manufacturers color coded the exteriors of the HVAC gauge (compound gauge and high pressure gauge) to distinguish between high pressure and low pressure pressure gauge or compound gauge is color coded blue and the high pressure gauges are color coded red. Don’t confuse this with the manifold gaugesIt’s not color coded. The AC gauge hoses are color coded in blue, yellow, and red. gauge hoses port are not color coded, but the hose is color coded. hoses are used to connect the manifold to the low pressure side (central air color coded red mark the high pressure gauges and it’s connected to the air conditioner unit discharge valve or liquid line valves. color code the hand valves. manifold gauge uses flexible hoses with connector on both sides. are label with maximum pressure in PSI or bar. This mean that if someone used the wrong hoses with the wrong pressure it will burst. located in the left hand of HVAC gaugesThe compound gauge is mounted on the left side of the air conditioning gauges.

The compound gauges allow the HVAC technician to measure both pressure. atmospheric pressure and vacuum pressure (blow atmospheric pressure). what compound gauge looks like: gauge is a R-22 gauge (There is a R410A, 134A compound gauge).In this gauge we could . pressure scales are in black and in red number. The black numbers are above atmospheric pressure, which range from zero to 150 pounds per square inch gaugeHowever, I couldn’t label all of it, so we only see zero to 100 psi in pressure below atmospheric pressure is in red number and it’s read in inches ofThe below atmospheric pressure is measure from zero to 30 in. the actual compound gauge: conditioner gauges are a pressure and temperature charts in a gauges. read it the same way we read a pressure and temperature chart. every HVAC technician looks at gauges, he or she either looking for pressure orLet say we have R -22 refrigerants and the temperature is 33°F, but we don’t know the pressure.

used the pressure temperature chart or the manifold gauges to find out what is the pressure of R-22 refrigerant. That pressure would be 58.8 psi for R-22 sample of temperature and pressure chart in HVAC gauges: temperature and pressure charts above, the Temperature scales are on the left side and it’s in Fahrenheit or Celsius. On the right side we have the difference types of AC refrigerant pressure.Ex. HCFC-22 refrigerant has a pressure of 62.9 psi, what is the temperature of R-22The temperature would be 36 °F or 2.2 °C. valuable information about the manifold gauge set is it could read a pressure and temperature of refrigerant in a close system. All HVAC gauges set read theExcept the pressure and temperature scales are different for R-134, How to use HVAC manifold gauges videos Make sure to press the Play button in the player controls to watch it. Air conditioner gauges training Videos made by DrZarkloff pressure gauge is mounted on the right side of the manifold set.

This air conditioning gauges set measure pressure above theIt reads from 0 to 500 psi and it scales is usually in 2-lb. or 5-lb. increments. pressure gauge is label the same way as the compound (low pressure gauge), except we couldn’t read inches of mercury in high pressure gauge.uv light for ac home depot black number is the PSI scale and the inner number is the refrigerantac unit hissing sound temperature of R-502, R-22 and R-12. honda odyssey rear ac unit the actual high pressure gauges: field, we don’t have single set of HVAC gauges that work on every refrigerant. It saves us money and time if we have it. reason we don’t have single HVAC manifold gauge is because of the refrigerantEach air conditioner Freon has a difference pressure, chemical

compound, and boil points. However, that isn’t the main factor. refrigerant pressure and it temperatures scales. conditioning manifold gauge we carry:This means that we can’t use R - 22 gauges manifold to read an R - 410A refrigerant. It would damage the R- 22 gauge set due to high pressure of R 410 Return to central air conditioner and refrigeration There are many questions about air conditioner issues with the most common being that it isn't cooling properly. Among the typical answers are low Freon and the standard diagnosis for low Freon is ice on the large copper pipe at the outside compressor. From my understanding the small copper tube is the high pressure side with Freon that has been compressed to a liquid. When this liquid is allowed to boil in the inside evaporator things cool down. Conversely the large copper pipe is the return line from the evaporator sometimes referred to as the suction line or low pressure side. So my question is: under low Freon conditions how can the suction line freeze up?

Intuitively I would thing with low Freon the entire cooling ability would be below normal causing the evaporator to not produce as much cold air. A side effect of all this, I would expect the suction line to be warmer that normal. Why does the suction line freeze up under low Freon conditions? See the image in this question for a great diagram of an HVAC system: What's the most common cause of A/C refrigerant lines freezing? Chlorodifluoromethane, also known as R22 refrigerant has a boiling point of -40°F at 0 psi. As you increase the pressure of the refrigerant, the boiling point also increases. At 68.5 psi, the boiling point of R22 is 40°F. In a normally functioning system, the refrigerant is sent into the evaporator at about 55-65 psi. Which means that the boiling point will be above the freezing temperature of water. The refrigerant absorbs heat from the air passing through the evaporator, boils, and flows on down the line at a temperature above the freezing point of water.

The refrigerant will likely be below the dew point, however, so there will be condensation on the line. If the pressure in the system drops, the R22 might be entering the evaporator a bit lower than the typical pressure. In this case, the boiling point of the R22 will be below the freezing temperature of water. As the warm moist air moves over the evaporator, the moisture condenses and freezes on the coils. Ice will start to form at the beginning of the evaporator coils, and slowly creep along its length. The ice will act as an insulator, so the refrigerant in the line will not be able to absorb the heat it needs to boil. This causes the refrigerant to boil off further along in the evaporator, which forms more ice further down the line. This process continues all the way along the line, until the entire evaporator and suction line are covered in ice. Once the refrigerant levels get too low, there's not enough refrigerant in the system to freeze the line. So eventually if the system has a leak, this behavior will stop and you'll simply get no cooling at all from the system.