{"id":3011,"date":"2026-10-21T23:22:16","date_gmt":"2026-10-21T15:22:16","guid":{"rendered":"https:\/\/borrapumps.com\/blog\/pump-suction-discharge-pressure-gauge-location\/"},"modified":"2026-10-21T23:22:16","modified_gmt":"2026-10-21T15:22:16","slug":"pump-suction-discharge-pressure-gauge-location","status":"publish","type":"post","link":"https:\/\/borrapumps.com\/de\/blog\/pump-suction-discharge-pressure-gauge-location\/","title":{"rendered":"Pumpen-Saug- und Entlastungsdruckmessger\u00e4t: Ort: Messen Sie die richtige Menge an Druck"},"content":{"rendered":"

Pump suction and discharge pressure gauge locations should be chosen according to the quantity being measured. For pump differential head, identify suitable measurement points associated with the pump inlet and outlet and account for the actual measurement references. For pressure available to a building or process, a downstream network point may answer a different question. Record whether a discharge reading is before or after a check valve, strainer, control valve, or other restriction. Two gauges displaying pressure do not automatically provide comparable measurements of the pump’s performance.<\/p>\n

State the measurement question first<\/h2>\n

A commissioning engineer may want the head developed by the pump, while an operator wants the pressure reaching a remote outlet. A service technician may be investigating an inlet restriction or a failed check valve. These questions require different evidence. Start by writing the quantity, operating condition, and purpose of the reading before deciding where to install an instrument.<\/p>\n

Label the points on the actual piping drawing. Identify the pump nozzles, valves, strainers, branches, elevations, and any intervening equipment. A label such as \u201cdischarge pressure\u201d is incomplete when nobody knows which side of a valve the connection occupies. Keep the instrument tag and its reference location with the record so later technicians do not compare unrelated readings.<\/p>\n

The pump duty-point calculation guide<\/a> establishes the wider system requirement. A local gauge can contribute to that calculation, but the measurement location determines what the value represents. Do not substitute a convenient gauge for the required reference without accounting for the difference.<\/p>\n

Distinguish pump differential pressure from network pressure<\/h2>\n

A pump adds energy between its inlet and outlet. A pressure reading at the discharge alone does not generally establish that addition because inlet pressure may already be positive or below atmospheric pressure. Measure or otherwise establish the inlet condition using a suitable method, and use consistent pressure references and units when comparing the two sides.<\/p>\n

An instrument farther downstream can include the effect of losses through a check valve, filter, flexible connector, or length of pipe. Its reading can be useful for evaluating the pressure delivered beyond those components, but it is not automatically the same as a reading at the pump outlet. State what is included between the measurement point and the pump.<\/p>\n

The same distinction matters upstream. A suction gauge located before a strainer does not directly reveal the pressure after that strainer at the pump inlet. For a restriction investigation, measurements on both sides of the component may be needed. Define the diagnostic boundary instead of expecting one gauge to answer every question.<\/p>\n

\"ISG
ISG Vertical Inline Booster Pump, Red Original. Illustration based on the original BORRAPUMP product. The setting does not document an actual test, installation or model-specific measured result.<\/figcaption><\/figure>\n

Account for gauge pressure, absolute pressure, and vacuum<\/h2>\n

Gauge pressure is referenced to local atmospheric pressure, while absolute pressure is referenced to a vacuum. A vacuum indication can be expressed in different units and sign conventions. Identify what the instrument actually displays before entering the result in a worksheet. A positive vacuum magnitude should not be casually inserted as a positive inlet gauge pressure.<\/p>\n

For an NPSH assessment, the pressure basis and liquid temperature are particularly important. The NPSH available versus required guide<\/a> explains the additional source and liquid information needed. A pressure reading alone does not establish the vapour-pressure relationship or the margin required for an acceptable suction condition.<\/p>\n

Record the local conditions and the calculation method where a conversion is necessary. Avoid silently combining a gauge-pressure reading on one side with an absolute-pressure reading on the other. The arithmetic can look reasonable while the reference mismatch produces an incorrect interpretation.<\/p>\n

Include elevation and velocity terms where applicable<\/h2>\n

Pressure head is only one part of the energy comparison between two flowing measurement sections. Elevation differences and differences in velocity head can matter. For a defined liquid, the head contribution from a pressure difference is \u0394p divided by density and gravitational acceleration. The complete head comparison must use the appropriate section elevations and velocity terms for the chosen method.<\/p>\n

For an illustrative water calculation, a pressure difference of 100 kPa at an assumed density of 1,000 kg\/m\u00b3 corresponds to approximately 10.2 m of pressure head. That result describes the pressure term only. It is not automatically the final pump head if the measurement sections have different elevations, diameters, or intervening losses. The numbers are an arithmetic example, not a BORRAPUMP performance claim.<\/p>\n

The US Department of Energy’s pump-system sourcebook<\/a> provides the system-assessment background for pressure and performance measurements. Follow the agreed test method and manufacturer’s instructions rather than choosing whichever terms make a measured result resemble the expected curve.<\/p>\n

Decide which side of a check valve answers the question<\/h2>\n

A point between the pump and its discharge check valve can provide information about the pump-side condition. A point after that valve describes the downstream side and may remain pressurised by another source when the pump is stopped. These readings can therefore differ in both running and stopped conditions. Neither location is universally correct for every purpose.<\/p>\n

If a common header is supplied by parallel pumps, header pressure does not identify each branch’s pump condition by itself. Check-valve status, branch losses, operating combinations, and measurement locations affect interpretation. The duty\/standby configuration guide<\/a> helps explain why operating state belongs beside every reading.<\/p>\n

Do not remove or bypass a check valve simply to make two instruments agree. Investigate the layout, flow condition, instrument performance, and intended measurement boundary. Any change to the hydraulic arrangement needs the appropriate review because it can affect isolation, reverse flow, surge, and other operating cases.<\/p>\n

\"ISW
ISW Horizontal Inline Pump, Blue Original. Illustration based on the original BORRAPUMP product. The setting does not document an actual test, installation or model-specific measured result.<\/figcaption><\/figure>\n

Choose instruments and connections for the service<\/h2>\n

Select a pressure range, resolution, materials, temperature suitability, and pressure rating appropriate to the measurement and liquid. Consider whether the fluid contains solids or deposits that can obstruct a small pressure connection. Instrument connections, isolating arrangements, and protective accessories should be chosen by the responsible designer and equipment supplier for the actual application.<\/p>\n

A pressure gauge that survives the system’s maximum pressure may still provide poor resolution at a small operating pressure. Conversely, a sensitive instrument may be unsuitable for expected pressure events. Obtain the relevant measurement and rating information instead of selecting from dial size or appearance alone. Keep the calibration identification with the instrument tag.<\/p>\n

A product such as the ISW horizontal inline pump<\/a> offers a route for requesting the supplied assembly’s approved measurement provisions. Do not drill a casing or modify a nozzle based on a generic article. The manufacturer must confirm permitted connections and the applicable installation requirements.<\/p>\n

Use a location and interpretation table<\/h2>\n
\n\n\n\n\n\n\n\n\n\n
Measurement purpose<\/th>\nLocation information to record<\/th>\nWhat the reading does not prove alone<\/th>\n<\/tr>\n<\/thead>\n
Pump differential head<\/td>\nInlet and outlet sections, elevations, diameters and intervening equipment<\/td>\nThe complete duty without flow, speed and a defined method<\/td>\n<\/tr>\n
Downstream supply pressure<\/td>\nPosition relative to check valves, controls and the receiving network<\/td>\nPressure at the pump discharge nozzle<\/td>\n<\/tr>\n
Suction restriction diagnosis<\/td>\nPositions before and after the suspected restriction<\/td>\nThe cause of every low-flow symptom<\/td>\n<\/tr>\n
Stopped-system investigation<\/td>\nPump state, other sources, valve state and measurement side<\/td>\nThe running pump’s developed head<\/td>\n<\/tr>\n
NPSH assessment<\/td>\nPressure reference, inlet conditions, temperature and source information<\/td>\nAn acceptable suction margin without the full calculation<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

Use the table to write a measurement plan before collecting readings. It does not specify universal tapping distances or acceptance tolerances. Those requirements depend on the equipment, the agreed test method, and the applicable documentation. The Hydraulic Institute’s standards resources<\/a> are a starting point for identifying relevant pump-test requirements.<\/p>\n

Make installation and inspection safe<\/h2>\n

Pressure connections can retain liquid and energy after a motor is stopped. Confirm the safe isolation and depressurisation arrangements before opening or servicing any connection. Account for other pumps, upstream sources, elevated tanks, and stored pressure. Selecting \u201coff\u201d at a controller is not proof that an instrument connection can be opened safely.<\/p>\n

Electrical access and work near rotating equipment require their own controls. The Health and Safety Executive describes electrical isolation for maintenance<\/a>. Apply the site’s approved procedure and the equipment instructions to the actual work. This guide does not authorise opening a pressurised connection or approaching exposed rotating parts.<\/p>\n

Arrange instruments so they can be read and maintained without unsafe access. A technically informative location is not a complete installation design if the gauge cannot be reached or serviced safely. Include access, identification, support, and environmental protection in the design review rather than leaving them until commissioning.<\/p>\n

Record comparable readings and investigate discrepancies<\/h2>\n

Take inlet and outlet readings under the same stable operating condition wherever the method requires a simultaneous comparison. Record flow, speed, valve positions, source levels, and other running pumps. Separate observations collected during different operating states instead of subtracting them as though they represented one duty point.<\/p>\n

If a result appears inconsistent, check instrument zero, units, range, reference, blocked connections, and the actual piping location before diagnosing a failed pump. Compare the reconstructed duty with the centrifugal pump curve<\/a>. A curve comparison becomes meaningful only when its configuration and the measured conditions are known.<\/p>\n

Further learning<\/h2>\n

NPTEL’s \u201cMod-01 Lec-15 Characteristics of a Centrifugal Pump\u201d explains the head-flow performance background used to interpret a measured duty. The lecture supports the hydraulic context; the actual tapping arrangement and test method still require the equipment and project documents.<\/p>\n