R134A AC System Pressure - How to Spot the Issues!

hey there I'm Robin and today we are taking a look under the hood at a simple and cost effective way of inspecting the AC system in your car pressure Diagnostics [Music] [Applause] [Music] now in order for an AC system to function flawlessly there needs to be proper refrigerant operating pressure testing the pressure is a great way to troubleshoot the AC system you can spot malfunctions in the system by simply seeing values of the pressure measured on either the high side or the low side having either LP or HP readings outside of its preferred range can mean there are a lot of potential problems that need to be found and taken care of typically the most common result of various AC system malfunctions is there not being enough cool air delivered into the vehicle's cabin the pressure diagnostic method is easy reliable and cost-effective only basic tools are needed such as pressure gauges and it works for most vehicles running on r134a gas so let's go take a look at the tools you'll need [Music] the tools you'll need include a pressure gauge manifold and a set of hoses or a service station that includes these and a refrigerant dedicated sharp showing the operation pressure valves measurements and indications in a given temperature you ready let's go take a look under the hood to start make sure the LP and HP gauges are correctly connected to the system respectively to the low and high pressure side service ports by means of the a/c service unit vacuum the hoses set to purge them from the atmospheric air before starting the test you have to make sure the system is in operational condition and this requires the correct level of refrigerant charge with at least 1.5 bar / 25 psi of static pressure to run the compressor to determine that static pressures of the system should be read before starting the engine the LP and HP pressure gauge indications should be close to equal on both sides remember if the static pressure is too low that means a low system charge and that there might be a leak that must be found and repaired the actual static pressure will depend on the ambient temperature to determine if it's correct refer to the static pressures table applicable for r134a after the static pressure test is passed operational pressures can be measured for reliable outcomes the vehicle must achieve its normal operating characteristics the engine must get started and idle the AC system must be set to produce maximum cold air and around 70 percent of the blow power must be set inside the cabin wait until the engine gets to its proper operating temperature of 80 to 90 degrees Celsius or 180 to 200 degrees Fahrenheit now you can determine possible failures by reading the operating pressures read the gauges indications and refer to a table with r134a operating pressure values for HP and LP and please remember the values will vary depending on the temperature in the room and the compressor type like if it's a fixed or variable displacement what we see here is a correct reading of the pressures the LP side is between one two three bars or ten 250 psi and the HP side is between 10 to 20 five bars or 142 350 psi and the static pressure reading before the test was also alright this means the system operates well but what else could be the case both the LP and the HP side will indicate pressure readings that are too high much higher than what is in the normal range for both sides a reading like this could typically mean that there is a system overcharge caused by too much refrigerant or too much additives dosed such as UV dye that there is improper compressor control such as ecv or MCV valve malfunction it can also indicate some flow restrictions on the HP side either by the receiver drier or within the condenser caused by bent tubes or impurities or it could mean that there is improper operation of the condenser including surface damages or excessive soiling disabling the unit function you will need to determine and eliminate the root causes and this will bring the pressure to the proper levels again as you can see this troubleshooting method is easy and effective to learn more about pressure scenarios and the potential issues related to improper ranges I recommend you get one of these posters issued by nYSSA's the poster contains a complete overview of possible scenarios and explains how to use the method you can get a free copy sent to your garage or digital version from their website that you can use on your PC or your phone just visit mrs. calm / climate I'm Robin and thanks for letting me show you what's under the hood [Music] [Applause] [Music]

Channel: Robin under the Hood

Views: 356,542

Keywords: r134a pressure chart, r134a recharge car, r134a recharge refrigerator, r134a ac system, refill r134a, recharge r134a, how to refill r134a, how to recharge r134a, how to recharge car ac, automotive a/c, charging car air conditioning, 134a, a/c, air conditioning freon, fixing automotive air, r12, checking air conditioning, robin under the hood, ac system pressure too high, ac system pressure diagnosis, ac system pressure chart, pressure wrong in car, climate system pressure

Id: _Qt6UCmzRH4

Length: 4min 58sec (298 seconds)

Published: Thu May 02 2019