R-22 and R-410a Refrigerant: Why the Vapor Gauge Pressure is too Low in Air Conditioning!

[Music] hey guys this is AC service ii today we're going over is on air conditioning systems with r22 and are for tonight why is the pressure so low on the low side gauge so this gauge right here is talking about the evaporator coil in cooling mode and this is also referred to as the vapor side suction side or low side so if you see a pressure for r22 that's lower than sixty PSIG where for r410a and it's lower than 105 PSIG you're entering into where if you look at our for tonight's the pink inner ring you're entering into where it's below 32 degrees and that's not a good thing for the evaporator coil likewise if it's below 60 psi G say it's like 57 56 you're below freezing for your r22 so you have late green for r22 is a saturated temperature now what causes that you could have a block filter drier you could have a liquid line restriction right before your thermostatic expansion valve or your piston it could be your screen right here see that I don't know if you can make that out very well to be your screen it could be the it could be the distributor tubing it could be the thermostatic expansion valve itself all right it could be any of those items so you can have a restriction somewhere in the liquid line before it actually gets to the evaporator coil now the other thing it could be it could just be low on refrigerant charge right so if you add refrigerant and you are not getting this pressure to rise if it's r22 or if it's r410a you're not able to get this pressure to rise but all it's happening is on this side the pressure keeps increasing and the actual saturated temperature may be Falls you're widening the gap and you're increasing the sub cooling which means you're adding refrigerant to the system you're increasing the sub point but you're not able to increase this pressure then then that's not a system that's low on refrigerant that's a system where you have maybe a liquid line restriction or a air blockage all right so you have some type of blockage in the air distribution system so say it could be dust on the bottom of the evaporator coil or on the return side of the evaporator coil you could have a dirty filter you could have a possible second filter somewhere that you weren't aware of maybe you know there's two filters that are in series in the ductwork for some reason maybe the homeowner installed another one and never realized there was one in there I've seen that multiple times you could have the duct is collapsing in on itself you could have that acoustical liner maybe coming apart and just clogging the duct you could have maybe the ductwork is not sized properly maybe the ductwork is too small so maybe if the pressure is is here and you have the correct refrigerant charge and you have 18 to 21 degree temperature difference but over time after maybe half an hour you know the pressure starts decreasing even lower then that would be an indication of a small duck either either an undersized return or an undersized supply maybe you have some of the supply registers are shut and cooling mode or some other type of air blockage all right so so that is some of the things that could be occurring if you see a low pressure now it could be that your low and refrigerant and in that case you want to try to find where the leak is coming from maybe it's even possibly from multiple text connecting and disconnecting engage sets or what have you it could be a coming out of the service board or maybe one of the teflon seals or in worst case it's when you have some type of braze joint or crack in the tubing somewhere or they had to pump down the unit fix the leak nitrogen theft vacuum pump and then release the refrigerant back into the system or if it's something where you're able to just tighten the nut down a little bit harder where the teflon seal was or something along those lines once you start the unit back up and after five to ten minutes you're checking the refrigerant charge again and you're able to add the refrigerant into the low side then the low side will then end up climbing as well as the high side while you're charging the system okay so it could just be that you're low on refrigerant but once again if you add refrigerant to a system say that at 105 psig well maybe it's at 100 psi G or 95 psi G you're adding refrigerant to it and the only thing that's happening is the high side keeps increasing but the low side does not increase that's a telltale sign that it's not low on refrigerant and that you need to start doing some investigative work for more in-depth analysis of reading the gauge set go ahead and check out the playlist for that I hope you enjoyed yourself we'll see you next time AC service back channel you

Channel: AC Service Tech LLC

Views: 18,767

Keywords: acservicetech, repair, maintenance, how to, fix, hvac, hvacr, how do you, r22 pressure gauge, r22 pressure readings, r22 pressure temperature chart, r22 pressure chart, r410a vs r22, r410a operating pressures, r410a charging procedures, 410a operating pressures, r410a low side pressure, refrigerant gauge pressure, read refrigerant gauge, read refrigerant manifold, freon pressure, low side pressure, suction pressure, superheat, subcooling, freezing, evaporator, evap, evap coil

Id: hFqd1dfHj_A

Length: 5min 14sec (314 seconds)

Published: Mon Apr 10 2017