If your AC and heater visual, electrical and leak inspections don't turn up any problems,
save time by hooking up the manifold gauge set before you make the performance test. If
you find a leak and can correct it easily by tightening a connection, do so. But if too much
refrigerant leaked out, you may have to add some refrigerant to the system for an
effective performance test. We will get into detail on troubleshooting with gauges after
we explain manifold gauge set installation and adding refrigerant.
Manifold Gauge Set Installation
Never hook up the gauge set when the engine and air conditioner
are running. Be sure all the valves on the manifold are closed all
the way (turn them clockwise). Check the hose connections on the
manifold for tightness.
Locate the low and high side system service fittings and remove their protective caps.
Position or hang the manifold gauge set in a convenient location. Figure 8-2 illustrates a
good example of manifold gauge set hookup in one service situation.
A typical manifold gauge set hookup
is shown in this illustration. The center
hose on the gauge set is connected to
the vacuum pump.
The manifold gauge set is a necessary tool in troubleshooting AC system problems. The
following steps are performed during and after installing the manifold gauge set:
1. Purging Air from the Gauge Set Hoses
2. Adding Refrigerant to the System
3. Stabilizing the AC System.