than the cylinder pressure. You often need to cool the recovery cylinder to keep going. There is the old stand-by: ice and a bucket. It works great, but involves the extra bother of carrying ice and a large bucket to the job site. You can use the recovery machine to cool off the cylinder.

Connect the vapor valve of the cylinder to the inlet of the recovery unit and the liquid valve of the recovery cylinder to the outlet of the recovery cylinder. Purge both hoses of air. Start the recovery unit with both cylinder valves open. After the unit gets started, turn the liquid valve on the recovery cylinder clockwise to create a restriction. Be careful NOT to completely close it off. You have just made a refrigeration system with the refrigerant recovery cylinder acting like a flooded evaporator.

The recovery unit is provides the compressor and condenser, and the partially closed liquid valve on the cylinder acts like a metering device. Liquid in the cylinder boils as vapor leaves, cooling off the remaining liquid. The returning liquid is at a lower pressure and temperature, thanks to heat being removed by the recovery unit and the pressure drop at the liquid valve. It takes a bit of practice to learn where to set the liquid valve, but you can monitor the two pressures on the gauges of the recovery unit. You should see both pressures drop as the unit operates.

I have made cylinders frost on the bottom using this technique. One caveat – if you wait until the high pressure switch on the recovery unit opens, you can’t use this method to cool the cylinder down since the recovery unit won't run at that point. You need to make sure and cool the cylinder before that happens. One manufacturer used to make a recovery unit with this feature built in. You connected two lines from the recovery unit to the cylinder, and anytime you needed to cool the cylinder down you would just set the recovery unit valves to subcool. This kept you from having to move your hose connections after the cylinder was cooled down. However, I don’t think it is available any more.

Saturday, April 18, 2015

Tape is Tape NOT!

I must admit that when Glenn Walter of Shurtape offered to do a presentation on duct tape application for my class I thought “Oh HOW exciting!” (Yawn) After all, how much can there be to know about duct tape? It can’t even connect to the internet! But then I really hate to turn away help and I like having people from the industry come talk to my students, so we set up a class. One thing I have come to understand about life in general: whenever I think there is nothing to know about a particular subject, it is only because I know so little I don’t understand how ignorant I truly am. When Glen started his presentation I quickly realized that there is whole lot to know about duct tape. What follows is a cliff notes version.

Duct tape consists of a backing and an adhesive joined together. There are four types of backing: cloth (the old standard), film, foil, and foil-skrim-kraft (FSK).  There are two large categories of adhesives: acrylic and rubber based. Most techs know that codes require UL 181 tape. However, did you know that there are two general categories of UL 181 tape: 181-AP and 181-FX.  AP is rated for use on rigid ductboard and FX is rated for use with flex. Note that there is no specific UL rating for tape on metal duct systems – UL 181 is for ducts made out of manufactured materials. You may have also seen tape with a UL 723 rating, which is a smoke and flame spread standard. It makes a difference WHICH UL rating your tape has. Just because you see UL does NOT necessarily mean your tape is correct for the job. Even two tapes with the same UL rating can have different application specifics. Also note that the UL rating is not based on the backing or adhesive, but the tape performance in specific tests. Shurtape has 181-FX tapes with foil, film, and cloth backing with both acrylic and rubber adhesive. They are all approved for use with flex duct, but each has a specific application where it is better. For example Shurtape’s film backed tape with acrylic adhesive is rated for application between -20°F and 220°F. Their other FX rated tapes won’t stick at -20°F.

Most codes now require mastic for sealing metal ducts, but many people still use tape underneath the mastic. Did you know that many duct tapes are not rated for that use? Mastic does not stick well to film tapes. Not all cloth tapes play well with mastic because the chemicals in the mastic and the chemicals in the tape adhesive may not be compatible. The cloth tape might turn loose, then having the tape underneath the mastic just creates a place where mastic is not fully adhered to the duct. Foil tape usually does fine under mastic.  You should check with the tape manufacturer before using a tape underneath mastic.

Finally, the tape application is not complete until you apply pressure. For foil backed tapes, a plastic tool with a stiff rounded edge is preferable for working the tape into the duct. The pressure is needed to fully activate the adhesive on the tape. The adhesive undergoes a chemical process, similar to glue setting. Duct tape is not fully adhered until this process has been started through pressure application and completed with time. Believe me, there is a LOT to know about duct tape. If you would like to learn more, contact Glenn Walter of Shurtape at

Saturday, April 11, 2015

Bluetooth Tools for HVAC

At the recent HVAC Excellence Instructor’s Conference there were many digital tools featuring Bluetooth connectivity on display. These tools allow you to use phone and tablet apps which take readings from the device as input. This can be as simple as just displaying a reading, or more helpful such as using the reading to perform a calculation. Most also allow the user to use their phone or tablet to send the information to someone else. Technicians can send real time readings to a service manager for consultations or document results to verify system operation. Most of the devices were measuring pressure and temperature. Of course, the Stride i-manifold was there. It was actually introduced last year. This year they have company. Fieldpiece has had wireless gauges longer than anyone else, but they used a proprietary signal. This year Fieldpiece was showing a set of digital gauges with Bluetooth and a Bluetooth wireless bridge to allow their older Fieldpiece wireless gauges to connect to Bluetooth.

 Yellow Jacket, Appion, and Sporlan all had pressure and temperature measurement tools which featured Bluetooth connectivity and apps designed to work with the tools. To be sure these are not manifolds, but pressure and temperature measurement tools. Appion had a trio of pressure gauges and a Vacuum gauge. Their gauges each have a digital display as well as sending Bluetooth information to your phone. They are “short” gauges with a short stem, allowing connection without filling a set of hoses with refrigerant. The Yellow Jacket Mantooth device is also a “short” gauge, but it has no display. Like the i-manifold, it relies on your phone or tablet for a display. The Mantooth consists of a digital pressure gauge with a tethered temperature clamp. Sporlan was showing off a set of digital pressure and temperature devices with Bluetooth connectivity. They also rely on the connected device for a display. 

All Bluetooth devices were not gauges - Fluke and UEI were showing Bluetooth enabled digital multi-meters and clamp amp meters. 

All these devices were showing apps designed to work with the device and extend its usefulness. Most can be freely downloaded. The i-manifold app is a killer app that is useful even if you don’t have an i-manifold. The Stride folks are hoping you will get tired of typing in the pressures and temperatures and pick up an i-manifold. One final consideration – If your gauges, multi-meter, thermometers, and vacuum gauge are all connecting to your phone while you work, you are going to need some extra juice to keep operating. You will need an extra battery pack or two for your phone, most phones won’t operate all day long without a recharge.