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YSI WaterLOG Bubbler / Pressure Sensor (H-3553T)

The Bubbler has an improved controller and pressure regulator that use a sophisticated system of sensors and valves to regulate the bubble rate and purge pressure. And to keep the sediment from settling around the orifice line, this Bubbler provides a purge feature to keep the pressure at a desired level. You can even start a manual purge, anytime, with the touch of a button. This system was made for those who don't have time to mess around at the site.

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Designed to replace nitrogen gas purge bubbler systems, the WaterLOG® Bubbler (H-3553T) provides the highest purgre pressure in the industry (up to 90 PSI), while maintaining high accuracy thanks to its built-in NIST traceable pressure sensor. With programmable flow rates, a sleep current of 6mA, and an RS-485 connection, it is sure to be a favorite among your products.

  • Stand alone RS-232 menu setup
  • Continuous display readout
  • Built-in calibrated pressure sensor (no external pressure sensor needed)
  • 'Purge', 'Read' and 'Tank Release' buttons
  • RS-485 MODBUS Client/Slave device
  • Auto update mode, measures itself based on user defined rate
  • Adjustment knobs to manually set the stage and sensor SDI-12 address
  • SDI-12 interface, 4-20mA output and RS-232 data output

Pressure Less than or equal to 0.02% of full scale output (FSO) over temperature range
Pressure Hysteresis Less than 0.01% of FSO
Linearity Less than 0.02% deviation
Temperature Internal temperature ±1° C over tem­perature range
Long-term Stability Drift is less than ±0.05% of FSO per year

Standard Pressure Ranges are 15 PSI and 30 PSI

Custom calibration ranges available

Resolution Pressure

1 part in 1,000,000 (0.0001%)


1 part in 1,000,000 (0.0001%)

Bubbler Gas Delivery

Microprocessor controlled unit

Gas Flow Technology Constant mass Technology
Gas Flow Control Bubble rate is user programmable from 30 to 120 bubbles per minute based on 1/4 in. (6.35 mm) tubing. Auto zero error controlled flow nozzle
Purge Functions Purge Pressure Level User Selectable 30 PSI to 90 PSI


SDI driven purge

Purge sustain option (10-30S)

Automatic / programable

Compressor Type

Piston Compressor


Low duty cycle (7 hours typical runtime per year at 60 bubbles per minute into 12 ft. (3.65 m))

Purges not included

General Pressure Overload

Less than 2 times the rated pressure

Media Capability

Non-corrosive dry gases only


NEMA 4 enclosure

Range Pressure Depth Accuracy
0 to 15 PSI 0 to 34.6 ft. (10.54 m) ±0.007 ft. (2.1 mm)
0 to 30 PSI 0 to 69.20 ft (21 m) ±0.014 ft. (4.26 mm)
0 to 50 PSI 0 to 115.35 ft (35.16 m) ±0.023 ft (7.03 mm)
Size Housing

10.5 in. L x 9 in. W x 6.3 in. H

266.7 mm L x 228.6 mm W x 160 mm H

Weight Housing 9.5 lbs (4.3 kg)
Material Housing


Atmospheric Vent Sintered bronze, #10-32
Power Requirements Voltage Output 10.0 to 16.5 V DC

Standby: 6mA
Compressor Active, No Pressure: 3 A

Compressor Active, Full Pressure: 6 A
Startup Surge Required: 15 A

Based on a 60 bubbles/min flow rate with a 15 min measurementcycle and a 1 purge/day frequency. Average active current 20mA


7-pin Circular Military Connector Power, SDI-12, 4-20mA and RS-485
3-pin Circular Military Connector RS-232 Data and Menu Setup Port

Main Connector Cable with 6 ft. (1.8288 m) pigtail provided.

RS-232 Connector cable optional.


Sealed Bendix type circular

Pressure Inlet

1/8 in. (3.81 cm) female NPT

SDI-12 Baud Rate 1200
Protocol SDI-12 V1.3, 7-bit even parity, 1 stop bit
Output Voltage Level Minimum high level: 3.5 volts
Maximum low level: 0.8 volts
Response Time 8- second measurement sequence (programmable)
RS-485 Interface Protocol

RS-232, 8bit, No Parity, 1 stop bit

Baud Rate 9600
4-20mA Output Type 4-20mA, optically isolated .75 ft (2.67 m)
Loop Voltage 8.0V min 35V max
Resolution 16 bit resolution ±-0.24uA (16-bit DAC)
Accuracy ±10uA
General Specifications
Operating Temperature -40 ° to +60 ° C
Compensated Range -40 ° to +60 ° C
Storage Temperature -40 ° to +80 ° C
Warranty The WaterLOG® H-3553 Bubbler is warranted against defects in materials and workmanship for twenty-four months from date of shipment.

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