& Refrigeration Systems (HVACR) Evacuation
The Importance of Measuring Vacuum
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Thermistor Vacuum Gauge
Robinair’s 14777 electronic vacuum
gauge is just 2-1/2" x 3" in size, but
accurate enough to clearly indicate when the system is
free from moisture and ready for recharging.
Specifically designed for use with a high vacuum
pump, the 14777 measures to 10 microns.
- Clearly Shows Vacuum Level
– The display is an
easy-to-read LCD type with readout showing
the current vacuum level.
6' Lead for Service Flexibility – Hang the gauge
in a location that’s convenient for you to
monitor vacuum level.
- Mounting Magnet – Position the 14777 where it’s
easy to read the LCD. -
The Importance of Measuring Vacuum:
Without a means of measurement, evacuation
time is based on guesswork. The length of time required for
thorough dehydration will vary from system to system because of
several factors – so using a clock isn’t foolproof. You risk not
removing all the moisture – or wasting time by running the pump
long after evacuation is complete.
Many service technicians rely on the compound
gauge of the Manifold
to read vacuum. While the manifold is good for gross
measurements, it’s simply not accurate enough to determine exact
vacuum levels. It’s designed to read low pressures in inches of
mercury, but there’s no way to read exact levels when you’re
pulling the last, most critical inch of vacuum.
If you look at the compound gauge face, you can
see that it’s not possible to clearly differentiate between 29"
Hg and 29.9" Hg, for example. But in microns – the precise
measurements for the last inch of vacuum – that’s the difference
between roughly 23,000 and 250 microns.
A closed-end, U-tube, mercury manometer is
capable of reading to 500 microns. However, it’s a delicate
instrument, more suited to a laboratory or controlled
The most economical, effective, and easy-to-use
option is an Electronic
Gauge. It eliminates the
guesswork by measuring the vacuum to precise micron levels,
ensuring the system is leak-free, moisture-free, and ready to be
recharged. Although originally developed as a laboratory
instrument, today’s thermistor vacuum gauges are rugged enough –
and reliable enough – for field service work.
in an A/C system is a serious problem for the technician –
it causes freeze-ups and corrosion, seriously damaging the A/C
system. The most effective way to eliminate moisture is to
create a vacuum deep enough to boil it away. For that, you need
a high Vacuum
Pump, and a tool to tell you when
the vacuum is deep enough to adequately dehydrate the system.
Refrigerant Charging Scales
Refrigerant Recovery Machines
Manifold Gauge Sets