Originally had the same conditions above and came to the conclusion that the evap coil had blockage (we tried several times to clear it) and then removed all the refrigerant, swapped out the evap coil (used nitrogen while brazing), did a pressure test and vacuum test, and recharged with new refrigerant -- note: evap coil uses a piston metering device and we reinstalled the same one -- during the beginning of the recharging process the pressures and temps seemed to be ok but then the hissing noise at the condenser (bypass) started and after a few minutes the head pressure climbed way up and the suction did not follow -- but after we shut off the unit the head remained high and the suction followed -- after a few more minutes the head pressure dropped and the suction pressure remained high -- if the unit is powered back on then the cycle repeats itself -- so we're not sure what to check from here -- I suspected the condensing unit filter/dryer but the temps on either side of the device are not drastic
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Hello, typiccally with noncondensables in the system your head pressure would be alot higher. 175 is pretty low high side pressure. Usually coils will freeze due to either low airflow or low refrigersmt charge not becuase of non condensables. I would get a second opinion from a differant company.
Your head pressure is a little high, depending on the ambient temp and your suction pressure is a little low. The suction pressure should be around 68 psig, the equivalent of a 40 degree coil. You can try adding a little refrigerant, check your compressor amp draw. If head pressure keeps going up and suction doesn't come up you may have a restricted metering device or filter dryer
Hello take a evap coil split (return temp vs supply temp) 18*F would be great.If it is lousy the TXV valve is restricting the flow of freon or the filter drier is clogging.Adding freon will overcharge the system and the suction will NOT improve.
These numbers are a little high depsite the high ambient conditions.Amazingly enough ,automotive low side suction pressure will equal the degrees its putting out at the evaporator coil...for instance,70 psi low side pressure will produce about 70 degrees of cooling. At 300 psi on the high side(which is high) this is about as low as the suction pressure will go....you need it to go lower.I would probably be concerned with the freon level as a slight overcharge could boost these numbers.Poor air flow through the condenser can also create a higher head pressure than desired.If possible,I would evacuate and re-charge the system with the correct amount of 134a refrigerant. Try to get those pressures lower...about 250/50 would be a decent pressure value in this ambient condition.Verify good airflow through the coils and pay close attention to any foreign debris like plastic grocery bags or wrappers covering the coils...Ive even seen these make their way between the small gap between the condenser and radiator so use a light and inspect carefully for this.Air flow through that condenser coil is vital and any deficit there will create high head pressure which obviously causes high suction pressures....good luck
Hey there. First question I have is if you have a heat pump or straight ac. Straight ac is easy to diagnose. Your suction pressure will be high, your head pressure will be lower, not sure how clean your condenser coils are so its hard to say how high. Your amp draw on your compressor will be lower than normal. Also, when looking at the suction pressures, you have to keep in mind what temp the air hitting the evap coil is. If it is warm, that will make your suction pressure go up. Another way to check the vavles is to hold the suction line at the compressor when you shut it off. If the temp goes up the second you shut it off, this tells you the hot gas is leaking through your suction valves. You can also try to pump the system down, then shut it off and see how fast the pressure builds back up, this will give you and idea how fast it is leaking through. Let me know if you need any thing else, I'll be here. seth
Before you start checking pressures, you need to make sure that the unit is clean inside and out. You also need to know what the ambient temp is outside so you know what the pressures should read. Without this information, your info is useless to me. You need to know what your saturation temp is to determine if the head pressure is too high or too low. If the outside unit is dirty, you will have a high head pressure and low suction pressure. If the inside is dirty, you will have a high suction and a normal to low head. My advice to you is to clean first and then start checking temps and pressures. Otherwise you are spinning your wheels.