Analog manifolds have a blue compound gauge for the low side and a red pressure gauge for the high side, with hoses and valves for charging, recovery and evacuation. Digital manifolds add built-in PT charts, temperature clamps and live superheat and subcooling. Every connection loses a little refrigerant and risks contamination, so careful techs connect gauges for a reason, not by habit.
Don't throw gauges on it yet, check the filter, the coil and the split first, nine times out of ten it's airflow.
Hearing put the gauges on it as the first move on a no-cool call marks a beginner; airflow comes first.
Also heard as
- manifold
- manifold gauges
- gauge set
Related terms
High side
The high-pressure half of a refrigeration system, from compressor discharge through condenser to the metering device.
PT chart
Pressure-temperature chart: a table giving each refrigerant's saturation temperature at each pressure.
Schrader valve
A spring-loaded valve core in a refrigerant service port, opened by the depressor in a gauge hose fitting.
Micron gauge
An electronic vacuum gauge that reads very low absolute pressure in microns of mercury during evacuation.