ITT Controls

3010 - 2013

Barton Instruments Models 288C / 289A / 290D / 291B

These Barton Instruments DP Indicating Switches are responsive to relatively low magnitudes of pressure differences at high static pressures. They are offered in a wide range of DP ratings and can withstand over-ranges equal to their rated SWP. Typically they are used to energize alarm or control circuits.

• Stable calibration and negligible SP shift
• Minimal Maintenance
• Available in stainless steel (M289AS)


M199-based 289A and 291B are used where maximum sensitivity is required in lower DP ranges, where a field change is anticipated, or when a built-in pulsation dampener is needed
to control the unit's response time. The 289C is also available in stainless Steel (289AS).
M224C-based 288C and 290D are used in applications that require extended DP ranges (beyond M199-based units) or whenever size and weight are prime considerations.
The 288C is also available in stainless steel (288CS).

The indicating pointer travels through
a 270° arc over a six-inch (150mm)
dial. Scales are calibrated in uniform
increments for measurement of DP or
liquid level; square root available for
direct reading of flow rate; also
special scales for tank fluid quantity.
Weather-Proof Case
The weather-proof case is made of
die-cast aluminum, finished with
weather-resistant black epoxy resin
paint. The polycarbonate lens is
secured in the bezel with elastomer
ring, reducing possibility of breakage
and acts as a seal between bezel and
case for a moisture-, fume-, and dustfree
atmosphere for the indicating

Explosion-Proof Case
NEMA 4 case has a large cover for
maximum readability; switches/adj
accessible with cover removed. Case
is certified for Class I, Div. 1, Group B
Explosion-proof service.

Indicating Mechanism
A precision made, jeweled, rotary
movement employs a thermally stable
Ni-Span-C hair spring. Zero/range adj.
via micrometer screws. Zero adj.
accessible without removing
scaleplate or pointer. The rotary
movement/pointer are fully protected
from over-range in either direction.

All models are available in single or
dual snap-acting mechanical contact
(SPDT) switch configurations. They
can be set for high or low, or both
when two contacts are furnished. The
switches are adjustable from 5% to
95% of full scale range. Switch set
points are adjusted with a control
screw located flush with the scale;
contact setting indicated by a small
scale on scaleplate. Switch contacts
can be set to either open or close
with increasing or decreasing DP
(reverse action by reversing lead wires
at terminal block).
• AC Rating:
• 5 amps 125V
• 2.5 amps 126V-250V
• DC Rating:
• (Inductive) 1.0 amps 30V
• (Resistive) 3.0 amps 30V
Switch connections are 1/2" NPT
Female or an optional flexible conduit
(up to 8 feet in length).