IRROMETER – Replaceable Tip Model SR

SKU: 206

Tensiometer Service Unit

Attention all Irrometer Tensiometer customers

Please note that the Tensiometer Service Unit, catalog number 1001, is necessary for all Irromter Tensiometer installations. This item is not used with the Warermark series, and is only needed for fist time Tensiometer customers. The kit includes the reservoir solution and a pump to remove air from the chamber of the tensiometer, without, the reading this device will not be accurate.

The IRROMETER Model "SR" is available in standard lengths of 6, 12, 18, 24, 36 inches (15, 30, 45, 60, 90 cm). For longer lengths add $10.00 per foot (30cm).

WARRANTY: One year 


Instrument body materials: Butyrate body, ceramic tip, neoprene stopper
Reservoir section dimensions: Height 4.75in.(120mm) - 5.125in.(130mm) including cap
Diameter 2 in. (51 mm) - 2.15 in. (55 mm) including cap
Body tube section dimensions: Length: Ranges from 6 in. to 60 in. (15 cm to 150 cm) - special lengths available
Diameter: 875 in. (22 mm)
Instrument weight: 12 in. (30 cm) is .968 lb. (0.439 kg) with increases of .252 lb. (0.114 kg) per foot
Ceramic tip: Replaceable threaded tip with O-ring seal. White tip – used for most soil types

 1008 Standard Vacuum Gauge

Dial size 2 in. (51 mm)
Case Hermetically Sealed Thermo Plastic Rubber
Window Inner - Polycarbonate, Outer - Butyrate
Dial Scale of 0-100 cb (kPa), white with contrasting green markings
Accuracy +- 3-2-3% of span ASME B40.1 Grade B
Mechanism Bronze Bourdon Tube
Connection Standard 1/4 in. NPT - Brass Bottom Mount
Operating temperature -40° to 150° F (-40° to 65° C), 32° to 150° F (0° to 65° C) for water service


The IRROMETER operates on the tensiometer principle, which measures soil water tension. Soil water tension is the energy (vacuum) applied to soil by the plant as it draws in water for nutrition. This force is measured in centibars (cb) or kilopascals (kPa) of tension with a high reading indicating the dry end of the scale and a low reading indicating the wet end of the scale. The IRROMETER instrument consists of a sealed, fluid filled tube that is equipped with a porous ceramic tip and a special vacuum gauge. They are installed in the ground with the tips placed at desired root zone depths. As the soil dries (increasing tension), fluid is drawn out of the instrument. This reduces the fluid volume in the IRROMETER, thus creating a partial vacuum which is registered on the gauge. The drier the soil, the higher the gauge reading. An irrigation application or rainfall event reverses this action. As water flows back into the soil (and the IRROMETER), tension is relieved in the soil and the instrument, resulting in a lower gauge reading (lower tension). In effect, the instrument is indicating how hard the roots are working. Due to the IRROMETER’s unique principle of operation, no calibrations are necessary under normal operating conditions for different soil types. A gauge reading of 50 cb (kPa) indicates that the roots are extracting the same amount of moisture whether the crop is planted in sandy soil or clay soil.


IRROMETERS can be used for manual measurement and tracking of soil moisture status for most soil types. When equipped with optional electronic output and data logging equipment, measurement and tracking can be done automatically. The standard vacuum gauge on this model can be replaced with electronic measurement options, or automatic switching devices which can activate peripheral equipment at desired soil water tension levels. See the “Automation and Output Options” specifications for more details. The Model SR uses a replaceable tip for easy servicing in the field. It is designed for general use with row, tree and field crops.


The irrigation system shall incorporate soil moisture indicators to aid in making irrigation scheduling decisions. The soil moisture indicator shall operate on the tensiometer principle and indicate soil water tension, displaying in units of

centibars (cb) or kilopascals (kPa). It shall have a hermetically sealed gauge that remains full of fluid even if the instrument tube is completely drained. Tube shall be constructed of durable plastic that is impervious to attack by soil chemicals, with a replaceable ceramic sensing tip. It shall include a fluid reservoir with a submerged valve, whereby fluid can be drained into the tube by turning the cap. All ceramic to plastic connections shall be guaranteed leak proof. The soil moisture indicator shall be an IRROMETER Model SR as manufactured by the IRROMETER Company, Inc. of Riverside, California.

Hermetically Sealed Gauge — Accuracy and long lifeareensuredbyahermeticallysealedcoverwitha molded-in diaphragm which keeps dirt and moisture out and compensates for variations in temperature and barometric pressure.

Air-Free Gauge — The water seal prevents air from entering gauge, as gauge and chamber remain full regardless of fluid level in instrument.

The IRROMETER Body — is constructed of tough durable plastic impervious to attack by soil chemicals or electrolysis.

The IRROMETER — is available in standard lengths of 6, 12, 18, 24, 36, 48 & 60 inches (15, 30, 45, 60, 90, 120, 150 cm).

Closure — Large cap for easy operation and better control. Cap removes for filling reservoir. Submerged valve gives a positive leak proof seal. Servicing is instantaneous – a twist of the wrist.

Reservoir — holds a reserve supply of fluid sufficient for several irrigation cycles under average operating conditions. Unscrewing cap part way releases air and fills tube to replace fluid lost by the action of drying soil.

Ceramic to Plastic — connections are permanently leak proof.

Ceramic Tip — Replaceable tip is easy to service in the field and has many times the strength of conventional tips. It is more porous to give quick response to variations in soil moisture.


There are no materials for downloading