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Photograph of a commercial air conditioning compressor charging gauge set (C) InspectAPedia.com R-410a Refrigerant Pressure Readings
R-401A pressures, quantities, data

R-401a refrigerant charge quantity for air conditioners & heat pumps:

This air conditioning repair article series discusses the the diagnosis and correction of abnormal air conditioner refrigerant line pressures as a means for evaluating the condition of the air conditioner compressor motor, which in turn, is a step in how we evaluate and correct lost or reduced air conditioner cooling capacity.

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Typical R-410A Refrigerant Pressure / Temperatures

For every refrigerant type you use, you'll want to pick up a Refrigerant Pressure/Temperature chart from your supplier. A typical R-410A refrigerant pressure/temperature chart will give refrigerant pressures at various (ambient) temperatures ranging from below freezing to over 160 °F. Here are a few examples:

Example R-410A Refrigerant Temperature vs Pressure Data
Ambient Temperature in °F1 R410A Vapor Pressure at Sea Level Temperature (°C) R-410A Low Side Pressure2 R-410A High Side Pressure3
-10°F 26.9 psi -23.3    
0°F 48.4 -17.8    
10°F 62      
32°F 101.4 0    
40°F 119   83 psig 257 psig
45°F 120   130 418
51°F 145      
55°F 155      
60°F 170.7 15.6    
62°F 175      
64°F 180      
66°F 185      
70°F 201      
72°F 205      
73°F 210      
75°F 218.7 23.9 120 psig 410-420 psig
76°F 220      
80°F 236.5 26.7    
82°F 240      
84°F 250      
85°F 254      
87°F 260      
90°F 275      
93°F 290      
95°F 296.4 35    
97°F 305      
100°F 318.6 37.8    
109°F 365      
110°F 366      
118°F 405      
134°F 500      
150°F 613.9 65.6    

Notes to the table above

R410A Refrigerant Rules of Thumb

On a properly-charged and working air conditioning system using R-410A refrigerant

Other Properties for R410A Refrigerant

1. Outdoor ambient temperature

2. Typical low pressure or suction side pressure for R410A is about 120 psi, varying by ambient temperature, here assuming 75°F, may vary by equipment and metering controls

3. Typical high side pressure for R410A is < 600 psi at an ambient outdoor temperature of 95 °F, may vary by equipment

4. These psig readings for R-410A are what you'd expect the pressure of the gas to be in an enclosed container at the temperature given and at steady state.

These pressures are not suction or low-side nor compressor output or high-side pressures as those depend on the compressor model and the refrigerant metering device. This operating pressure for R-410A example was given by ACHR News in 2002:

... to produce an evaporating temperature of 40 degrees F and a condensing temperature of 115 degrees, the suction and head pressures would be 83 psia and 257 psia in an R-22 system, while they would be 133 and 406 psia, respectively, in an R-410A system. - Checket-Hanks, Barbara A., "Guidelines for Troubleshooting R-410A Systems", ACHR News 16 May 2002, retrieved 2016/08/29 original source: http://www.achrnews.com/articles/87788-guidelines-for-troubleshooting-r-410a-systems

An air conditioner or heat pump using R-410A refrigerant may operate at pressures exceeding 600 psi. A typical Carrier HVACR unit incorporates a high-pressure safety switch that operates at 610 psi and a low pressure (loss of refrigerant detection safety device) that operates at about 20 psi.

Low pressure refrigerant switches on Carrier HVACR typically open at 50 psi and close at 100 psi. - Prah, Frank, CMS, "Refrigerant 410A", [PDF] Refrigeration Service Engineers Society, 1666 Rand Road, Des Plaines IL 60016 USA, Tel: 847-297-6464, retrieved 2016/08/29, original source: https://www.rses.org/assets/r410a/R-410A.PDF

R-410A Refrigerant Pressure / Temperature Chart Downloads

Both older R-22 and R-134 operate at lower pressures than R-410A.

Watch out: Excerpts from Carrier’s Puron® Quick Reference Guide

“When charging 410A (liquid refrigerant only), use a commercial-type metering device in the manifold hose when charging into the suction line with the compressor operating.”

“Manifold sets should be a minimum 700 psig on the high side and minimum 180 psig low side, with 550-psig low-sided retard. Use hoses with a minimum 700-psig service pressure rating.”

“Be sure that servicing equipment and replacement components are designed to operate with [410A].” The recovery cylinder service pressure rating must be 400 psig, DOT 4BA400, or DOT 4BW400.

R410A Evaporating & Condensing Temperatures

Example R410A Evaporating & Condensing Temperatures & Suction & Head Pressures vs bulb temperatures
Evaporator Temp °F Condenser Temp °F Suction Pressure psia Head Pressure psia Indoor Temp °F
Dry Bulb		 Outdoor Temp °F
Dry/Wet Bulb
40°F 115°F 83 257    
    86 299 60°F 30/28°F 4
    103 329 60°F 40/38°F 4
    124 379 60°F 50/47°F 4
45°F 120°F 130 418   3
    146 430 60°F 60/57°F 4
    145 461 70°F 60/57°F 4
    144 490 80°F 60/57°F 4

Notes to the table above

  1. To charge correctly, use the subcooling method
  2. Typical pressure range at 75F: suction side 100-120 psi
  3. HVAC Education Australia, The Essentials Of Working With R-410A [PDF] [no contact information given except website as cited below] retrieved 2019/02/11 original source: http://www.hvaceducationaustralia.com/Resources/PDF/The%20Essentials%20Of%20Working%20With%20410A.pdf
  4. R410A HEAT PUMP HEATING CHECK CHART PAYNE PH16NA [PDF] for 16 SEER 2-Stage Split System Heat Pump using R410A, 2-5 Tons, (2012) Payne Heating & Cooling Systems, 7310 W. Morris St. D Indianapolis, IN 46231 USA, retrieved 2019/02/11
  5. Suction side: add 25°F to outside air temperature and use the refrigerant chart to convert to psig
  6. ACHR News, "Guidelines For Troubleshooting R-410A Systems" ACHR News, Main Office 2401 W. Big Beaver Rd., Suite 700 Troy, MI 48084 Phone: 248-362-3700 retrieved 2019/02/11 original source: https://www.achrnews.com/articles/87788-guidelines-for-troubleshooting-r-410a-systems<

Correcting R-410a Refrigerant Pressure & Leaks

Refrigerant Pressures & Pressure Diagnosis

Refrigerant Pressure & Leak Correction

If you already know your refrigerant pressures are wrong or that you have a refrigerant leak, please see

If your air conditioning or heat pump system has lost its cooling capacity or won't start see

...


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Reader Comments, Questions & Answers About The Article Above

Below you will find questions and answers previously posted on this page at its page bottom reader comment box.

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2020-04-09 - by (mod) -

Yes, Carl, and thanks for asking.

"Around 40" - are you referring to ambient temperature, refrigerant line temperature or something else?

Typically on a heat pump on the suction line the saturation temperature will be set to about 20 to 25 degrees F below the outdoor ambient temperature.

The refrigerant doesn't know if it's being used in heating mode or cooling mode; the temperature/pressure charts for R410A as well as for other refrigerants only present pressure and temperature ranges.

On 2020-04-09 by carl

when installing 410a is the pressure gauge around 40
the same on a heat pump as it is on a regular air conditioner

On 2020-02-10 - by (mod) -

Dave, take a look in the refrigerant pressure tables given in the article on this page - for R410A for example.

When the A/C system is OFF and has been off long enough for pressures to equalise across the thermostatic expansion valve, both high-side and low-side pressures will be the same.

The measured pressure of the refrigerant, when the compressor has been off for a time and the HI and LO sides are equalized, is simply a function of the ambient pressure and of course your elevation above sea level.

For example, R410A, at an ambient temperature of 60°F will have a pressure of 170.7 psi.

When the unit is operating the head pressure goes up and the suction side pressure goes down. We describe operating pressures in tables and in notes to the tables given here.

For example,
Typical low pressure or suction side pressure for R410A is about 120 psi, varying by ambient temperature, here assuming 75°F, may vary by equipment and metering controls

Typical high side pressure for R410A is < 600 psi at an ambient outdoor temperature of 95 °f, may vary by equipment

thank you for asking.

On 2020-02-10 by Dave Wane Plumbing

On a split system air conditioner, what should the approximate pressures be at condensing unit using 410A or 32A when the unit is off?
And what should the pressure be when the unit is operating?

Question:

2019/08/10 Karl Seyer

I have an AC compressor using R410, can I use an older gauge, or is the pressure too high for the the old Refrigerants, like R12 & R35?

Reply:

The pressure range will be within your older gauge set and in fact you may see an R-410a scale on the gauge face of some equipment.

...

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