Many possible reasons may lead to off zero of a pressure gauge:
1. Internal pressure
Due to changes in temperature and altitude, there may keep pressure inside the pressure gauges (especially for low pressure gauges). In this case, simply pull out the oil plug or tip to release internal pressure.
2. Overpressure
Full scale pressure range should be 1.5 to 2 multiple the normal working pressure. Bourdon tube will be overstressed due to overpressure.
3. Clogging
Process media with high density will always stuck up a pressure gauge. Please use diaphragm seal (our
P700 series) to prevent problem of clogging.
4. Mishandling
Gauges may be accidently damaged during transportation. Being crashed or rudely treated, it may become malfunctioned.