When the unit is running well, the low side and high side pressures 1/4 Charging Hoses will be as follows:
- Pressure will normally be in the range of 40 to 100 pounds on an r-22 system. Whether this is correct or incorrect can only be determined by the measurements of the Superheat and comparison of it to conditions of the indoor air (conditioned space) and the outside air (ambient).
If the indoor temperature 1/4″ standard colored hose at the time of measurements is above the 80 deg. F. then the superheat will be HIGHER. If the temperature indoors is below the 80°F. then the superheat will be LOWER. A 70°F. indoor with a 100°F. outside may be as low as 1 to 3°F superheat, for example. Additionally, you probably will not be measuring the wet bulb temperature and knowing the moisture level anyway. Use good judgment here and hope for the best guess multi-purpose charging set for A/C system. You won’t be too far off if you are using this superheat information. That is our aim.
If your system uses the thermostatic expansion valve (TXV) device versus the capillary tubes, then you have less difficulty determining the superheat, because they usually will be automatic in nature and will maintain a very consistent 5 to 15°F. superheat. Only when they are failing or other things like dirty evaporator coils or reduced airflow over the cooling coils exist do they allow incorrect or out-of-scale readings.