User guide

DIFFERENTIAL PRESSURE GAUGE/SWITCH
For efficient working of your gauge, please read all instructions
carefully before attempting to install.
Caution: Do not exceed maximum operating pressure given
on the gauge label. Check fluid compatibility with wetted parts
before use. Do not mount the gauge at locations where the
gauge is subjected to vibrations.
Operating principle: High and Low pressures are separated
by a sensor assembly consisting of a magnet, diaphragm and
a range spring. The difference in pressure causes the sensor
assembly to move in proportion to the change against a range
spring. A rotary magnet, located in a separate body compart-
ment and isolated from the acting pressures is rotated by mag-
netic coupling as per the linear movement of the sensor
assembly. A pointer attached to the rotary magnet indicates dif-
ferential pressure on the dial. (see diagram)
Note: These instruments are calibrated to give ±3% full scale
accuracy on ascending readings.
Installation: For better performance the gauge should be
mounted horizontally with the dial vertical. Depressurize the
system and connect the high and low pressure lines of your
system to the “High” (+) and “Low” (–) ports of the gauge, re-
spectively.
High pressure: Connect tubing from source of high pressure
to either of the two high pressure ports. Plug the port which is
not used.
Low pressure: Connect tubing from source of low pressure
to either of the two low pressure ports. Plug the port which is
not used.
The instrument is now ready for operation. Apply “High” and
“Low” pressures simultaneously, to avoid damage to the inter-
nal parts.
The model 1134 consists of a convoluted diaphragm to sense
the pressure difference. It can withstand maximum operating
pressure up to 35 psi/2.4 bar and temperature up to 140°C/60°F
maximum for all ranges.
If pressure exceeds the rated maximum pressure, “O” rings
and diaphragm inside the pressure chamber, will be damaged.
If maximum operating pressure is within the allowable limit of
35 psi/2.4 bar, but the differential pressure exceeds instrument
range, there will be no damage to the instrument. The pointer
will only go the extreme right end of the scale.
The pointer will always be in the zero box with no pressure ap-
plied. Calibration or adjustment of pointer is not recommended
unless the pointer is outside the zero box.
For zero calibration adjustments, turn the pre-compression
screw (located in the high (+) sideport) clockwise or counter
clockwise. Do not attempt to open/repair the gauge. This screw
is located in the high side connection.
Precautions: Do not connect “High” and “Low” ports to wrong
pipe ends. Do not subject the instrument to excessive vibration.
Field repairs are not recommended, because if not reassem-
bled properly calibration will be affected.
Standard accessories: Two 1/8 NPT (M) adapters for tube
connection to inline or back ports. Two 1/8 NPT (M) plugs to
plug the ports not in use. Three screws, each of M3 x 4 and
M3 x 20 for flush mounting along with three flush mounting
clamps. See reverse for more information.
For surface mounting (option): For surface mounting, a sur-
face mounting plate with two spacers is supplied. See reverse
for more information.
Troubleshooting: If the gauge does not show reading or
shows incorrect reading.
• See that the unused ports are properly plugged.
• Pressure tubing is connected without leaks, blocks or
twists.
• Installation done as per the recommended procedure.
• Foreign/magnetic particle have entered the sensing chamber.
• If problem is not resolved by referring to the information
above, contact your supplier of Ashcroft
®
gauges.
Installation Instructions for
ASHCROFT
®
Model 1134
Differential Pressure Gauge/Switch
ROTARY
MAGNET
MAGNET
POINTER
HIGH
CONVOLUTED
DIAPHRAGM
LOW
RANGE
SPRING
10
0
2
0
5
0
REED SWITCH
30
4
0
© Ashcroft Inc., 250 East Main Street, Stratford, CT 06614-5145, USA, Tel: [phone], Fax: [phone], www.ashcroft.com
All sales subject to standard terms and conditions of sale.
I&M008-10122-6/07 07/13
Model 1134 Convoluted Diaphragm