A/C
Manifold Gauges, charge hoses & quick couplers:
Details
of what you need to test and recharge your A/C system
and how you can easily convert your R-12 gauge set to work with
R-134a air conditioning systems! |
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Automatic
A/C charging stations are great because they provide all the required tools
in one unit. However, you can easily and safely test, diagnose and recharge
any A/C system with a basic set of manifold gauges.
Here's
a close up look at manifold gauge sets and what you should be checking and
looking for. We've also provided details on the different charge hoses and
couplers.
Do
you have a set of old R-12 manifold gauges? We'll show you how you can easily
convert them to work with R-134a A/C systems. |
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A
Typical manifold gauge set for auto A/C service,
testing and recharging |
Pictured
here is a typical manifold gauge set that allows you to test, diagnose and
recharge any A/C system.
The
better quality gauge sets include an all brass manifold (as illustrated).
The sight glass is not necessary, but a nice option to let you monitor the
flow of refrigerant.
All
gauge sets will include a high (red) and low (blue) gauge with on-off controls
for each. The center hose connection is used to attach to a recovery station,
vacuum pump or refrigerant supply.
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Need
details on how to
rechrage
or retrofit any auto A/C system ?
Get the details for
diagnosing
all auto A/C systems. |
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| 'Compound'
Low Pressure Gauge with 'retard' |
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| Every
manifold gauge set will include a low side pressure gauge that is usually
blue. It's commonly referred to as a 'compound gauge'. That's because
the one gauge will provide both pressure and vacuum readings.
The
gauge shown on the left includes a scale for measuring vacuum in green. The
'retard' section is a safety; should this gauge come in contact with pressures
higher than 120 p.s.i., the 'retard' section prevents the excess pressure
from damaging the gauge. |
Gauges
not
reading Zero?
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| Also
note that most good quality gauges include a calibration screw (silver screw
just about the 'retard' section) that will allow you to 'reset' the gauge
to zero. Gauges will typically go out of calibrations when used frequently
or from vibration or 'shock'. |
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| Typical
A/C Manifold gauge - Charge hose connections |
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every gauge set will have a slightly different configuration where the charge
hoses connect.
The
charge hoses thread onto the connections provided. This particular gauge
set if for R-134a charge hoses (there is a difference!).
Additionally,
this particular set includes 'blank' or 'dummy' charge ports so that you
can connect your couplers for storage. The center hose also includes an
additional port (with a valve). This added port allows you to connect both
a vacuum pump and refrigerant supply at the same time.
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charge hoses are not the same! |
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Although
charge hoses for R-12 and R-134a manifold gauges sets 'look' and function
identical to each other, getting the proper threaded connection is
important.
Typical
A/C hose sets are color coded; RED for high pressure; BLUE for low pressure;
YELLOW for the 'common' supply or vacuum hose.
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| Hose
sets are usually available in various lengths from 36" all the way to 8 feet!
Although they all function the same, keep in mind that a lot of today's
automotive A/C systems work with a relatively small refrigerant charge.
Maintaining the exact charge can be critical.
If
you're working with long hoses, keep in mind that those hoses could be holding
2-4 oz. of refrigerant! That could effect your charge. |
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| Note
that when you take a closer look inside the hose connections, each hose includes
a sealing gasket. They are a must for a leak free connection.
Also
note that these particular hoses do NOT include a valve core depressor. If
you're connecting to a port on a charge manifold that has a valve core, you
will have to use a hose that includes a depressor. |
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Likewise,
if your charge hose does include a valve core depressor, and you're connecting
to ports where there are no valves to depress, the core depressors can be
eliminated. That will help to improve flow through the manifold and speed
up recovery and recharging of refrigerant or freon. |
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This
was probably one of the best books on recharging air conditioning that I
have seen...
