A pressure gauge is a small instrument that protects expensive equipment. A wrongly selected or neglected gauge can show a misleading reading, hide a developing fault or fail without warning. This guide covers what to check when you select a pressure gauge and how to keep it accurate.
1. Select the correct pressure range
Choose a gauge whose range is about 1.5 to 2 times the normal working pressure, so that the pointer sits in the middle third of the dial during normal operation. A gauge that runs near full scale all the time ages quickly, and one with a very high range is hard to read accurately.
2. Pick a suitable dial size
- 63 mm (2.5 inch): compact panels and small machines.
- 100 mm (4 inch): the most common size for plants and workshops.
- 150 mm (6 inch) and larger: boiler houses and places where the gauge is read from a distance.
3. Decide on the case and liquid filling
Dry gauges
Fine for clean, stable pressure with little vibration, such as compressed air lines.
Glycerin-filled gauges
The liquid damps pointer vibration from pumps and compressors, lubricates the movement and protects it from moisture – ideal for hydraulic and pump applications.
Stainless steel cases
Preferred for corrosive atmospheres, outdoor use and wash-down areas.
4. Match the connection and the medium
Check the thread type and size (such as 1/4" or 1/2" BSP), and whether the connection is bottom or back mounted. For steam, a siphon (pigtail) protects the gauge from direct heat, and for aggressive media a diaphragm seal or suitable wetted material is needed.
5. Look for IBR certification where required
Boilers and steam piping in India fall under the Indian Boiler Regulations. For these applications use IBR-certified pressure gauges with the correct dial size and range as required by your inspector.
Simple maintenance routine
- Check the zero: with no pressure, the pointer should rest on the zero mark.
- Inspect regularly: look for a cracked glass, leaks, a bent pointer or a sticky reading.
- Protect from pulsation: use a snubber or needle valve if the pointer flutters.
- Use an isolation valve: it allows safe removal and replacement without stopping the line.
- Calibrate on schedule: compare against a master gauge at least once a year, or as your quality system requires.
- Never exceed the range: avoid pressure spikes above the maximum scale value.
When to replace a gauge
Replace the gauge if it does not return to zero, if the case is damaged, if it fails calibration, or if the dial has become unreadable. Replacing a low-cost gauge on time is always cheaper than an unplanned shutdown.
Need help selecting a gauge for a specific line? Send us the medium, working pressure and connection size and we will suggest the right model.
