Bubbler (H-3551T)

WaterLOG Bubbler (H-3551)

The Bubbler (H-3551T) is reliable, light weight and requires low power operation by 12-volt battery and solar panel. Operating in depths up to 115 ft. (35 m) with 50 PSI, the Bubbler is ideal for stream, lake, well, tide, ocean, reservoir, waste water—let's just say practically every water monitoring site. With programmable flow rates, a sleep current of 6mA, and an RS-485 connection, it is sure to be a favorite among your products. Pair this Bubbler with the H-350XL and you have a complete bubble gage.

  • Features
  • Specifications
  • Software

Designed to replace the dangerous high-pressure gas bottles, oil sight feeds, flow regulators and leaky manifolds found in gas purge pressure measurement systems, the constant flow Bubbler (H-3551T) will ensure a safer site.

  • No sight feed oil in orifice line
  • No needle valve or diaphragm problems
  • SDI-12 and RS-485 interfaces
  • Automatic purge
  • Programmable bubble rate of 30 to 120 per minute
  • Directly driven by all XL dataloggers using RS-485
  • Connects to H-350XL making a complete bubble gage
  • Compatible with other manufacturers' sensors and data loggers
  • Operates in depths up to 115 ft. (35 m) with 50 PSI
  • No mercury
  • Programmable flow rates
Gas Delivery
Microprocessor controlled unit

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
Pressure Level

User selectable 15 PSI to 80 PSI

SDI driven purge
Remote controlled
Compressor Performance
Type Piston compressor


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

(Purges not included)


Mounting Hardware supplied for wall mounting

Pressure Outlet 1/8 in. (.3175 cm) FNPT

Sensor Pressure Outlet 1/8 in. (.3175 cm) FNPT


10 in. W x 12 in. L x 6 in. H

(25.4 cm W x 30.48 cm L x 15.24 cm H)

Weight 12 lbs. (5.4 kg)
Material Sealed corrosion resistant fiberglass
Power Requirements
Qualified for 12-volt battery operation
Two Supply Inputs Electronics supply via the RS-485 cable (10 to 16 volts)

Compressor supply (10 to 16 volts

24 hour average current draw < 20mA based on a 60 bubbles per minute flow rate with 1 daily purge cycle
Max Current 15 Amps (Surge)
RS-485 Electrical
Baud Rate

Baud Rate 9600

Protocol Flexible
Commands Half-duplex, 8-bit, no parity, 1stop bit
Baud Rate


Protocol SDI-12 V1.3, 7-bit even parity, 1 stop bit
Maximum High Level 3.5 volts
Maximum Low Level 0.8 volts
Response Time 8-second measurement sequence (programmable)
General Specifications
Operating Temperature -40 ° to +60 ° C
Storage Temperature -50 ° to +80 ° C
It is recommended to install unit in weather shielded enclosure
Ordering Information

Base Model Number: H-3551

Gas Flow Technology: Order with the  H-350 XL™ pressure measurement system

Warranty The WaterLOG® H-3551 Bubbler is warranted against defects in materials and workmanship for twenty-four months from date of shipment.

Basic Program: Averaging — v —

Basic Program: Bubbler — v —

Options & Accessories


Bubbler SDI-12 Communication Cable, 25 ft. (7.62 m)


Desiccating Air Dryer (600 Cubic Feet)


Orifice kit used to attach orifice line to system


Desiccating Air Dryer (4400 Cubic Feet)


Replacement Desiccant for H-355-DES-1 Air Dryer


Orifice Line (1000 ft. minimum)


Replacement Desiccant for H-355-DES-1 Air Dryer


Replacement Desiccant for H-355-DES-2 Air Dryer


Installation Kit (includes 2 - 1/8" NPT to 1/8" tube fittings, 1 - 1/8" NPT to 3/8" tube fitting, and 6 ft. 1/8" copper tubing)