Utility and HVAC troubleshooters look to TPI for isolating difficult pressure problems on natural gas and propane systems. Replace messy U-Tube manometers and expensive pressure gauges with a TPI 600 series manometer. Test for leaks in low-pressure gas systems. All models provide accurate readings (basic accuracy of ±0.5% reading with a .01 inch resolution). 

Value added features of the 625
With dual inputs and selectable units of measure, you can connect to the inlet and outlet of a gas valve at the same time with one tester. Differential pressure readings as well as individual pressures can be viewed in any of the 7 units of measure desired by pressing the UNITS button.

Units of measurement for the 615 and 625 are mmHg, inHg, kPa, mbar, PSI, inH20, and mmH20. The 610 and 620 only measure in inches of water.