Or is there? This saying is an old adage in our industry to let the technician know that the refirgerant charge is "all set". You see, there must be a steady stream of liquid to the metering device for it to function properly. For sake of conversation, let's use the TXV. In order for most TXV's to throttle and correctly maintain the desired Superheat, there must be a minimum of 2F of subcooled liquid at the valve (not where it is measured, near the condenser). If the liquid were to flash off ahead of the valve, destruction to the TXV may occur. So, some old timer along the way figured he would look into the sight glass (what we install in residential air-conditioners this day and age are moisture indicators), and determine if there was a steady stream of liquid, or in other words: "No Bubble, No Troubles!". For years, this method combined with "beer can cold", or "sweating back to the compressor" were used to determine the refrigerant charge was 'close enough'. Those that know me know that I speak from experience here, I have tried them all!
What we were missing was the fact we were overcharging systems, significantly. Sometimes to the point of slugging compressors, particularly with fixed orifice systems. Having a steady stream of liquid does not mean the refrigerant charge is correct! I know, I am preaching to the choir here. You see, if you are reading my blog than you care enough to learn how to do things right. I am sure you have picked up an installation manual recently and actually flipped through it, instead of kneeling on it and tossing it into the trash! If you have, you will notice that no where in these books does it read, "No Bubbles, No troubles!" If it were that simple, than they would have put it into the start-up procedure. Do me a favor: stop wasting energy and killing compressors, okay? Take the extra ten minutes to measure the Superheat and Subcooling on the system, and verify they are within manufacturer specs. Believe me, you will have less warrantied labor work where you make zero profit replacing compressors!

http://excessair.blogspot.com/p/blog-page_23.html

Views: 87

Comment

You need to be a member of Home Energy Pros to add comments!

Join Home Energy Pros

Home Energy Pros

Home Energy Pros was founded by the developers of Home Energy Saver Pro (sponsored by the U.S. Department of Energy,) and brought to you in partnership with Home Energy magazine.

Latest Activity

Hal Skinner replied to Richard Beyer's discussion Media Reports Spray Polyurethane Foam Insulation spontaneously combusted a $5M Connecticut Home... "The Conclusion"
""fire origin had overheated and ignited during the curing process." No attorney…"
12 hours ago
John Nicholas replied to Sean Lintow Sr's discussion Blower Doors & Methods Used in the group Best Practices (Residential)
"Different houses, different problems, different approaches. A multipoint gives you a slope. The…"
22 hours ago
John Nicholas replied to Sean Lintow Sr's discussion Blower Doors & Methods Used in the group Best Practices (Residential)
"Bud,  I pretty much agree with Sean's points.  Given the time it takes to set up the…"
22 hours ago
Bud Poll replied to Sean Lintow Sr's discussion Blower Doors & Methods Used in the group Best Practices (Residential)
"A multi-point will take longer, but what will it do for the home owner?  Will it change the…"
yesterday
Sean Lintow Sr replied to Sean Lintow Sr's discussion Blower Doors & Methods Used in the group Best Practices (Residential)
"Hmmm good question - personally for air-leakage I would go with multi-point, preferably run from…"
yesterday
Richard Beyer posted a discussion

Media Reports Spray Polyurethane Foam Insulation spontaneously combusted a $5M Connecticut Home... "The Conclusion"

OFFICE OF THE FIRE MARSHAL1212 WHITTEMORE RDMIDDLEBURY, CONNECTICUT Fire Investigation Report –…See More
yesterday
Profile IconDavid Hepinstall and Matthew joined Home Energy Pros
yesterday
Steve Leombruno posted a blog post

Static power energy box

Just wondering if You've heard of this Static power energy box that boasts energy consumption…See More
yesterday

© 2015   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service