Currently out of stock of all gauges. The USA gauges are a scaled down version of the fine old flanged case gauges used in the age of steam. It approximates 1 1/2" per foot and dresses up a boiler very nicely. Available in 4 pressure ranges. The gauges are calibrated on master gauges calibrated yearly to within 3% error. The exception to this is at the very upper range of the gauge, where because of geometric problems caused by the very small size of the gauge, we are not always able to maintain this tolerance. You should select a gauge such that when applied the normal pressure reading would be at 1/2 of the scale (e.g. not too low or high on the gauge, in the middle is best). Example would be a boiler running at 100# should have a 200# gauge installed. A siphon for the gauge is an absolute must (available in our online store) when used in steam service. The gauge is not designed for service where rapid pulsation in pressure is enchanted such as hydraulic service. Gauge is 1 1/4" diameter and is threaded 10-32.
