Senva PW30M-035-A-250 : Remote Wet-to-Wet Differential Pressure Transmitter, Metal NEMA 3R Enclosure, Selectable 0-5V/0-10V/4-20mA Output, 35-ft Armored Cable + PWT250 (250 PSIG) Sensors, LCD, Made in USA

What does the PW30M-035-A-250 measure and output?

It measures the differential pressure between two physically separated tap points - Sensor A (high side) minus Sensor B (low side). The transmitter supports 16 DIP-selectable differential sub-ranges from 0-1 to 0-500 PSID. Output is one active analog signal, switch-selectable: 0-5 VDC, 0-10 VDC, or 4-20 mA. This SKU ships with a matched PWT250 (250 PSIG) sensor pair - usable for differential ranges up to 250 PSID.

What's the advantage of the PW30's remote sensor architecture?

Traditional wet-to-wet DP transmitters require a bypass valve manifold, brass fittings, copper impulse tubing, and the labor to plumb both pressure points back to a single device body. The PW30 eliminates all of that: PWT sensors mount directly on the pipe at each tap point and connect to the wall-mount transmitter via a single cable. The mechanical and electrical trades can install independently - dramatically reducing total installed cost and shortening the critical path on retrofit projects.

When should I choose the PW30M (metal) versus the PW30W (plastic)?

Choose the PW30M (metal NEMA 3R) for indoor mechanical rooms, equipment skids, and protected outdoor enclosures - the powder-coated steel housing also provides additional EMI/RFI shielding near VFDs and motor starters. Choose the PW30W (plastic NEMA 4X) for wash-down areas, humid or corrosive environments, and coastal/chemical-exposure installations where metal would still corrode despite the powder coating.

When do I use bi-directional mode (DIP 9)?

Uni-directional (DIP 9 = ON, factory default) is correct for almost all HVAC applications where Sensor A is always at higher pressure than Sensor B (pump head monitoring, filter loading, chiller delta-P, system pressure drop). Bi-directional (DIP 9 = OFF) is required when flow can reverse - reversible-flow heat recovery loops, dual-pump systems with auto-changeover, or balance work where the operating sense flips between modes. In bi-directional mode, 0 PSID = 50% of output range (12 mA, 5 V, or 2.5 V depending on output type).

How are the 16 sub-ranges selected?

DIP switches 4-7 binary-encode the sub-range: 0000 = 0-1 PSID, 0001 = 0-2 PSID, 0010 = 0-5 PSID, ..., 1111 = 0-500 PSID. Binary reads right to left - RANGE0 is the rightmost bit (DIP 7), RANGE3 is the leftmost (DIP 4). Example: DIP 4=1, 5=0, 6=1, 7=1 = binary '1011' = 0-100 PSID. Power must be OFF when changing DIP switches; new settings take effect only on power-up. DIP 1-3 set the PWT sensor PSIG (must match the installed PWT pair).

What does the Port Swap (DIP 11) feature do?

If Sensor A was accidentally plumbed to the low-pressure side and Sensor B to the high-pressure side, DIP 11 = LEFT (B-A) swaps the inputs in software - no need to re-plumb. This is one of the most useful field features on the PW30 - it catches a common installation error (especially on retrofits where existing taps weren't clearly labeled) and resolves it with a single DIP switch.

How do I zero the device?

Custom zero: ensure both PWT sensors are at equal pressure (typically shut isolation valves and bleed to atmosphere), wait at least 10-15 minutes for warm-up, then hold the ZERO button for 5 seconds until the LCD blinks once. Factory reset: hold the ZERO button for 10 seconds until the LCD blinks twice - this clears the custom zero and restores factory calibration. A remote ZERO terminal accepts an external momentary contact for ground-floor zeroing of elevated installations.

Is this product BABAA / Buy America compliant?

No - bundles including PWT remote sensors are not BABAA compliant because the PWT sensor elements are not US-sourced. Only Senva's transmitter-only configurations (PW30M-C and PW30W-C) qualify under Senva's 2026 BABAA/TAA/ARRA declaration. For federal, ARRA, or government-procurement projects with domestic-content requirements, order the transmitter (PW30M-C or PW30W-C) and PWT sensors separately - the PWT sensors are still acceptable; they just don't count toward the bundle's domestic content.

What media can this sensor handle?

Water and any media compatible with 316 stainless steel (the PWT sensor diaphragm is 316L SS, the body is 304 SS, 1/4" MNPT process fitting). Typical HVAC: water, water-glycol mixtures, refrigerants, light oils. Fluid temperature at the PWT must stay 32-250 deg F (0-125 deg C). Steam applications require a pigtail siphon ahead of the PWT to cool the media below the sensor's max - condensate sitting in the siphon thermally decouples the live steam from the sensor diaphragm.

What's the warranty?

7 years on the PW transmitter electronics and 2 years on all replaceable elements (PWT remote sensors, cable harnesses, valve manifolds). This is one of the longest electronics warranties in the HVAC sensor category - Senva backs the 7-year warranty with US-based manufacturing and domestic technical support. ZOT Supply is an authorized Senva distributor; warranty claims are processed directly with Senva.