Belimo 22PDP-588A : Water Diff Pressure with LCD, 4 Ranges (0-250 psi), V/mA Universal, 17-4 PH SS, 10-ft Armored Cable, NEMA 4X, cULus, 24V, 5-Yr Warranty

What does the 22PDP-588A measure and output?

It measures the differential pressure between two points in a water or water-glycol hydronic system — the pressure at the + port minus the pressure at the − port. The default range is 0–250 psi (Range1), with 4 DIP-selectable sub-ranges narrowing to 0–25 psi at the most sensitive setting. Output is universal: a single on-board DIP switch selects between 0-5V, 0-10V, or 4-20 mA, so one SKU works with any BAS controller.

Why are there 4 measuring sub-ranges?

The 4 sub-ranges let one SKU cover applications with very different operating points — and choosing a narrower range improves BOTH analog resolution AND accuracy. Range1 (factory default) covers the full envelope at ±1.0% FS accuracy. Range2 through Range4 map the same output signal across progressively narrower pressure spans — ±0.5% FS, ±0.4% FS, ±0.4% FS. For example on the 22PDP-588A: balance work on a low-static fan-coil might use Range2 (0–25 psi) for 10× the resolution and tighter accuracy. Note that FS (full scale) always references the maximum sensor range, so a ±0.4% FS on Range3 is the same absolute pressure error as ±0.4% on Range1, just less significant relative to the smaller working range.

How does the universal output (V or mA) work?

An on-board DIP switch selects the output mode: 0-5V, 0-10V, or 4-20 mA. The default is 0-10V. To change, open the housing and flip the appropriate DIP switch — no separate SKU needed. This is useful for installations where the spec package called for one output type but the BAS turned out to need another (common when controllers are value-engineered to a different brand mid-project). 4-20 mA is preferred for cable runs over ~150 ft or in electrically noisy environments; 0-10V is simpler and uses less power for short runs.

Why is the burst pressure so high — 2000-5000 psi vs nominal 100-250 psi?

Burst pressure on the 22PDP-588A is 5000 psi — 20× the high end of the measuring range. This is intentional: hydronic systems experience transient overpressure events from water hammer (sudden valve closures), pump starts, hydrostatic test events during commissioning (typically 1.5× operating pressure), and pressure-relief valve cycling. The stainless steel 17-4 PH wetted parts and strain-gauge construction comfortably handle these transients without calibration drift or seal damage.

Why armored cable instead of standard PVC?

Armored cable is rated for high-abuse environments — mechanical rooms where the sensor cable might be subject to routine maintenance traffic, vibration, abrasion against pipe lagging, or rodent damage. Some local codes also require armored cable in certain installations. For standard installations where the cable runs in a protected route or conduit, the PVC variant works fine at a lower price point.

What media can this sensor work with?

Designed for water and water-glycol mixtures (any concentration). The stainless steel 17-4 PH wetted parts and NBR seals are qualified for hydronic service. NOT designed for refrigerants, aggressive industrial chemicals, ammonia, or chlorinated brines — these can damage the NBR seal or attack the wetted parts. Fluid temperature range is -40 to 220°F (frost protection required below 36°F on the fluid side).

Where can I install this sensor?

Indoor mechanical rooms, hydronic pump skids, penthouse air-handler rooms — anywhere with a hydronic system needing pump head, balance valve verification, heat exchanger pressure drop, or coil pressure drop monitoring. NEMA 4X / IP65 rated for wet/washdown environments. Operating ambient 32-122°F (0-50°C); fluid temperature -40 to 220°F. The transparent PC top cover keeps the LCD readable without opening the housing — mount where a technician can see the display during commissioning and service.

How is this different from the 22WDP family?

Both measure water/glycol differential pressure, but at very different tiers. 22PDP-588A (this SKU): premium tier — LCD display, universal V/mA output (switch-selectable), 4 selectable sub-ranges, stainless 17-4 PH wetted parts, 5000 psi burst pressure, cULus listed, 10-foot factory cable. 22WDP family: standard tier — no LCD, fixed V OR mA output per SKU, single fixed range per SKU, ceramic diaphragm, 300 psi constant burst, CE-only. Choose 22PDP when you need on-housing readout, universal output flexibility, code-required UL listing, or extreme burst pressure tolerance. Choose 22WDP for budget-conscious hydronic balancing where the BAS handles all the display and the operating point is well-known at spec time.

Does it need 24V power?

Yes — 24 VAC or 24 VDC supported (AC 21.6-26.4V / DC 21.6-26.4V). Power consumption is 3.1 VA AC / 1.4 W DC — higher than the simpler 22WDP family due to the LCD display and universal-output electronics. Compatible with standard 24V control transformers shared with actuators and other sensors.

How is the sensor installed and wired?

Tap two 1/4" NPT connections on the piping you're measuring across — one upstream (high pressure side → + port) and one downstream (low pressure side → − port). Use installer-supplied PTFE thread sealant. Connect the two ports to the sensor with rigid or flexible tubing. The 10-foot factory-installed cable terminates at a pluggable spring-loaded terminal block — wire to your BAS panel directly (max 2.5 mm² conductor). Open the housing once to set DIP switches for output type and sub-range, then close and seal. We recommend isolation valves on both tubing lines for serviceability.