Frequently Asked Questions (FAQs)


Find answers to the most commonly asked questions concerning terminology, application support and ordering information for pressure gauges, pressure transmitters and transducers, and diaphragm seals.


Pressure Gauges


Pressure Transmitters & Transducers


Diaphragm Seals


Pressure Gauges


How do I choose the right liquid for a filled gauge?

The type of liquid used to fill the gauge varies with the application. Although pure glycerine provides the best performance in most applications, each has its own requirements. Guidelines to help ensure that a fluid is properly matched to an application are:


  • If icing is a problem, use gauges filled with silicone oil or other comparable liquids. They have low viscosities even at -60°C.
  • If the system has electric accessories, such as contacts, use insulating oils.
  • If extreme temperature fluctuations are expected, use silicone oils. The higher the liquid viscosity, the greater its dampening capacity. The reason for this is that dampening changes in proportion to the temperature-dependent viscosity of the filling liquid. The suitable degree of dampening depends on the operating requirements the gauge must meet, such as pointer response time, pressure extremes, vibration and changes in pressure. WIKA can recommend specific liquids to suit problem applications.

How do I vent a liquid-filled gauge?

To vent a WIKA liquid-filled gauge, move the valve to the open position which will release any pressure or vacuum built up in the case. If the gauge is installed in an upright position, the lever can be left in the open position (the lever allows use of the gauge in a non-upright position).


What are the advantages of a liquid filled gauge?

Liquid-filled pressure gauges provide a number of advantages:


  • The liquid absorbs vibration and pressure spikes.
  • The dampening action of the liquid enables the operator to take reading during conditions of rapid dynamic loading and vibration.
  • The liquid lubricates all moving elements, dramatically reducing wear in the movement.
  • Because most liquid-filled gauges are filled with non-aqueous liquid and hermetically sealed, they perform in corrosive environments and are immune to moisture penetration and icing.

What if my applications encounter severe pressure fluctuation or pulsation?

In applications involving severe pressure fluctuation or pulsation, the use of restrictors and/or snubbers is recommended. In addition, liquid-filled gauges increase the service life of gauges in these conditions. WIKA liquid-filled gauges are generally filled with glycerine. Silicone (for greater temperature extremes) and Halocarbon (for use with oxidizing agents such as chlorine, oxygen, and hydrogen peroxide) are also available.


What if my connections are atypical?

Radial (LM) and back (CBM or LBM) connections are available for most WIKA gauges. WIKA stocks gauges with standard NPT threaded connections. Other types such as metric threads, straight threads, hose barbs, and special fittings are available as a special order. Pressure gauges should be mounted in the upright position. For applications where the gauge is mounted sideways, horizontal, or upside down, contact WIKA Customer Service for gauge type compatibility.


What is normal ambient pressure for WIKA gauges?

Please refer to the table below.


Fill Fluid
Allowable Operating Range
99.7% USP, Organic
1118 Centistokes at 68°F
-4° to 140°
-20°C to 60°C
DOW Corning 200 fluid
1000 Centistokes at 77°F
-40°F to 140°F
-40°C to 60°C
Halocarbon Products
4.2 Centistokes at 68°F
-40°F to 140°F
-40°C to 60°C


What is WIKA accuracy for pressure gauges?

WIKA stocks gauges with accuracies of ± 3/2/3% to ± 0.1% of span (ASME Grade B to Grade 4A). Generally, the more accurate gauges are larger and more costly.


What pressure range should I work in?

A gauge range of twice the working pressure is generally selected. The working pressure in all cases should be limited to 75% of the gauge range. Where alternative pressure and pulsation are encountered, working pressure should be limited to 2/3 of the gauge range.


When is liquid-filled gauge case venting necessary?

For pressure gauges with full-scale ranges of 300 PSI and below (including vacuum and compound ranges of 30° HG-0-200 PSI and below), case venting (after the gauge is installed) is necessary to preserve the accuracy. Temperature fluctuations during shipment and in the process application cause the liquid filling to expand and contract which, in turn, increases or decreased case pressure. As a result, accuracy can be decreased and the pointer may not return to zero properly until the gauge is vented to the atmosphere.


Does WIKA make a gauge with less than +/-0.75% accuracy?

Yes, WIKA sells gauges with accuracies down to +/-0.1% of span. For more information please visit our Mechanical Pressure Section, under the High Precision Test Gauges section.


Does WIKA make Monel cases?

WIKA only makes Monel cases as a special order request. Typically, the industry usually prefers instead of a MONEL case material is a 304 SS case that is either epoxy coated or PTFE coated. This is a much more cost effective solution, but provides the same level of protection.


Can fill fluid be purchased separately?

Yes, we sell Glycerine, Silicone Oil, Halocarbon and Fluorolube in 8oz. squirt bottles or in gallon size. These are sold separately. 


Is it possible to get a 7500 psi range with the Type 232.25 pressure gauge? With a 7500 psi range, what would the resolution be and what increments would be labeled on the gauge?

We can produce the model 232.25 4.5" or 6" in the 7500 PSI pressure range. The accuracy of the gauge would be +/- 0.5% according to ASME B40.100. The standard figure intervals would be every 750 PSI, but we could do every 500 PSI if needed.


The glass on my WIKA gauge has cracked. Can it be repaired? If so, what do I need to do?

Yes the glass can be repaired, please visit Support – Product Return (RMA)  and follow the steps provided or call 1-800-645-0606; select options 1 and then 4. (Hours for phone support are Monday-Friday, 8:00 am – 5:00 pm (EST). If calling after regular business hours or during a holiday, please leave a voicemail message.)


You may also send an e-mail to or fax to770-338-5109.


I'm looking for a pressure gauge, but all I know is the diameter, scale and mount. How can I find the gauge I need?

  • You can go to Products – Pressure Gauges – choose a pressure gauge category – then select a gauge based on your needs.
  • If the gauge is from a competitor please visit our Support section and the Product Cross Reference – Either click on the product category or enter the information and an equivalent WIKA product will appear.
  • If you still cannot find what you are looking for go to Support – Technical Support – Pressure Gauges and contact the person(s) listed. Or visit our online customer center (OCC) – click on the link – enter your log in or sign up – access your account and view your orders to see if there is a match available.

    What is a "Newton type" or force pressure gauge and does WIKA carry them?

    A force gauge is a measuring instrument used all across industries to measure the force during a push or pull test. Applications exist in research and development, laboratory, quality, production and field environment. There are two kinds of force gauges today: mechanical and digital force gauges. WIKA can produce both the force gauge in Newton’s and pressure gauge in N/m2.


    What is a moisture /density gauge and does WIKA have them?

    A nuclear density gauge is a tool used for civil construction, in the petroleum industry, mining and archeology purposes. It consists of a radiation source that emits a directed beam of particles and a sensor that counts the received particles that are either reflected by the test material or pass through it. By calculating the percentage of particles that return to the sensor, the gauge can be calibrated to measure the density and inner structure of the test material. WIKA does not manufacture moisture/density gauges.


    Pressure Transmitters and Transducers


    Can I get product prices and delivery estimates online for pressure transmitters and transducers?

    This information is not currently available online. Please contact Electronic Pressure Measurement Customer Service for this information.


    How do Intrinsically Safe and Explosion-Proof pressure transmitters differ?

    Intrinsically safe pressure transmitters, by their design, limit the thermal and electrical energy to a point where ignition is not possible. In contrast, explosion-proof pressure transmitters work on the principle of containment, where the pressure transmitter is enclosed in a housing that is designed to contain, control, cool and then vent any possible explosion. This is accomplished by specially designed flanges, or more commonly, with threaded joints. The hot gases must travel a specific distance along the threads before they are cool enough to be safe. Care must be taken to avoid cross-threading the joints during assembly. In addition, heavy conduit and seal-offs are required to maintain an explosion-proof system.


    What is the difference between a pressure transmitter and a pressure transducer?

    A pressure transducer is a device that converts energy from one form to another.  It takes a physical property such as pressure or temperature and converts it into an electrical signal, such as 2mV per volt, 0-5V or 0-10V.


    A pressure transmitter amplifies an electrical signal and converts it to a 4-20mA output.  Because a 4-20mA signal is minimally affected by electrical noise and resistance in the signal wires, a 4-20 mA output signal is best where the signal must be transmitted long distances.  It is therefore common to use a pressure transmitter for applications where the signal wire runs for distances up to 10,000 feet.


    What is the electronic pressure measurement return policy?

    Special order items are not returnable. To return standard items, you may request an RMA by contacting WIKA's RMA Group in one of three ways:


  • Phone: 1-800-645-0606; select options 1 and then 4. (Hours for phone support are Monday-Friday, 8:00a-4:30p EST. If calling after regular business hours or during a holiday, please leave a voicemail message.) 
  • Fax: 770-338-5109 
  • Email:

    How can I get a quote for a pressure transmitter? How long does it take to get my quote?

    Please visit the Request for Quote page - Click on Transmitters, Electronic Meters & Displays – from there, fill out the required fields and submit.  A quote typically takes 24-48 hours business hours.


    Can the DI-15 cover be made in green as opposed to red?

    Both the cover and the internal LED’s of the DI-15 are red. It is technically possible to build the units with green display and cover as a special order but there would be a minimum quantity required.


    Diaphragm Seals


    When should a diaphragm seal be used with a pressure gauge?

    Because the sensing element of a pressure gauge may be exposed directly to the measured medium, consider the characteristics of this medium. It may be corrosive, it may solidify at various temperatures, or it may contain solids that will leave deposits inside the sensing element. For pressure fluids that will not solidify under normal conditions or leave deposits, a Bourdon tube gauge is acceptable. Otherwise a SealGauge or diaphragm seal should be applied.

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