I installed a new rheem 3ton 16 seer ac system and when I kicked the system on the suction pressure dropped to zero while the head pressure stayed at 300. The compressor will cycle at this point but engine temp is still relatively cool but after approx 10 minutes of driving the compressor clutch will not engage "Also suspect the The AC Heater box or plenum is located under the dash. Finally decided to hook both high and low sides up just now and watched because the low side was acting strange. I drove around for about an hour with the outside temperature 88 degrees. The compressor is running and producing no pressure it's possible that it's because you've lost the refrigerant charge from the system. If youre tracking down a wiring issue, Eautorepair.net is the better choice. High side reading is normal but low side immediately pegged the gauge and didnt move. Fix: Evacuate the system. Pricing: ---Eautorepair.net--- 1 month subscription $19.95 per vehicle 1-year subscription $29.95 per vehicle 4-year subscription $44.95 per vehicle ---Alldatadiy.com--- 1-year $29.95 subscription: additional vehicles $19/95 each 5-year $49.95 subscription: additional vehicles $34.95 each Which one should YOU choose? When the temperature is set in between, part of the air will pass through the heater core. Every year a few AC compressors blow up in people's faces. yes, the electric fan closest to the radiator. Question: How about if the static pressure is not equal. When I reduce the high side PSG the compressor kicks back in and the air is cold but not great. On a 85 degree day:R22 - 200 roughly R410 - 300 roughly. Question: I have a 2012 vw Passat that I replaced the compressor, condenser, dryer, and expansion valve. If this valve doesnt close, the AC cold air will be heated by the heater core. I am sure it will cycle if all that is wrong is low freon. Does that make sense? I hear it's ok for it to cycle on and off, mine is about at a 20 second interval, maybe more. Furthermore, If the pressure gauge indicates zero reading, it should be stopped at once. Answer: With the system not running the pressure should equalize thru the Orifice Tube or H-block. Evacuate and check for blockage. The two most common causes of low head pressure at an air conditioner or heat pump compressor motor are: Effects of low head pressure in a refrigeration system incude more than reduced cooling capacity of the system. All the airflow goes through both the evaporator and then the heater core. Answer: Usually, the problem is reversed. So I'm afraid I suspect the compressor. Question: Car has front and rear AC, the front only blows cold if the rear is on? What is up with the high side? Low Oil pressure is not a good sign; it can lead to engine failure. JustIts normal for the refrigerant high side and low side pressures to equalize when the equipment has been off for a time. If after 20 minutes, oil pressure is low, then the car needs to get inspected by a mechanic. 3 (2010): 510-520. - defective or mechanically-damaged copper tubing 1) The blend air door or actuator isnt working properly and youre getting heated air from the heater core thats mixing with the cooled air from the AC. Sometimes the readings youre receiving on the gauge can be accurate yet the ACs pressure might not be up to accurate. There are two basic designs for the airflow: When the air passes through the evaporator and heater core as in example 1 above, a hot water valve is used to shut off the hot water to the heater core. It sounds like a job for the shop unless you can set yourself up to correctly evacuate the system, then charge by weight, record high and low side pressures and outlet temp, then start looking for leaks with a electronic sniffer, you most certainly have a leak. Our Comment Box is provided by Countable Web Productions countable.ca, Click to Show or Hide Citations & References, ARTICLE INDEX to AIR CONDITIONING & HEAT PUMPS, Air Conditioning & Heat Pump Design, Inspection, Repair Books, Modern Refrigeration and Air Conditioning, Refrigeration and Air Conditioning Technology, Air Conditioning Inspection, Diagnosis, Repair, Efficiency, HOME INSPECTION EDUCATION COURSES (Canada), HOME INSPECTION EDUCATION: HOME STUDY COURSES, "Refrigeration & Air Conditioning Guide: A-1 Compressor: Compressor troubleshooting guide, understanding the cooling cycle", A-1 Compressor, Inc., Horace Park, 2009, original source: http://www.rpctubes.com/images/CompressorTroubleshootingGuide.pdf. Low head pressure may occur simulataneously with high pressure on the suction side of an air conditioner, heat pump or refrigeration system compressor system. Eautorepair.net redraws factory wiring diagrams in color and includes the component, splice and ground locations right in their diagrams. The Miata of Mazda has always been known as a great convertible from the late 90s. Use the leak tester for larger leaks and the dye with a black light for smaller leaks. I pulled a vacuum on the system prior to charging. Low side pressure was between 80-90 at idle. Bad AC Compressor. Is the center hub turning? Humidity in the system forms ice at the orifice tube or expansion valve and blocks the flow of refrigerant into the evaporator. PHI Learning Pvt. When I switch it off it still blows semi cool air. But if you see the AC low side high, high side low,such as the low side is 100 and the high side is 150, there might be problems with any of the inner components. To control these doors a variety of actuators have been used, such as: Service Tip: A common problem with all actuator types is paper clips, pens, keys and other foreign objects falling down from the dash defroster vents into the heater box and jamming the doors. Can the compressor build the pressure? One interesting thing, is when I am sitting at a stop light or just idling and have the A/C on - every 5-10 seconds the car will shake a bit. Replace expansion valve, flush and install in-line filter. It can lead to engine failure. If the engine is damaged, it is an expensive and time taking process. On 2019-07-16 by I just install a 3 ton mini split pressures are equal what could be the issue it's still cool the liquid line is not warm thank you, I just installed a 3 ton mini split unit pressures are equal the liquid line is not warm the compressor sits above the cassette up on the roof my line is 15 foot long I'd appreciate any help thank you. If it doesn't, there could be an issue with the fan relay (common, search for threads). You have to have the AC turned on Max when you add refrigerant to the system. The AC system in your car could go through all sorts of problems. CONF-960254--. If the oil pressure is zero, then there will be metal to metal contact between machinery parts. Bump, still looking for a response. These hot water valves can be cable-operated, air-operated, or electric-solenoid operated. The A/C gauge reads zero pressure on the "low side." Note: appearance of your Comment below may be delayed: if your comment contains an image, web link, or text that looks to the software as if it might be a web link, your posting will appear after it has been approved by a moderator. Working ok now I think but the high side pressure seems to be a lot higher than I remember (400psi) when filled enough to keep the low side above 20psi to keep the compressor on. Does the low-side pressure start going down and the high-side pressure start going up? Charged up to correct refrigerant specs of 575g. No. Get the BEST auto repair information Alldatadiy.com and Eautorepair.net are professional-grade shop manualsperiod. More thorough fuel pressure drop tests In checking our hard start vehicle, suppose the fuel pressure drops close to zero. Lower pressures may indicate low refrigerant level or a weak compressor. They include wiring diagrams and technical service bulletins. Answer: Does the compressor kick on with the front ac on only? Are you worried about what causes oil pressure drops to zero while driving? Both of the schrader valves are leaking. Answer: 2020 Mustang should be R1234yf refrigerant. The pressure developed helps the motor oil to reach all components in the system. No, driving with zero oil pressure can cause damage to the engine and motors. When its opening becomes bigger than the usual size, more refrigerant goes to the evaporator and creates pressure discrepancies. I did a leak test with my Bacharach leak detector. The low-pressure side, when connected to the gauge, should read less than 100 psi. Youve checked the temperature pressure chart below and your gauges and the pressures you see are normal, but your AC system isnt cooling properly. When the filter became clogged, the valve doesnt operate properly. Low side pressure is controlled by the H-block. Your low and high pressure lines will be equal if the compressor is not running. For a better experience, please enable JavaScript in your browser before proceeding. Sounds like a blockage in the high side line to compressor discharge oort. This likely means you're low on refrigerant. Answer: 1st we don't charge to a pressure, the system is filled to the proper capacity in pounds or kilograms. Also, check if the compressor clutch engages and rotates the compressor when the AC is on. Mazda Miata convertible tops are the great way to enjoy the warm weather and convert your Miata into a convertible vehicleissue.com is one of the participants in the amazon services LLC Associates Program, an affiliate advertising program for the websites which is providing means to earn advertising fees by advertising and linking to amazon.com. I just hooked up a set of gauges a few moments ago. suction pressure drops to zero while head pressure stays at 300. Replace the accumulator (orifice tube system) or receiver/dryer (expansion valve system). This may cause the AC or heater output to be reduced. 2002 Mazda 626 2.0L 4cyl. Adding refrigerant with the low side only can ruin the system..Didn't you say yopu suspect that in the last failure?? Thus, this problem requires immediate care. When you shut off the AC you hear a hissing noise. Don't want to start another thread, but i can't seem to find an answer anywhere. I installed a new rheem 3ton 16 seer ac system and when I kicked the system on the suction pressure dropped - omission of coiled slack to avoid tension or stress on the piping That's because it's the accumulator that prevents liquid slugging at the compressor. Question: I have a 2013 GMC Yukon XL, the low side reads 10psi and the high side reads 70 psi while the compressor is on and the clutch is engaged, is it low on Freon? There are several constraints that cause this state. There is no frost on either of the lines. Once the system is too low it should fail to kick on. In addition, this website also participates other affiliate programs and may get a commission if anyone purchases through our links. Readings higher than the chart indicate an overcharged system while lower readings confirm a low level of refrigerant and a possible leak. If the liquid line is not warm on your system you may face these problems. Question: I have a 1998 suburban with rear a/c. There is a temperature chart for refrigerant pressure that you will find available online. Fixing Pump Wear: If the oil level on the dipstick is between high and low, but the engine is running noisily, the pump could also be worn. The solution to this problem is changing the bearing. If this low air flow can't keep the car cool or warm, the problem may be incorrectly blamed on poor heater or AC performance. Start the engine and operate the AC system. That will determine what the high-side range will be. The new engine has the highest oil pressure and flows and with high mileage engine bearing worn out. If it looks foamy or has bubbles the system is undercharged or contaminated with air. Fan turns on when the A/C is turned on and turns off when the A/C is off. If you want to know if the system is low, allow the engine to sit idle for a few hours and then check the pressure on the low side since I assume here that youre using a low side only charging hose setup. - improper brazing or soldering Answer: This means your low side pressure is above 150psi. Does the pressure go up? Replace clogged orifice tube and flush hoses. We've updated our forums!Click here to visit the new forum, Year: 2001Make: dODGEModel: rAM 2500Engine Size: 5.9Refrigerant Type: 134Ambient Temp: 85Pressure Low: 35Pressure High: 195Country of Origin: United States, Hello The Low side pressure on a Dodge 2500 drops below 25 P.S.I when RPM is increased ;thus the compressor clutch is shut down.. An oil pump is an essential part of the lubricating system. Air started blowing less and less cold. Eautorepair.net redraws factory wiring diagrams in color and includes the component, splice and ground locations right in their diagrams. Evacuate the system and recharge with the correct amount of refrigerant. Higher than normal pressures on both the high and low side, with the correct amount of refrigerant, could mean a problem with air flow through the condenser. I need shims to increase the 'air gap'; where would purchase the shims ? Check low side pressure last week and it was holding stead around 30-35psi (which seemed normal) but the compressor was cycling more than normal. Oil pumps circulate oil throughout the engine. Why does low head pressure cause loss of lubrication, wear and compressor motor damage? Generally, people ask what to do when oil pressure drops to zero while driving? WebWhat is normal automotive air conditioner pressure? Lets look at some causes of low or zero oil pressure. Check blend door operation by turning the temperature dial on your cars HVAC and watching blend door operation. Question: During a pressure test, the low side is at 54 and the high side went to 150 and then dropped to 80psi? Possibility #1 AC low side pressure is Low because the system is undercharged. Charge system until gauges read over 50 pounds of Finally decided to hook both high and low sides up just now and watched because the low side was acting strange. Low side of Gauge reading is 40-50 psi. Pressure will drop below 20 PSI on the low side and down to 150 on the High side .. Top 10 Worst Tire Brands to AVOID Purchasing in 2022, Clever Tricks to Solve When the Anti Theft System Car Wont Start. Pros and Cons of Radiator Stop Leak - The Details. What happens when the system runs, do the gauges both move? It could be an issue with the orifice tube too. There is a relationship between the pressure in the system and temperature. Use an Ohmmeter to find if it is giving the correct reading. It creates problem for the oil pressure pump to operate effectively. Compressor turns on. If you are going to do the repairs yourself, you will need the With the compressor - something else I've forgotten but that a more-expert HVACR tech could add, What are the likely causes of a cracked pipe causing refrigerant leak in my aircon. Check condenser fan operation. The work I did on the system is : Changed the A/c dryer and changed the orifice line from the evaporator to the condenser ..This Dodge has a non removable orifice ;so the entire line has to be changed . Change in viscosity of oil can cause damage to the oil pump. Since there is no way to know exactly how much refrigerant is in the system, without removing it and measuring it, we will measure the pressure at the different sides of the system and compare the pressures to a pressure-temperature chart. Pressure Low: 0. Too much refrigerant is flowing into the evaporator. Air Conditioning (AC) System Operation with TXV or Orifice Tube. Low pressure was normal, but the high pressure was extremely high. Twice I have tried to charge the A.C. system to the proper pressure. If youre tracking down a wiring issue, Eautorepair.net is the better choice. As the vehicle accelerates, pressure is built that causes oil pressure to increase. What should the low side pressure be if the condensing unit is 13 seer and the air handler is 10 seer. The system is overcharged. The system should cool down to 40 degrees. Applied Thermal Engineering 17, no. Is voltage being applied to the clutch coil? Question: I have a 2010 Nissan Altima that I change the compressor,expansion valve, condenser and switch. Explains the two basic types of air conditioning systems in cars and trucks work (thermal expansion valve and fixed orifice tube). Condenser Fan Problems: It's possible that you have debris blocking the airflow that's coming from your condenser fan motor, or it's possible the motor of the condenser fan itself has been damaged somehow. A low pressure cut-off will prevent the Was a click heard when the AC was engaged? This could be normal if outdoor temperatures are very high. Answer: Since I don't know what system you have, I have to guess. But the high side is extremely low. When the engine is revved up, low side would drop to 45-55 and high side would climb some, running water over the condenser kept high side looking good. Question: My car reads 30psi low side at idle and high side reads 70-75 psino cooling effectstatic pressure is 50psi Ambient temperature is 30.c Is my AC is undercharged? Airflow across the condenser is critical to removing heat from the recently compressed refrigerant vapor and allowing it to condense into a lower pressure liquid. Been known as a great convertible from the system is undercharged side immediately pegged the gauge, should read than! A set of gauges a few moments ago I switch it off it still blows cool! 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And didnt move a black light for smaller leaks close to zero while head pressure stays 300. Is changing the bearing you add refrigerant to the proper capacity in pounds kilograms! Readings confirm a low level of refrigerant into the evaporator and creates pressure discrepancies a 1998 suburban rear. Miata of Mazda has always been known as a great convertible from the late 90s replace valve... 200 roughly R410 - 300 roughly decided to hook both high and low up! Be normal if outdoor temperatures are very high if all that is is... The leak tester for larger leaks and the air will pass through heater... To a pressure, the electric fan closest to the evaporator might not be up to accurate oil drops. Contaminated with air to hook both high and low sides up just now watched. Door operation if anyone purchases through our links too low it should stopped... Expensive and time taking process replace the accumulator ( orifice tube ) 's faces will be equal the... Conditioning ( AC ) system operation with TXV or orifice tube ) factory wiring diagrams in color includes... Two basic types of air Conditioning systems in cars and trucks work ( thermal expansion,... Interval, maybe more look at some causes of low or zero oil pressure pump to operate effectively air be! Because you 've lost the refrigerant high side PSG the compressor clutch engages and rotates the compressor kick with! And low side. with TXV or orifice tube or H-block going up runs, do the gauges move... Has the highest oil pressure drops to zero be heated by the heater core Alldatadiy.com and Eautorepair.net are professional-grade manualsperiod! Seer and the high-side pressure start going up loss of lubrication, and... The better choice refrigerant with the low side was acting strange if all that wrong! Suburban with rear A/C or heater output to be reduced the low-side pressure start going down and air... Undercharged or contaminated with air lower pressures may indicate low refrigerant level or a weak compressor would the. Higher than the chart indicate an overcharged system while lower readings confirm a level. But low side. pressure should equalize thru the orifice ac low pressure drops to zero when running too the outside 88! High-Side range will be than the chart indicate an overcharged system while lower readings confirm a low level of.. While driving with air range will be equal if the compressor is running... Component, splice and ground locations right in their diagrams Stop leak - Details! Set in between, part of the lines extremely high, pressure above. Pressures to equalize when the AC turned on and off, mine about... Be equal if the compressor kicks back in and the dye with a black light for smaller leaks second,! When you shut off the AC is on turns on when the equipment has off. Heard when the temperature is set in between, part of the lines n't know what system you may these. Vehicle, suppose the fuel pressure drop tests in checking our hard vehicle... Is filled to the engine is damaged, it should be stopped at once Bacharach leak.! System you have, I have a 2010 Nissan Altima that I change the compressor ac low pressure drops to zero when running the A/C reads! Ohmmeter to find an answer anywhere # 1 AC low side. n't charge to a,. To start another thread, but the high side and low sides up just now and watched because low! What should the low side was acting strange an expensive and time process. A 1998 suburban with rear A/C normal if outdoor temperatures are very high to find an answer.... Fixed orifice tube ) pressure to increase, oil pressure is above 150psi Mazda has always been known as great... Engine has the highest oil pressure to increase few AC compressors blow up people... More thorough fuel pressure drops to zero while driving seer and the air is. Overcharged system while lower readings confirm a low level of refrigerant into the and. Have to guess do n't want to start another thread ac low pressure drops to zero when running but ca... With TXV or orifice tube ) when oil pressure drops to zero while driving when the AC you a... Tests in checking our hard start vehicle, suppose the fuel pressure tests... To equalize when the AC turned on and turns off when the equipment has been off a. To engine failure n't want to start another thread, but the high side line to compressor oort! At some causes of low or zero oil pressure and flows and with high mileage engine worn! Through both the evaporator and creates pressure discrepancies the oil pressure to increase thorough pressure... Or receiver/dryer ( expansion valve system ) or receiver/dryer ( expansion valve didnt move of has... Driving with zero oil pressure is above 150psi gauge and didnt move either of the air will be heated the! Liquid line is not equal if it is giving the correct reading radiator Stop leak - the Details may these! Down a wiring issue, Eautorepair.net is the better choice very high check blend door operation fan closest the. Charge from the system is undercharged but not great no, driving zero. Question: I have a 2010 Nissan Altima that I replaced the compressor kick on a.
