Saturday, September 13, 2014

Keep the Condensnot Moving!



The evaporator condensate drain is often one of the last things run when installing an air conditioner and sometimes is not given a lot of thought. The trouble is it can demand your attention if it does not work. A check list for constructing a working condensate drain that will continue to work and be easily maintained would be
1. The drain should have cleanouts near the unit and the trap to allow for routine maintenance.
2. Draw through coils should always have a trap after the drain pan.
3. The trap should be 4” deep and hold 2” of water.
4. The leaving side of the trap should be at least 2 inches lower than the drain pan outlet.
5. After leaving the trap, the condensate line should slope at least 1/8” per foot.
6. Except for the one trap at the unit, the condensate line should NEVER run up.
7. Long condensate lines may require a vent. If you install a vent, you MUST install a trap and the vent must be AFTER the trap, never before the trap.
8. In humid areas the parts of the condensate line closest to the unit may need to be insulated to prevent sweating.

Cleanout
Drains are getting a little more attention these days because the newer mechanical codes require cleanouts. In the past condensate drains were often cleaned by cutting out the old trap, blowing out the line, and installing a new trap. Now you are required to leave a way to access and clean the drain without cutting into it. Some people use tees or crosses at places where elbows would normally go. You can also purchase some fittings to install in the drain line that make accessing and cleaning the drain line easy. One is called “ALL-Access” Link http://www.allaccessdevice.com/
Another is offered by Rectorseal http://www.rectorseal.com/index.php/easy-klear/
Rectorseal also makes a manufactured trap which is clear, allowing you to see when the trap is full of “condensot.” It has service access built in as well. http://www.rectorseal.com/index.php/ez-trap/

Trap
A trap is always required with a draw through coil, otherwise, water will be held in by the negative pressure and the air flowing in through the drain. Many people don’t trap positive pressure coils, such as a coil installed on a furnace. Usually, they will drain because the pressure is pushing the water out. One argument for leaving the trap off on positive pressure coils is that traps tend to get clogged more quickly with “condensnot,” the slimy brown algae that grows in drain pans and drain lines. However, if the air velocity on a blow through coil is high enough, it may still have a negative pressure at the drain outlet. Adding a trap on a blow through coil also provides an air seal between the coil and the outside Manufacturers often specify traps even on blow through coils. Packaged units often specifically warn NOT to trap because they sometimes have a built in trap, and adding another would amount to double trapping. The trap needs to hold enough water to offset the negative pressure of the coil. A common specification calls for a 4” deep trap with a 2” riser so that the trap holds 2” of water and the outlet is 2 “ below the drain pan outlet.

Vent
Ever notice that plumbing systems have vents? The vent keeps the draining water and effluent from creating a suction which can slow or even stop drainage. On longer condensate lines, a vent may be required to insure drainage. Vents can also help on lines with minimal slope. The vent is just a tee with a riser which is open to the air. When used, there MUST be a trap and the vent should be AFTER the trap. Putting a vent before the trap pretty much undoes any good the trap would do by allowing air to pass through the vent. The vent should be at the start of the condensate line (but after the trap) and the riser should go above the rim of the drain pan.  

Slope
One of the laws of plumbing is that waste products run down hill. After the line leaves the trap at the unit it should never go back up. Running the line up after dropping down creates a second trap. Remember that the line is not under pressure, it is gravity flow. It is easy for “condensnot” to accumulate at this second trap and cause the drain to overflow at the unit. I am embarrassed to admit that I have personal knowledge of this. An unintended second trap is a messy service call waiting to happen.

Insulation
If your unit runs a lot and the coil is located in a humid area, the condensate line can sweat. Usually, the PVC is enough insulation to prevent this, but in some areas people have had problems with dripping condensate lines from sweating. Insulating the trap and all the drain between the trap and the unit with armaflex takes care of this.

Instructions
Finally, always follow the manufacturer’s instructions. They usually are pretty specific about how the drain is to be run. Trapped or not trapped, vented or not vented – those things are all typically in the instructions. Here is a link to another online posting that shows one manufacturer’s instructions and a drain run according to those instructions. 

Thursday, September 11, 2014



Thirteen years ago, I was working in my office at school when a teacher from down the hall came in and said that a plane had flown into one of the World Trade Center towers. While I was searching for information about the first plane, the second plane hit the other tower. It was only then that I realized we were under attack. The trade center towers were chosen because they became an icon of American strength. The terrorists intended to strike fear into our hearts by taking down our most visible symbols of strength and power. Rather than weaken us, we proved our mettle immediately following the tragedy. Stories abound about how people rose to the challenge: from police and firemen risking their lives to politicians speaking with one voice as Americans. My favorite story involves St.Paul’s Chapel directly across the street that provided round the clock care and support for eight months to the rescue and recovery workers. Volunteers came from all over America to work there. So many volunteers came that they had to be scheduled and their time helping was limited to allow everyone a chance to experience the blessing of helping. People cried when their time was up and they had to leave.  
The towers came down. The strength remains.

Friday, September 5, 2014

Left Handed Piano



I took Labor Day weekend off from blogging, I hope you didn’t miss reading my weekly post too much. Actually, I hope that you REALLY, REALLY missed it and can’t wait for the next article. One of the great things about Labor Day is the chance to spend time with your family relaxing, telling stories, and recalling family history and legend. One story about my grandmother struck me because it so clearly describes her. She contracted Parkinson’s disease as a young woman. In fact, I never knew her when she did not have Parkinson’s. Dad tells the story of her first meeting with the doctor to look for a treatment for her Parkinson’s. Grandad had taken her to a doctor to see if L-Dopa would help her. The doctor asked “Mrs. Stanfield, how long have you been disabled?” to which she quickly shot back, “I am NOT disabled!” The doctor tried a different approach. “How long have you had trouble walking?” Grandmother,” I walk just fine, thank you!” The doctor tries again, “Can you walk across the room for me please?” Grandmother gets up and slowly walks across the room, dragging her right leg behind her. In her mind, she was NOT disabled. She got where she needed to go and did what she needed to do. The palsy also crippled her right hand. She had been a world class piano player, but now she could not open her right hand. She started playing left handed piano music. When she died, she had a large collection of left handed piano music – music written intentionally for ONLY the left hand. With her one palsied hand, she could play better than 99% of the rest of us who have two good hands. She was a very able woman. You did not dare call her disabled or tell her what she could not do. There are many young people returning home who suffered a multitude of injuries while serving overseas. Our industry needs their talent and abilities. Please, lets give them a chance to play some left handed piano.

Saturday, August 16, 2014

Caught One!

The lead story of the August 11, 2014 Air conditioning Heating and Refrigeration NEWS is “Man Gets Prison Time for Venting R-22.” In this particular case he was stealing copper – he just did not bother to recover the refrigerant first. The police literally caught him in the act, and knowing what he did was a Federal violation, reported him to the EPA. Now he is serving 31 months in prison. Truthfully, most people who steal copper or vent refrigerant are not caught. However, this case proves that you CAN be caught, and there is a substantial penalty.  Some people do the right thing because that is the way they conduct their lives. Others need some external reinforcement to avoid doing what they know they are not supposed to do.  Without penalties for breaking the rules, these folks will ignore the them. Hopefully this incident will be widely publicized so that other potential thieves in need of external reinforcement will consider another line of work. Or at the very least, steal something that does not involve venting refrigerant.

Here is a link to the story Prison Time for Venting Refrigerant

Sunday, August 10, 2014

Oxy-Acetylene Torch Safety

One of my e-buddies, Dave Christensen, suggested that I write about oxy-acetylene torches. He recently bought a new torch and confessed that he read the instructions before using it. In the instructions, he noticed that the regulator settings were different from the ones he had used for years. When we teach students to use torches in school, we typically teach them the regulator settings that work for the equipment we have. I am afraid we may not always make sure students understand that torch settings are not universal. The correct regulator setting depends upon the torch manufacturer, the tip size, and the application. Torch manufacturers typically provide these settings in the instructions.

There are a few guideposts that stay the same. For example, you NEVER, NEVER, NEVER set acetylene above 15 psi. In fact, I get nervous above 10. The reason is that acetylene is unstable at pressures above 15 psi and can explode. So how does it not explode in the acetylene cylinder at 250 psig? It is dissolved in acetone liquid which is stabilized in a porous core. That is why you should never transport or use acetylene cylinders on their side – it lets the liquid run out of the cylinder into the valve area. Also, you really don’t need the oxygen above 20 psig. Many tip charts have it about half that for most applications. However, the exact settings you should use are ... in the instructions!

Another common safety issue is leaving your regulators set and just opening and closing the tank valves when you want to use the torch. This is convenient and saves time, but it is dangerous. Regulators can fail because of the sudden bump in pressure. This can cause parts to fly and high pressure gas to stream down the hoses. The last thing you should do when shutting off your torch is to adjust the regulator T handles out counterclockwise until all the spring pressure is released. When the cylinder valves are opened they should be in this position. AFTER opening the cylinder valves you can adjust the regulators to he correct pressures.

When lighting the torch, you should light the acetylene first by itself and then bring in the oxygen. Opening both the acetylene and oxygen simultaneously can cause oxygen to flow into the acetylene hose and regulator if the oxygen pressure is higher than the acetylene pressure. This can create a very dangerous situation – a mixture of fuel and oxygen under pressure in the hose and regulator. The only place we want this type of combustible mixture is in the tip.  When shutting down, reverse the process. Close the oxygen first and then the acetylene.

Torch manufacturers have some very good training material available for free. Here are some links to some good training resources.

http://training.victortechnologies.com/

http://www.harrisproductsgroup.com/en/Products/Equipment.aspx

http://uniweld.com/en/uniweld-videos

Saturday, August 2, 2014

Stubby Gauges

Anyone who has ever disconnected a hose from a Schrader valve knows about the spray you get as a result. If you are taking a hose loose from the liquid line there can be quite a lot of very cold refrigerant spraying out. Many people don’t realize that the spray is usually NOT coming from the Schrader valve, but from the hose! The spray is from refrigerant that is trapped in the hose coming back out when you loosen the hose. By my calculations a standard 5 foot 1/4” hose holds about 3.5 ounces of R22 liquid. Releasing it is bad for the atmosphere, bad for the system, and bad for you if it gets on your skin. If the system was perfectly charged before you connected your gauges, it is no longer after you take them off.  If you were to connect a 5 foot hose to the liquid line of a dorm refrigerator and fill up the hose, you would essentially suck most of the charge out into your hose and gauges. Of course you would first have to install a piercing valve or two – creating potential leaks to boot.

My point is that you don’t always need to connect your gauges to every system you see – especially small critically charged systems. Even on larger systems, if you are connecting gauges just to check the system operation, consider getting a couple of “short gauges.” These are essentially a gauge mounted on just enough tube to connect it to the system. They hold a minimal amount of refrigerant, so the amount released is much less. This saves the atmosphere, is better for the system, and is way better for your fingers. Here is a link to a picture of a set of stubby gauges used in an article on ice machine service found in Contracting Business Magazine.



Sunday, July 27, 2014

EPA Proposes Ban on R-404A and Other Refrigerants

You may have heard that the EPA is proposing to ban the use of some common refrigerants  I would like to give a brief overview of things you should know about this proposed ruling. First – at this stage it is still a proposal – not a ruling. Typically the way this works they publish a proposed ruling, allow us to comment on it, revise the ruling based on the comments (if they choose to), and publish the final ruling.  Since this is still a proposed ruling, you have a little time before it will take effect. Second, not all industries are affected by this ruling. Air conditioning caught a break – air conditioning systems are not covered . However, motor vehicle air conditioning IS covered. For motor vehicle air conditioning the big news is that 134a will no longer be acceptable in NEW VEHICLES beginning January 2016. A large number of zeotropes are also banned from use in new vehicles, but most of those are mainly used today as an R12 substitute. That should not have a great effect because they are only banned in NEW vehicles.

Retail refrigeration appliances and vending machines are also covered. The big news here is that R507 and R404A will be considered unacceptable for both new AND retrofit applications in retail refrigeration beginning January 2016. Retail refrigeration would include things such as display cases in grocery stores.

Four areas that are NOT covered by this proposed rule (yet) include cold storage warehouses, ice machines, refrigerated transport, and industrial process  refrigeration. However, the EPA is specifically asking for comments about the possibility of using low GWP refrigerants in these areas as well.
 “EPA requests comment on the use and viability of both low-GWP refrigerants (e.g., R-744, R-717, and HCs) and other HFC-blends (e.g., R-407A and R-407F) and the possibility of listing R-404A, R-507A, and other high-GWP blends unacceptable in any or all of these four end-uses.” I encourage you to do some of your own research into this. Here is a link to the proposed RULING. Here is a link to a FACT SHEET about the ruling. Here is a table summarizing the proposed changes to the auto air conditioning and retail refrigeration refrigerants.


Refrigerant Uses Deemed Unacceptable as of January 1, 2016
End-use
Substitute
Further Information
Retail food refrigeration (new and retrofit)
R-404A
R-404A is a blend, by weight, of 44% HFC-125, 4% HFC-134a, and 52% HFC-143a. It has a high GWP of approximately 3,920. Other substitutes are available for this endues with lower overall risk to human health and the environment.
Retail food refrigeration (new and retrofit)
R-507A
R-507A is a blend, by weight, of 50% HFC-125 and 50% HFC-143a. It has a high GWP of approximately 3,990. Other substitutes are available for this end-use with lower overall risk to human health and the environment.
Retail food refrigeration (condensing units and supermarket systems) (new)
HFC-227ea, R-407B, R-421B, R-422A, R-422C, R-422D, R-428A, R-434A
These refrigerants have GWPs ranging from 2,729 to 3,607. Other substitutes are available for this end use with lower overall risk to human health and the environment.
Retail food refrigeration (condensing units and supermarket systems) (retrofit)
R-407B, R-421B, R-422A, R-422C, R-422D, R-428A, R-434A
These refrigerants have GWPs ranging from 2,729 to 3,607. Other substitutes are available for this end use with lower overall risk to human health and the environment.
Retail food refrigeration (stand alone units only) (new only)
HFC-134a
HFC-134a has a Chemical Abstracts Service Registry Number (CAS Reg. No.) of 811-97-2 and it is also known by the name 1,1,1,2-tetrafluoropropane. HFC-134a has a relatively high GWP of 1,430. Other substitutes are available for this end use with lower overall risk to human health and the environment
Retail food refrigeration (stand alone units only) (new only)
FOR12A, FOR12B, HFC-227ea, IKON B, KDD6, R- 125/290/134a/600a (55.0/1.0/42.5/1.5), R-407A, R-407B, R-407C, R-407F, R-410A, R-410B, R-417A, R-421A, R-421B, R-422A, R-422B, R-422C, R-422D, R-424A, R-426A, R-428A, R-434A, R-437A, R-438A, RS-24 (2002 formulation), RS-44 (2003 formulation), SP34E, THR-03.
These refrigerants have GWPs ranging from approximately 550 to 3,607. Other substitutes are available for this end-use with lower overall risk to human health and the environment.
Vending machines (new and retrofit)
R-404A
R-404A is a blend, by weight, of 44% HFC-125, 4% HFC-134a, and 52% HFC-143a. It has a high GWP of approximately 3,920. Other substitutes are available for this endues with lower overall risk to human health and the environment.
Vending machines (new and retrofit)
R-507A
R-507A is a blend, by weight, of 50% HFC-125 and 50% HFC-143a. It has a high GWP of approximately 3,990. Other substitutes are available for this end-use with lower overall risk to human health and the environment.
Vending machines (new only)
HFC-134a
HFC-134a has a Chemical Abstracts Service Registry Number (CAS Reg. No.) of 811-97-2 and it is also known by the name 1,1,1,2-tetrafluoropropane. HFC-134a has a relatively high GWP of 1,430. Other substitutes are available for this end use with lower overall risk to human health and the environment
Vending machines (new only)
FOR12A, FOR12B, IKON B, KDD6, R- 125/290/134a/600a (55.0/1.0/42.5/1.5), R-407C, R-410A, R-410B, R-417A, R-421A, R-422B, R-422C, R-422D, R-426A, R-437A, R-438A, RS-24 (2002 formulation), SP34E.
These refrigerants have GWPs ranging from approximately 550 to 3,085. Other substitutes are available for this end-use with lower overall risk to human health and the environment.