Precision instrumentation for next-generation data center cooling
Product · Pressure Measurement

Pressure Transmitters

Silicon piezoresistive gauge and differential pressure transmitters for every pressure measurement point in a liquid-cooled data center.

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Why It Matters in Data Center Liquid Cooling

Pressure telemetry is what lets operators detect the difference between a filter clog, a failed pump, a closed isolation valve, and a genuine flow problem — before thermal alarms cascade. Accurate, stable differential pressure across heat exchangers and manifolds is equally essential for capacity allocation and pump control.

Supmea's SUP-P300 gauge and SUP-DP differential pressure transmitters combine silicon-on-sapphire or piezoresistive sensors with low-drift electronics, delivering the long-term stability that data center operations demand.

Typical Specifications — SUP-P300 Gauge Pressure Transmitter
Measurement range0–10 kPa up to 0–60 MPa (40+ standard ranges)
Accuracy±0.075%, ±0.1%, ±0.2%, ±0.5% of span (selectable)
Long-term stability±0.1% URL per year
Turndown ratioUp to 100:1 (digital) / 10:1 (analog)
Process temperature−40 °C to +120 °C (standard diaphragm)
Ambient temperature−40 °C to +85 °C
Overpressure2× URL standard; 150× for micro-ranges
Wetted material316L SS (standard), Hastelloy C-276, Monel, tantalum
Process connectionG½″, ½″ NPT, M20×1.5, flange, sanitary
Output signal4–20 mA + HART 7; RS-485 Modbus RTU
Supply voltage10.5–42 VDC
Display5-digit LCD, 270° rotatable
EnclosureDie-cast aluminum or 316 SS; IP67
ApprovalsCE, RoHS; ATEX Ex ia IIC T4/T6
Typical Specifications — SUP-DP Differential Pressure Transmitter
Ranges0–0.5 kPa up to 0–20 MPa differential
Accuracy±0.075% of span (standard)
Static pressure limitUp to 32 MPa working pressure
Zero stability±0.05% URL per year (typical)
Wetted material316L SS diaphragm / silicone fill (standard)
Remote seal optionCapillary-connected remote diaphragm seals, 316L / Monel / tantalum
Output4–20 mA HART, RS-485 Modbus, FOUNDATION Fieldbus

Where This Product Fits in the Cooling Loop

Typical deployment points in data center liquid cooling architectures — from facility water through to rack-level manifolds.

Filter Differential Pressure

ΔP transmitters across inline filters and bag housings provide early warning of particulate loading — the signal that should trigger filter rotation well before flow is restricted enough to affect thermal performance.

Pump Discharge Pressure

Gauge transmitters on CDU primary and secondary pump discharges monitor head pressure for pump performance verification, cavitation detection, and VFD control loop feedback.

Manifold & Rack Inlet Pressure

Compact gauge transmitters on per-rack cooling manifolds verify that every rack sees the specified inlet pressure — essential for equitable flow distribution in multi-rack cold plate deployments.

Heat Exchanger Differential Pressure

ΔP across primary-to-secondary heat exchangers tracks fouling (rising ΔP at constant flow) — the single most useful diagnostic for water-side heat exchanger maintenance planning.

Immersion Tank Head Pressure

Low-range gauge transmitters monitor dielectric fluid level via hydrostatic pressure in single-phase immersion tanks, with compensation for fluid density and temperature.

Expansion Tank & Makeup Pressure

Low-pressure gauge transmitters on closed-loop expansion tanks ensure minimum net positive suction head (NPSH) is maintained and alert operators to system leaks causing pressure drift.

Need help selecting the right configuration?

Send us a P&ID or a short description of your cooling loop. Our application engineers respond with a specification recommendation and quote within one business day.

Engineering & Specification FAQ

The questions we hear most often from specifying engineers, system integrators, and facility operators.

Gauge vs. differential — when do I need each?

Use a gauge transmitter when you need to know the actual pressure at one point (pump discharge, rack inlet, manifold header). Use a differential transmitter when you need the difference between two points (across a filter, across a heat exchanger, or for hydrostatic level). For flow measurement using orifice plates, always use a dedicated differential transmitter — never two gauge transmitters subtracted in software, because the error stacks badly at low ΔP.

What accuracy do I need? Is ±0.075% worth the premium over ±0.2%?

For BMS trending, alarm thresholds, and general loop health monitoring, ±0.2% is entirely adequate and significantly less expensive. Reserve ±0.075% for custody-transfer flow measurement (tenant billing in colocation), for very low ΔP applications where you are using 10–20% of the range, and for measurement chains feeding SLA reporting. In practice, long-term stability and zero drift matter more than headline accuracy for most data center applications.

Can I use these transmitters on glycol-water mixtures?

Yes. Standard 316L SS diaphragms are fully compatible with propylene and ethylene glycol mixtures at the concentrations (25–50%) used in data center loops. The silicone fill fluid inside the diaphragm assembly has a wide temperature tolerance and does not interact with the process fluid. For dielectric fluids (immersion cooling), confirm fill fluid compatibility with the fluid manufacturer — in rare cases, tantalum diaphragms with inert fill are specified.

How do I avoid zero drift from temperature changes?

Three practices: (1) select a transmitter with published temperature effect spec below 0.1%/10 °C; (2) use impulse piping that equalizes temperature between the high and low ports on differential transmitters; (3) for outdoor installations, use a sunshade. Our SUP-DP series publishes full thermal error curves so you can calculate expected drift over your ambient range before specifying.

Do you support HART 7 for diagnostic telemetry?

Yes. All SUP-P300 and SUP-DP transmitters ordered with the HART option support HART 7, which adds enhanced diagnostics (sensor drift tracking, loop integrity verification) and long-tag support. This integrates with asset management systems like AMS Device Manager and PRM, and is exposed via HART-to-Modbus gateways for DCIM systems that don't natively speak HART.

What about water hammer and pressure spikes?

Gauge transmitters specified for standard cooling loop pressures (1.6 MPa or 2.5 MPa nominal) typically have 4–6 MPa overpressure ratings. Brief water hammer events are absorbed without damage. For severe conditions (quick-closing valves, long pipe runs), install an inline pulsation dampener or specify a diaphragm seal, and ensure your selected range leaves headroom for the transient.

Can I calibrate in the field?

Yes. HART transmitters support two-point zero/span trim via a handheld communicator or HART modem. For best accuracy, use a calibrated pressure source (deadweight tester or precision pneumatic calibrator) traceable to national standards. We recommend annual calibration verification as part of the broader site instrumentation maintenance schedule.

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Whether you're designing a new liquid-cooled data center or retrofitting existing air-cooled facilities, our engineers can help you select the right instrumentation package.