The Fieldpiece Digital Vacuum Gauge, model SVG2, is a thermistor-based, standalone instrument that digitally measures a vacuum of 50 to 2000 microns. Used inline with your vacuum pump, the SVG2 measures the deep vacuum required to evacuate systems of moisture and other contaminants. The LCD display provides a pump down indicator showing progress from atmospheric pressure. It features an ergonomic design with a ruggedized rubber boot, as well as high and low alarms with visual and audio indicators. The sensor is designed to withstand pressures up to 500 psi (3400kPa) so that no damage to the SVG2 will occur when exposed to full system pressures.

How Does it Work? 
The SVG2 allows you to measure a deep vacuum when evacuating a system, removing all contaminants (mainly moisture). The alarm can be set for either a high or low target and has both audio and visual indicators. The alarm target is displayed in the lower screen when you press the SET button. The ALM button toggles between Hi alarm, Lo alarm, and no alarm. The LCD also displays whether the target is a high or a low and has a low battery indicator. The SVG2 displays “OL” when reading is above 2000 microns.

Applications. 
Measure the vacuum on a refrigeration system when evacuating refrigerant. The digital readout shows even small drops in pressure. While target vacuum pressures vary, the technician typically wants a vacuum between 300 and 400 microns for small systems and 700 for large systems.

LCD Display. 
This meter is equipped with a dual-data display, main (upper) display displays the measurement of vacuum (in microns of mercury). The secondary (lower) display indicates the rate of change of the reading by using the following designations: 
 

	When the pressure is increasing, the LCD will flash at a frequency relative to the rate of pressure increase.
	When the pressure is decreasing, the LCD will blink at a frequency relative to the rate of pressure decrease.
	When the rate of change in pressure is zero or near zero, this display will appear without flashing.

Alarm function.

1. Press the ALM (alarm) key to toggle between the three different alarm settings, ALM Hi, ALM Lo and ALM Off.
2. In the ALM Off mode, press the SET key to display the target Hi or Lo alarm. Pressing the up and down arrows will change the target. Press the SET key again to exit to main display.
3. If the ALM Hi is activated, the meter will have an audible and visual alarm when the vacuum goes above the ALM Hi target. 
   If the ALM Lo is activated, the meter will have an audible and visual alarm when the vacuum goes below the ALM Lo target. 
   The frequency (tone) of the ALM Hi is higher than the ALM Lo.
4. Default ALM Hi and ALM Lo are 300 and 50 respectively.

The high vacuum pump procedure.

1. Follow all manufacturer’s evacuation procedures over those in this manual in regards to specifications on how to evacuate systems.
2. Note: larger systems may take much longer to reach the levels below and a different evacuation method might be preferred.
3. Pull vacuum with a low-vacuum pump (50 to 80 torr or 26 to 27 inches of mercury vacuum) and recover refrigerant as necessary.
4. Switch to a High vacuum pump.
5. Connect the SVG2 with the included “T” fitting between the vacuum pump and the system.
6. Set your target Lo alarm (typically in the 50 micron range).
7. Draw a vacuum on the system.
8. Once you have reached the low alarm, set your target Hi alarm (typically 300 microns).
9. Power off the vacuum pump and close valves. If it takes more than three minutes for the vacuum to reach 300 microns it is likely that the system is dry and evacuated.

Cleaning the Sensor. 
Drop isopropyl (rubbing) alcohol into the opening of the SVG2 sensor and pour it out. Leave the sensor opening uncovered long enough to completely evaporate all of the residual alcohol. Do not use an object such as a cotton swab to clean the sensor, you may cause damage to the sensor.

Battery check function. 
Battery check function: The % of the SVG2’s battery charge can be checked by holding down the SET button for one second. A small battery symbol is displayed on the LCD screen to indicate a low battery.

Competitive Advantages. 
There are many digital vacuum gauges on the market. Like every instrument we design, we made ours exclusively for HVAC/R field service. The sensor is very durable and holds up when exposed to full system pressures (up to 500 psi). It has a rugged rubber boot and our familiar ergonomic design that’s easy to hold without fatigue. It includes a magnet on the back of the meter so you can hang it right there on the system while pulling a vacuum. The LCD display is large and easy to read. The meter face and buttons are arranged for easy one handed operation.