Those temp and pressures you used as an example would be right on for 13 seer and above r-22 equip. Obviously this would be a problem on a 410-a system. You would be either overcharged, or a high side restriction. If your overcharged your suction would be high too. With a restriction your suction would most likely be low. Now if your measuring your entering wet bulb temperature, I'm guessing your working with Trane ? If your doing startup on new equipment, then the chart is there for you. That is a beautiful thing. You can get it nuts on. No questions asked. This is provided the equipment was installed correctly. Your on the right track. Charging a system correctly is very important. You would be surprised how many tech's can't do this. This will make you a cut above the rest. You can be a great tech, not because your a great tech, but because a lot of tech's are idiots. I hate to say this, but it's true.
These are just examples, and R- 22 would be much lower. I do use slide ruler and always make sure my pressures and sub cool are inline. I do not over charge systems. I am just not sure of temperatures and pressures our a/c season is just starting and in three weeks I will get back into groove. My numbers will come back to me.
Originally Posted by beenthere
Those temp and pressures you used as an example would be right on for 13 seer and above r-22 equip.
What?
R22 at 280PSI has a saturation temp of 125*F. What 13 SEER unit runs that high of a head.
Even the old 35* over OD ambient would run a lower head pressure then that.
Most trane's used to use the approach method. it is liquid line over ambient. The newer tranes say you can use the approach or sub cooling method. The sub cooling is easier for me
Originally Posted by kw10925
I am learning the trade, and my boss is giving me jobs.
Is trane XL1200 superheat or subcooling.
I am trying my best,I want todo it correctly not half ass.
How do you know if you have a piston,tev,and a txv
I know piston is sh , but getconfussed with tev sh or sc
Know txv is sc. PLEASE HELP
These are just examples, and R- 22 would be much lower. I do use slide ruler and always make sure my pressures and sub cool are inline. I do not over charge systems. I am just not sure of temperatures and pressures our a/c season is just starting and in three weeks I will get back into groove. My numbers will come back to me.
The only reason why I only do sub cooling and not super heat is because my time is a little more valuable than yours. Hope you like my answer.
The most important thing I am worried about is that I Try and achieve close to 20 * delta T without going to much over and freezing coil. Super heat is for turtles. I wear running shoes.
Originally Posted by jrbenny
I can't imagine why a HVAC technician would only measure one side of the system.
The only reason why I only do sub cooling and not super heat is because my time is a little more valuable than yours. Hope you like my answer.
The most important thing I am worried about is that I Try and achieve close to 20 * delta T without going to much over and freezing coil. Super heat is for turtles. I wear running shoes.
For the little extra time it takes to check super heat. No ones time is that valuable, that they don't have the time.
Originally Posted by beenthere
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R-410 is always higher 1.5 times higher. I just can't remeber exact numbers for temperatures, thats why I use a slide ruler always.