Pressure Gauge Installation, Operation and Maintenance
WINTERS INSTRUMENTS
MANUFACTURER OF INDUSTRIAL INSTRUMENTATION
Winters Instruments is ISO 9001:2008 Registered
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Pressure Gauges
Operation and Maintenance of a Pressure Gauge
Inspection Frequency
The frequency of inspection is dependent on the severity of service and how critical the accuracy of the indicating pressure. The
inspection frequency can range from monthly to annual basis. To ensure the accuracy of your pressure readings, it is strongly
recommended that all pressure gauges be recalibrated and certied each year. Winters provides test certication that are
traceable to the National Institute of Standards and Technology (NIST).
Isolating Valves
It is recommended that isolating valves be
checking, recalibration or replacing without interruption to the process. The valves should be opened or closed slowly to avoid
sudden changes to pressure being applied to the gauge. It is recommended for systems that have an abrupt pressure surge at
start-up to close the valves during initial start-up. Winters carries various types of valves.
Materials
Brass wetted parts are suitable for use on the following types of media: air, oil, water and other non-corrosive uids. For
corrosive fluids, stainless steel should be specified. For special applications, other materials such as Monel
well. Diaphragm seals may also be considered. Please consult for assistance.
Pulsation
If pressures are expected to pulsate violently, oscillate with high frequency or occur with sudden shock, a snubber should be
considered. Winters snubbers incorporate a sintered porous 316 stainless steel snubbing element with a large surface area to
ensure long term eectiveness on most pressure media. Snubbers are available in three viscosity classications: heavy oil,
water and air. Brass, stainless steel or Monel® housing can be specied depending on the media used.
tted with the gauge. This enables the gauge to be removed at any time for
®
can be used as
Storage
All pressure gauges should be placed in dry storage under ambient room temperatures. It is recommended to store pressure
gauges in their original packing boxes.
Temperatures
The normal ambient temperature ranges are -40°C to 120°C (-40°F to 250°F) for dry gauges and -20°C to 65°C (-4°F to 150°F)
for glycerin lled gauges. Process temperature up to 400°C (752°F) can be accommodated when a gauge is dry AND
appropriate external cooling is applied. In situations where the process temperature is extreme, utilizing a syphon or remote
mounting the pressure gauge with a capillary and diaphragm seal are reasonable alternatives. In general, a gauge is unduly hot
if it cannot be grasped by hand without discomfort. It should be noted that gauges used on water might burst if exposed to frost.
Vibration
Vibration can aect the dial reading of pressure gauges. These areas should be avoided as much as possible. Vibration eects
can be minimized by the use of a dampening liquid such as glycerin or silicone. If vibration is extreme, then a exible tube
connected to an appropriate diaphragm seal should be considered. A Winters StabiliZR™ movement can also be used to
improve dial reading.
®
Monel
is a registered trademark of Inco Alloys International
WINTERS INSTRUMENTS
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Pressure Gauges
Installation of a Pressure Gauge
Location
Vibration and extreme ambient temperatures can aect the dial reading of the pressure gauge. These areas should be avoided
as much as possible.
Mounting
A suitable thread sealant is required for NPT threads such as pipe dope or PTFE tape. The gauge should only be installed by
hand until the rst 2 threads engage. This will allow the gauge socket thread to be seated correctly. An open ended wrench
should then be used on the socket ats to tighten the gauge . DO NOT tighten the gauge by hand, otherwise it will severely
damage the gauge.
Venting Procedures
Due to pressure build up, some gauges (usually lower pressure ranges such as vacuum, up to 100 psi) may reect a reading
that is slightly “o zero”. To properly “vent” the pressure gauge, cut o the tip of the ll plug after you have installed the
instrument. This allows the gauge to be equal to the atmospheric pressure. Venting can also be achieved by lifting the stainless
steel or brass vent plug for a moment and re-seating (closing) it. In either case, the gauge should be installed in an upright
position to avoid the liquid from leaking.
Cut
Recalibration Procedures
Inspect the pressure gauge for “zero reading” when there is no applied pressure. In many cases, the gauge pointer can simply
be adjusted for the gauge to work within specications. However, if the gauge requires calibration, then follow the procedures
below*.
1. Remove the ring and lens
2. Slowly pressurize the gauge to its full scale and slowly release the pressure back down to zero
3. Check the gauge at a minimum of four equal pressure intervals against a certied test gauge*
4. Adjust the movement accordingly by removing the pointer with a pointer extractor. Be careful not to bend the pointer shaft
5. Remove the dial plate by loosening the holding screws
6. When adjustments are completed, replace the dial plate and pointer
7. Re-check the gauge for accuracy
8. Check lens assembly gasket for any deformation, tears or cracks. If there are any visual defects, contact Winters to get a
replacement gasket
9. Re-assemble the lens assembly
*Winters can recalibrate and provide test certicates that are traceable to NIST
Replacing The Lens
To replace a broken lens, check to see if the lens is held on by a bayonet or snap-on ring. To remove a bayonet ring, unscrew
using a rubber belt wrench. To remove a snap-on ring, remove any screws holding the ring in place then pry o the ring with a
small screwdriver. Remove all glass chips, insert new lens and re-insert the bayonet or snap-on ring. With snap-on rings, locate
the ring joint at the bottom of the gauge. Crimp-on rings cannot be replaced once removed. If you would like to replace the lens
or remove/replace crimp-on rings, please contact.
Replacing The Pointer
Remove the bayonet or snap-on ring as previously described above. Remove old pointer with pointer extractor or two small
screwdrivers opposite each other under pointer hub. Pry o evenly, being careful not to bend the pointer shaft. Install the new
pointer on zero. NOTE: Gauges with a zero stop pin must have the pointer set at a reference pressure (preferable mid-scale) to
oset the preload against the stop pin. Re-install the lens.
Note: When selecting a pressure gauge, always refer to ASME B40.100 (2013)
WINTERS INSTRUMENTS
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www.GlobalTestSupply.com
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