Search unanswered questions...
Enter a question here...
Questions Reference

What is the correct pressure on the high side and the low side of an efficiently working system?

[Edit]

High side <200psi. Low side <50 lb.
"A good rule of thumb with R134a is to run fan on High with all windows open and engine at 1500 rpm. High side pressure in PSI should be about 2.2 to 2.5 times outside air temperature in degrees F"

I, myself, am not trolling for customers or to gratify my superiority, unlike some others.



Answer

There are NO easy answers to this. Most manufacturers provide a chart or charts that will assist in determining what those pressures will be. The variables that will affect those pressures include, but are not limited to: Outdoor ambient temperature Outdoor relative humidity Indoor entering temperature (wet bulb or dry, depending on rel. humidity) Unit and duct sizing and proper airflow through system

Some techs will use "rules of thumb" and dead reckoning that may have worked in the good old days, but with ever rising costs, newer systems are more demanding and a simple refrigerant miscalculation could cause performance problems resulting in comfort concerns or higher power bills.

Answer

If this is true, then why do the gauges you use have a chart on them that tells what the high side range and low side range should be? Also, if this is such a cryptic answer, then why can I buy these gauges at a tool store for about $20?

Answer

The low side should be anywhere from 65-80 psi (40 degree coil temp) The high side should correlate with the outside temp...

The gauges have pressure temp for each type of freon being used,for example using R-22 freon on a outside ac unit,40 degrees will equal to 70 psi on the gauges (suction/low side) gauge

Answer

Sure, you can buy guages at a tool store. I fix a lot of repairs made by do it yourselfers. The chart on the guages are for corresponding pressure to temperature, not to tell you how much gas to put in. The best, most comprehensive measurement is superheat: suction pressure converted to temperature and a measurement of suction line temperature. this tells you how the refrigerant is acting in regards to the total (sensible and latent) amount of heat it is removing from the air.

Improve Answer Discuss the question "What is the correct pressure on the high side and the low side of an efficiently working system?" Watch Question

First answer by ID1181617847. Last edit by Uniberp. Contributor trust: 56 [recommend contributor]. Question popularity: 113 [recommend question]

Research your answer:

Answers.com > Wiki Answers > Categories > Home and Garden > Home Improvement > Heating Ventilating and Air Conditioning > What is the correct pressure on the high side and the low side of an efficiently working system?

Our contributors said this page should be displayed for the questions below. (Where do these come from)
If any of these are not a genuine rephrasing of the question, please help out and edit these alternates.
Low side pressure?  High Side Pressure Limit?  Freezer low side pressure?  Grand AM low pressure side?  Suburban high side pressure?  Ac high and low side numbers?  Where is the high pressure side?  How do you read low and high side?  What shuold the low high side show?  High side low side pressure for r22?  What should the low side pressure be?  Auto ac high side pressure for r-415b?  Which is the low side and the high side?  404a low and high side pressure freezer?  Where is the high side on dodge caravans?  Where is the low side of ac on 95 windstar?  Why did the high side freeze up on your ac?  Correct low side pressure in a refrigerator?  What should the pressure be on the high side?  What should the low side pressure be for r22?