R410a High Side PressureHoses with a service pressure rating of 750 PSI should be used. CTM High Pressure Switch / Marine Air Conditioning Pressure Switch - R410A - 450-575 psi. 4°F(-3C°) Target evaporation temperature setting Higher setting. Even in cold and dry countries, inefficient heat transfer due to dirty mini splits can push the high side pressure to around 300 psi. For 410a, what should the high and low side pressures be? With a 500-psi low-side retard, manifold sets should be set at 750 psi (high side) and 200 psi (low side). R-22 and R-410A Operating Pressures, Charging and Recovery Setup! In this article, we will discuss an HVAC unit’s refrigerant pressure on both the high side and the low-pressure side while the system runs. 5°C) 84 psi R410A 115°F (46°C) 406 psi 43°F (6. A normally operating R-410A system with the same condensation temperature of 120 degrees and a 45 degree evaporator saturation temperature will have. Use hoses with a minimum 700-psig service pressure rating. R410A has a GWP > 2,000. i just installed a new split unit r-410a a/c system. However, if you rewind just fifteen or twenty years you would find that very little people even knew about it. R410a suction pressure may be around 120psi, and R410a head pressure may be anywhere from 225psi to 350psi. What is the normal low side pressure for 410a HVAC system? 2. The normal pressure for a typical R-401A mini-split ranges from 110-140 psi. Improper operating pressures - too high: Refrigerant pressure will be increased on both the high side and low side of the system; More expensive operation: The system may still be able to change state, but at a higher temperature than intended, thus in an air conditioner, it won't cool as effectively nor as efficiently as with the proper charge. Typical high side pressure for R410A is < 600 psi at an ambient outdoor temperature of 95. 99 Featured items you may like Page 1 of 1 Start over Amazon Basics 2-Piece Nut Driver Set - 6mm and 8mm 184 1 offer from $18. The pressure of the refrigerant corresponds with the temperature. Digital Fieldpiece Gauges: https://amzn. Unit was making a funny noise. 1 high side line temp. high side actual line temp near the indoor unit : 25 C. This item: PT Chart R22/R-410A Laminated Pocket Aid Pressure / Temperature # 34-3400-02 $7. In the example of an R-410A packaged unit with a surrounding air temperature of 75°F, the pressure on both the high and low-pressure side of the system will be 217 PSIG. Digital Fieldpiece Gauges: https://amzn. the correct orifice is installed. Most refrigerant blends boil at different rates and require complete evacuation before adding a full charge. Improper operating pressures - too high: Refrigerant pressure will be increased on both the high side and low side of the system More expensive operation: The system may still be able to change state, but at a higher temperature than intended, thus in an air conditioner, it won't cool as effectively nor as efficiently as with the proper charge. With this higher pressure from 410A comes a need for new tools. R-410A, or Puron, is one of the most popular refrigerants in today's modern world. It's been my experience the color of the seal notes the pressure range you just need to look it up. Digital Fieldpiece Gauges: https://amzn. r-410a pressure temperature chart psig f° psig f° psig f° psig f° psig f° psig f° 12 -37. See THERMOSTATIC EXPANSION VALVES or See CAPILLARY TUBES Water (moisture) contamination in the refrigerant system. R-410A is currently being phased in for residential use as the phase period for R-22 draws nearer. 1/4” female SAE mounting Automatic Reset Tamper. How to adjust low side pressure on 410a HVAC system? 4. A refrigerant restriction is indicated by a. What Should my AC Pressures Be for R410A. Intro What Should my AC Pressures Be for R410A Refrigerant Benjamin Sahlstrom 376K subscribers Subscribe 5. It will be likely running in the 35 to 45f degree saturation (boiling point) range, 108 to 131 psi. Called my installer back out and the low side pressure was 150-175 and the high side was 500-800 with some clicking and relief squealing going on (funny noise). “Manifold sets should be a minimum 700 psig on the high side and minimum 180 psig low side, with 550-psig low-sided retard. The TXV is backed all the way out. Use hoses with a minimum 700-psig service pressure rating. 1F + or minus Temp from supply side: 55. R404A is a hydrocarbon refrigerant that has a high pressure level of 1,500 psi. High suction line pressure in a 410a system? I'm currently being humbled by a 3 year old, 5 ton 410a system. According to experts, the working pressure should never be less than 100 psi or more than 160 psi. Using a PT chart or pressure temperature chart one can determine the pressure or the temperature of the refrigerant. r410a high/low pressures Residential 410a system as follows: Liquid line: ~400psi ~ 30 subcool Vapor line: 105psi ~30 superheat The LLFD does not feel cold. " "Be sure that servicing equipment and replacement components are designed to operate with [410A]. Saturation Pressure-Temperature Data for R410A (psig)* Temp (°F) Pressure Temp (°C) Temp (°F) Pressure Temp (°C) Temp (°F) Temp (°C) Pressure Temp (°F. R-22 and R-410A Operating Pressures, Charging and Recovery Setup! In this article, we will discuss an HVAC unit’s refrigerant pressure on both the high side and the low-pressure side while the system runs. R404A and R410A are two refrigerants that are commonly used in AC units. R410A PT Chart: -60°F To +155°F Pressure Temperature Chart. The unit was charged in heating mode and 11lbs 1 oz of refrigerant was used. Intro What Should my AC Pressures Be for R410A Refrigerant Benjamin Sahlstrom 376K subscribers Subscribe 5. High side pressure: 335psi = 104 saturation temp. And I sleep at night of course. R410A is one of the most commonly. For 410a, what should the high and low side pressures be? With a 500-psi low-side retard, manifold sets should be set at 750 psi (high side) and 200 psi (low side). Check the high-pressure gauge, right-hand side, on the R-410 manifold set. However, keep in mind that the working pressure depends on factors like cooling load and weather. A normally operating R-410A system with the same condensing temperature of 120 degrees and a 45 degree evaporator saturation temperature will have a high side pressure of 418 psig and a low side pressure of 130 psig. 8 (5 degrees) High-side (condensing) pressure (psig): 172 (120 degrees) Here are the calculated values: Condenser split: 50 degrees Condenser subcooling: 30 degrees Evaporator superheat: 10 degrees Compressor superheat: 20 degrees Symptoms Symptoms of this overcharged system include:. System Pressure R-410A. In the example of an R-410A packaged unit with a surrounding air temperature of 70°F, the pressure on both the high and low-pressure side of the system will be 201 PSIG. Let’s take a look: Manifold Gauge Set – The high pressures encountered when working R-410A requires a manifold gauge set that has a low-side gauge that can read up to 500 PSIG and a high side gauge that can read up to 800 PSIG. He looked at evap coil and it was not restricted the fans were blowing good. In the example of an R-410A packaged unit with a surrounding air temperature of 75°F, the pressure on both the high and low-pressure side of the system will be 217 PSIG. Screw-on fittings will screw onto the port, whereas low-loss fittings will snap into place. “Manifold sets should be a minimum 700 psig on the high side and minimum 180 psig low side, with 550-psig low-sided retard. The pressures will vary as the operating conditions like return air temperature, outdoor temperature change. First thing, convert psi to MPa. This item: PT Chart R22/R-410A Laminated Pocket Aid Pressure / Temperature # 34-3400-02 $7. the high side seems way low, should be about 420. i just installed a new split unit r-410a a/c system. 1K 318K views 3 years ago A/C Repair Digital Fieldpiece Gauges: https://amzn. A refrigerant restriction is indicated by a high discharge pressure and a low suction pressure. Symptom was not cooling enough. r-410a pressure temperature chart psig f° psig f° psig f° psig f° psig f° psig f° 12 -37. ” “Be sure that servicing equipment and replacement components are designed to operate with [410A]. High side pressure: 335psi = 104 saturation temp. A normally operating R-410A system with the same condensation temperature of 120 degrees and a 45 degree evaporator saturation temperature will have a high side pressure of 418 psig and a low side pressure of 130 psig. The first thing to realize is that when a system is off and equalized, the system’s pressures on both the high side and the low-pressure side will match. A normally operating R-410A system with the same condensation temperature of 120 degrees and a 45 degree evaporator saturation temperature will have a high side pressure of 418 psig and a low side pressure of 130 psig. An azeotrope refrigerant blends multiple refrigerant compounds to form a single refrigerant. r410a high/low pressures Residential 410a system as follows: Liquid line: ~400psi ~ 30 subcool Vapor line: 105psi ~30 superheat The LLFD does not feel cold. 1K 318K views 3 years ago A/C Repair Digital Fieldpiece Gauges:. Lastly, it prevents cross-contamination of the oils can cause serious issues between the two types of systems and it is highly recommended to use separate gauges for service providers. the high side seems way low, should be about 420. Since R-410A operates at a higher pressure and a different type of oil is used than R-22 separate gauges should be used to obtain pressures. However, keep in mind that the working pressure depends on factors like cooling load and weather. According to experts, the working pressure should never be less than 100 psi or more than 160 psi. R410A PT Chart: -60°F To +155°F Pressure Temperature Chart. HFC leak detectors should be used. Presostats High & Low Pressure Switches for R22 and R410a Everwell Add to Wishlist Compare Features: SPST switch. High side pressure: 335psi = 104 saturation temp. 2 MPa is the operating pressure (right on the nameplate). It is important to know the range of these pressures in order to understand why and how charging and recovery are performed. R-410A R-410 is also known as “Puron. low side 150 psi. For R410A Refrigerant, 450 - 575 psi. Typical Low Side Pressure Range for R410A in the field: 115-120 psi Typical High Side Pressure Range for R410A in the field: 410-420 psi By 2025, high Global Warming Potential (GWP) refrigerants with a GWP of over 750, will be banned together with the systems using that gas. A normally operating R-410A system with the same condensation temperature of 120 degrees and a 45 degree evaporator saturation temperature will have a high side pressure of 418 psig and a low side pressure of 130 psig. Compatible with CTM, Dometic, and Cruisair. When I figure super heat or sub cool on these saturation temps and line temps my super cool/sub cool show I guess a major overcharge. I have a 3 ton 410a Lennox with correct suction pressure however my high side pressure is way low. R410A is an HFC refrigerant, invented by Honeywell, that has been developed to replace the HCFC refrigerant R22. The first thing to realize is that when a system is off and equalized, the system’s pressures on both the high side and the low-pressure side will match. to/2LFjNnKR410A Equipment: https://amzn. Does this indicate a LL restriction or some other cause? What would be the best way to determine the problem?. Output (high side pressure during operation) is the pressure of the compressed refrigerant gas as it leaves the compressor motor. Usually, the high side pressure of an R410A mini split is between 230-300 psi. 40 HVAC Quick Reference Cards for Refrigerant Charging and Troubleshooting $24. Connect the hose on the manifold's right-hand side, high-pressure side, to the liquid refrigerant's service valve port. ” This refrigerant is recommended for use in. If a new R-410A refrigerant bottle had a surrounding air temperature of 75°F, the pressure inside the bottle would be 217 PSIG. Using a PT chart or pressure temperature chart one can determine the pressure or the temperature of the refrigerant. However, keep in mind that the working pressure depends on factors like cooling load and weather. low side actual line temp on suction : 10 C. On 2018-05-26 by (mod) - I might look for a thermostatic expansion valve that is not closing when it should or is not correctly adjusted. Study with Quizlet and memorize flashcards containing terms like Because of its higher vapor heat capacity, the discharge temperature of R-410A is _____ than R22, Both suction and discharge pressures of R-410A systems are _____ than R-22 systems, The temperature glide for R-410A is less than _____ degrees Fahrenheit over air conditioning. Manifold Gauge Set – The high pressures encountered when working R-410A requires a manifold gauge set that has a low-side gauge that can read up to 500 PSIG and a high side gauge that can read up to 800 PSIG. 5°C) 86 psi R407C 118°F (48°C) 276 psi 46°F (7. Many conditions could apply here, there’s absolutely ‘no’ set point pressure for 410a, r22, or anything. The normal pressure for a typical R-401A mini-split ranges from 110-140 psi. However, if you rewind just fifteen or twenty years you would find that very little. R-22 and R-410A Operating Pressures, Charging and Recovery Setup! In this article, we will discuss an HVAC unit’s refrigerant pressure on both. "Manifold sets should be a minimum 700 psig on the high side and minimum 180 psig low side, with 550-psig low-sided retard. (also known as high side pressure or head pressure). Target condensing temperature / High Pressure Target evaporating temperature / Low Pressure R22 115°F (46°C) 261 psi 42°F (5. Usually, the high side pressure of an R410A mini split is between 230-300 psi. What is the average pressure a high pressure switch would open at for a 4ton rooftop package unit with r410a? Condensing temp used for rating efficiency is 105°F. Since R-410A operates at a higher pressure and a different type of oil is used than R-22 separate gauges should be used to obtain pressures. R-410A, or Puron, is one of the most popular refrigerants in today’s modern world. POE oils are compatible with R-410A. A normally operating R-410A system with the same condensing temperature of 120 degrees and a 45 degree evaporator saturation temperature will have a high side. Typical high side pressure for R410A is < 600 psi at an ambient outdoor temperature of 95. Discharge temps are ~55 degree, no icing. Digital Fieldpiece Gauges: https://amzn. What causes low side pressure to be 200 and high side pressure to be 250 on 410a. ( F) Liquid Vapor ( C) ( F) Liquid Vapor ( C) ( F) Liquid Vapor ( C) ( F) Liquid Vapor ( C)-49 5. The normal pressure for a typical R-401A mini-split ranges from 110-140 psi. The valve core I stock are light blue is OK for up to 1000 psi. The pressure generated on the output side of a gas compressor in a refrigeration or air conditioning system is known as discharge pressure (also known as high side pressure or head pressure). Improper operating pressures - too high: Refrigerant pressure will be increased on both the high side and low side of the system; More expensive operation: The system may still be able to change state, but at a higher temperature than intended, thus in an air conditioner, it won't cool as effectively nor as efficiently as with the proper charge. High suction line pressure in a 410a system? I'm currently being humbled by a 3 year old, 5 ton 410a system. The pressure of the refrigerant corresponds with the temperature. Many conditions could apply here, there's absolutely 'no' set point pressure for 410a, r22, or anything else. 1F + or minus Temp from supply side: 55. 1/4" female SAE mounting Automatic Reset Tamper proof 3A, 250VAC, 1 phase, SPST and 6A, 125VAC, 1 phase, SPST Low pressure switch - open on pressure drop, closes on pressure rise. How to adjust high side pressure on 410a HVAC system? 5. R-410A, or Puron, is one of the most popular refrigerants in today’s modern world. Normally R-22 operating system typically have a high-side (discharge) pressure of 260 psig and low-side (suction) pressure of 76 psig, while a normally R-410A operating system have a high-side (discharge) pressure of 418 psig and low-side (suction) pressure of 130 psig at 45°F/7. What is the normal high side pressure for 410a HVAC system? 3. A normally operating R-410A system with the same condensing temperature of 120 degrees and a 45 degree evaporator saturation temperature will have a high side pressure of 418 psig and a low side pressure of 130 psig. Your low side won't be running at 200 psi. Example of actual air conditioner compressor high side output pressure: Using R-22 refrigerant and assuming an outside air temperature of 85 °F called for 120 °F inside the compressor (add 35 °F to incoming air. It is important to know the range of these pressures in order to understand why and how charging and recovery are performed. Valve cores have differrent pressure ratings, It's not a one size fits all applications. to/2xv6AG5My Favorite Tool: https://amzn. Educate yourself on whats going on in the heat transfer process. Let's go with 20 degrees over ambient as a basic reference for this example: you should be seeing saturated condensing temps of 105°F, with a corresponding R410A. 6 times that of similar systems operating on R22. In the example of an R-410A packaged unit with a surrounding air temperature of 75°F, the pressure on both the high and low-pressure side of the. R-22 and R-410A Operating Pressures, Charging and Recovery Setup! In this article, we will discuss an HVAC unit's refrigerant pressure on both the high side and the low-pressure side while the system runs. r410a high/low pressures Residential 410a system as follows: Liquid line: ~400psi ~ 30 subcool Vapor line: 105psi ~30 superheat The LLFD does not feel cold. What are normal operating pressures for 410A in cooling mode?. When the heat pump is running it blows semi-warm air like it is operating correctly but when I put my gauges on the system the high side pressure was 425 and low side was 395-400. R-410 refrigerant operates at a higher pressure than R-22. The high side has an even greater range. R-410 refrigerant operates at a higher pressure than R-22. “Manifold sets should be a minimum 700 psig on the high side and minimum 180 psig low side, with 550-psig low-sided retard. Intro What Should my AC Pressures Be for R410A Refrigerant Benjamin Sahlstrom 376K subscribers Subscribe 5. r-410a pressure temperature chart psig f° psig f° psig f° psig f° psig f° psig f° 12 -37. Called my installer back out and the low side pressure was 150-175 and the high side was 500-800 with some clicking and relief squealing going on (funny noise). R-410A, or Puron, is one of the most popular refrigerants in today’s modern world. lets say i have a freshly vacuum unit i need to. Called my installer back out and the low side pressure was 150-175 and the high side was 500-800 with some clicking and relief squealing going on (funny noise). The gauge will have a pressure reading in pounds per square inch gauge (PSIG) and a R-410 refrigerant saturation temperature measured in degrees Fahrenheit (F). In the example of an R-410A packaged unit with a surrounding air temperature of 75°F, the pressure on both the high and low-pressure side of the system will be 217 PSIG. R-410A is currently being phased in for residential use as the phase period for R-22 draws nearer. This is significantly higher than a standard manifold set. 99 SuperCool Slide Rule by SuperCool Slide Rule $19. When the heat pump is running it blows semi-warm air like it is operating correctly but when I put my gauges on the system the high side pressure was 425 and low side was 395-400. With this higher pressure from 410A comes a need for new tools. A normally operating R-410A system with the same condensing temperature of 120 degrees and a 45 degree evaporator saturation temperature will have a high side pressure of 418 psig and a low side pressure of 130 psig. R410A REFRIGERANT PRESSURE / TEMPERATURE CHARTS [Web Article. to/3NIFJuOTools We Recommend: https:. My heat pump using R410A the low side is 202 psi and the high side is 550psi is this correct the outside temp is 80. The pressure generated on the output side of a gas compressor in a refrigeration or air conditioning system is known as discharge pressure (also known as high side pressure or head pressure). Normal R-22 systems operate with high pressure of about 260 psi at 120° temperature and low pressure of about 76 psi at 45° evaporator temperature. Typical high side pressure for R410A is < 600 psi at an ambient outdoor temperature of 95 °F,may vary by equipment What are the correct pressures for R410A? Suction pressure of an Air-Conditioner with R410A Refrigerants typically ranges between 115 Psig to 125 Psig when operated at an ambient temperature of 35 degC. Study with Quizlet and memorize flashcards containing terms like Because of its higher vapor heat capacity, the discharge temperature of R-410A is _____ than R22, Both suction and discharge pressures of R-410A systems are _____ than R-22 systems, The temperature glide for R-410A is less than _____ degrees Fahrenheit over air conditioning and refrigerating operating ranges and more. R410a suction pressure may be around 120psi, and R410a head pressure may be anywhere from 225psi to 350psi. The differences between these two refrigerants come down to the pressure level, their chemical composition, and their efficiency. 1 high side line temp. Improper operating pressures - too high: Refrigerant pressure will be increased on both the high side and low side of the system More expensive operation: The system may still be able to change state, but at a higher temperature than intended, thus in an air conditioner, it won't cool as effectively nor as efficiently as with the proper charge. In Ask an Expert Home Improvement Questions HVAC Questions HVAC Technician: Phil, mechanical engineer Category: HVAC 12,932 ___. What is the r410a’s suction and discharge pressure? A high-efficiency condensing unit with R-22, for example, typically operates at a 95°F outdoor temperature with a suction pressure of about 68 psi and a discharge pressure of about 250 psi. When you have an R-410a heat pump, I understand that in A/C mode the indoor coil is the evaporator and that the smaller copper line is liquid/high pressure and. Temp (°F) Pressure Temp (°C) Temp (°F) Pressure Temp (°C) Temp (°F) Temp (°C) Pressure Temp (°F) Pressure Temp (°C). r-410a pressure problem, 285/120 psig. or clogged or crimpled capillary tube, or having lost power to a TXV power head can cause high pressure and can also cause valve damage by flooding the compressor if instead the valve sticks wide open. The first thing to realize is that when a system is off and equalized, the system's pressures on both the high side and the low-pressure side will match. In other words, refrigerant gas returns to the compressor through the suction line from the cooling coil (which is cooling building air). If you Google "operating pressures for R-410a" you will get 420 psi for the high side, assuming the air coming off the condenser is 120 F. 5 ton condenser, 2 ton evaporator, and a 0. If you Google "operating pressures for R-410a" you will get 420 psi for the high side, assuming the air coming off the condenser is 120 F. Put my gauges on and got the following: 180 suction line pressure 320 discharge 10 degree temp split. However, the maximum high side pressure could go up to about 320 psi, especially in hot and. R-134A replaced R-12 for automobile air conditioning systems. R410A PT Chart: -60°F To +155°F Pressure Temperature Chart. However, the maximum high side pressure could go up to about 320 psi, especially in hot and humid countries. A normally operating R-410A system with the same condensation temperature of 120 degrees and a 45 degree evaporator saturation temperature will have a high side pressure of 418 psig and a low side pressure of 130 psig. Most contractors and technicians worked with R-22 systems for home and commercial air conditioning. So, when it is in heat mode, that is reversed -- but are the pressures also reversed?. What it the temp of the air coming off yours? Maybe your condensing unit has such an effective fan system that it cools the condenser better than the average fan. Manifold Gauge Set – The high pressures encountered when working R-410A requires a manifold gauge set that has a low-side gauge that can read up to 500 PSIG and a high side gauge that can read up to 800 PSIG. R-410A is currently being phased in for residential use as the phase period for R-22 draws nearer. Pressures are 120headover 118 suction low side. Let's take a look: Manifold Gauge Set - The high pressures encountered when working R-410A requires a manifold gauge set that has a low-side gauge that can read up to 500 PSIG and a high side gauge that can read up to 800 PSIG. This is significantly higher than a standard. external temperature is approx 40 deg F, would the maximum pressure not running be 190 psi then?low side 75 Answer Summary As with any refrigerant it depends on the ambient temperature. the problem is that the units are not cooling at all ( thermostat set at 16-18C and room temp stays at 30-31C the other day i took the following reading on a 4 ton ac unit high side pressure : 250 psi high side actual line temp near the indoor unit : 25 C low side 150 psi low side actual line temp on suction : 10 C. the problem is that the units are not cooling at all ( thermostat set at 16-18C and room temp stays at 30-31C the other day i took the following reading on a 4 ton ac unit high side pressure : 250 psi high side actual line temp near the indoor unit : 25 C low side 150 psi low side actual line temp on suction : 10 C. The normal pressure for a typical R-401A mini-split ranges from 110-140 psi. Question Summary What pressure should a R410 split unit operate at yes Thanks Bart Jay, it had a leak, but thats been rectified, and evacuated. r-410a pressure problem, 285/120 psig. Get it up to 200 and it would be grossly overcharged. 2F Temp for return side: 68F When I figure super heat or sub cool on these saturation temps and line temps my super cool/sub cool show I guess a major overcharge. Systems operating on R410A run at a pressure of about 1. It was installed on a 100k BTU furnace that is over 25 years old. Typical high side pressure for R410A is < 600 psi at an ambient outdoor temperature of 95 °F,may vary by equipment What are the correct pressures for R410A? Suction pressure of an Air-Conditioner with R410A Refrigerants typically ranges between 115 Psig to 125 Psig when operated at an ambient temperature of 35 degC. Energy efficiency is comparable to R22. When you have an R-410a heat pump, I understand that in A/C mode the indoor coil is the evaporator and that the smaller copper line is liquid/high pressure and the larger line is vapor. Presostats High & Low Pressure Switches for R22 and R410a Everwell Add to Wishlist Compare Features: SPST switch. There can be that delay as well. Manifold high side gauge for R410a refrigerant must range to: 800 psig Service hoses used with R410a equipment must range to: 800 psig Manifold low side gauge for R410a refrigerant must range to: 250 psig with 550 psig retard When handling Refrigerants, Technicians should? Wear approved eye protection and gloves. Compressor amps: high Low-side (evaporating) pressure (psig): 8. Advertisement Step 8 Purge the low-pressure, left-hand side hose for one second. Saturation Pressure-Temperature Data for R410A (psig)* Temp (°F) Pressure Temp (°C) Temp (°F) Pressure Temp (°C) Temp (°F) Temp (°C) Pressure Temp (°F. Does this indicate a LL restriction or some other cause? What would be the best way to determine the. What are normal operating pressures for 410A in cooling mode?. Digital Fieldpiece Gauges: https://amzn. r-410a pressure problem, 285/120 psig. the problem is that the units are not cooling at all ( thermostat set at 16-18C and room temp stays at 30-31C the other day i took the following reading on a 4 ton ac unit high side pressure : 250 psi high side actual line temp near the indoor unit : 25 C low side 150 psi low side actual line temp on suction : 10 C. Using the same system of units solves so many problems and answers so many questions that get posted here. Better yet use a pressure gauge that reads in Pa/MPa. So most OEMs will have a high pressure switch trip of 425 or more. Manifold Gauge Set – The high pressures encountered when working R-410A requires a manifold gauge set that has a low-side.