We carry a full range of pressure gauges for your kiln or furnace.
Diaphragm gauges are more sensitive and delicate.
Depending on the location of the gauge, you will get one of these types of readings all of which can be different. Gauge Pressure varies depending on orifice size. It is a reference number only and does not actually measure flow. Manifold pressure is the pressure used to determine orifice sizing and BTU output. The only device that can accurately measure gas flow is a flow meter.