Dwyer A3000 User Manual

Bulletin B-33-A

Ø4-13/16 [122.24]

HOLE REQUIRED FOR

PANEL MOUNTING

1/2 NPT(M) PRESSURE CONNECTION.

SINGLE HIGH PRESSURE CONNECTION

FOR SERIES 36000S MODELS.

SNAP RING GROOVE

2-1/2 [63.50]

2-1/16 [52.39]

2 [50.80]

1-1/4

[31.75]

(4) 6-32 HOLES

EQUALLY SPACED ON

A 5-1/8 [130.18] B.C.

Ø4-47/64

[120.25]

Ø5

[127.00]

Ø4 [101.60]

FAC E

5-1/2 [139.70]

O.D.

MOUNTING

RING

5/8 [15.88]

5/8 [15.88] PANEL

MAX

3/16 [4.76]

3-7/8 [98.43]

5-1/8 [130.18]

6-3/8 [161.93]

(7-5/8 [193.68])

4-3/8 [111.13]

HOUSING REMOVAL

3/4 CONDUIT

CONNECTION

Ø4-3/4

[120.65]

3-7/8 SQ

[98.43]

1/8 FEMALE NPT HIGH

PRESSURE CONNECTION

1/8 FEMALE NPT LOW

PRESSURE CONNECTION

Series A3000 Photohelic®Differential Pressure Switch/Gage

Specifications - Installation and Operating Instructions

Fig. A

NOTE: Detailed dimension drawings are available from our Customer Service

Dept. for PHOTOHELIC

For weatherproof housing, request no. 13-700132-00. /For explosion-proof

The Series A3000 PHOTOHELIC®Switch/Gage is a versatile
2-in-1 instrument combining a time-proven Magnehelic

®

differen­tial pressure gage with low/high pressure switches. It is designed
to measure and control positive, negative or differential pressure of
air or other non-combustible, non-corrosive gases. Gage reading

INSTALLATION

1. Location: Select a clean, dry, vibration-free location where

ambient temperatures will be between 20 and 120°F (-6.67 and

48.9°C). Tubing supplying pressure to the instrument can be prac-

tically any length but long runs will increase response time slightly.
is unaffected by switch operation. Switch set points are easily
adjusted with knobs located on gage face. Applied pressure and
switch set points are fully visible at all times. Deadband is one
pointer width, less than 1% of full scale. Each set point controls a
DPDT relay and both relays can be interlocked to provide variable
deadband control.

2. Position: The PHOTOHELIC

for use with scale in a vertical plane. Operation at other angles may

affect accuracy and/or require zero adjustment. Most models can

be specially calibrated at the factory for other positions if specified

at time of ordering. Ranges below 1˝ W.C. must be used only with

scale vertical.

SPECIFICATIONS
GAGE SPECIFICATIONS
Service: Air and non-combustible, compatible gases.
Wetted Materials: Consult factory.
Accuracy: ±2% of full scale at 70°F (21.1°C). ±3% on -0 and

±4% on -00 models.
Pressure Limits: -20" Hg. to 25 psig (-0.677 to 1.72 bar). MP
option; 35 psig (2.41 bar), HP option; 80 psig (5.52 bar). 36003S
– 36010S; 150 psig (10.34 bar). 36020S and higher;1.2 x full
scale pressure.
Temperature Limits: 20 to 120°F.
(-6.67 to 48.9°C) Low temperature option available.

Process Connections: 1/8˝ female NPT.
Size: 4˝ (101.6 mm) dial face, 5˝ (127 mm) O.D. x 8-1/4˝ (209.55

3. Mounting: The PHOTOHELIC

ed before making electrical connections. The electrical enclosure

is removable at any time regardless of mounting method.

(A) Panel Mounting: Normal mounting is flush or through panel

as shown in Fig. B. Allow 4-

unit for removal of electrical enclosure. Make a 4-13/16˝ (122.24

mm) diameter hole in panel. Insert the PHOTOHELIC

Switch/Gage unit from front of panel and slip mounting ring over

case from behind with stepped side facing rear. Fit the snap ring

into narrow groove at back edge of the bezel. Thread four 6-32 x

1-1/4˝ mounting screws into tapped holes in mounting ring and

seat it against snap ring. Tighten screws against back of panel.

See Fig. B.

mm).

Weight: 4 lb (1.81 kg).
SWITCH SPECIFICATIONS
Switch Type: Each setpoint has 2 Form C relays (DPDT).
Repeatability: ±1% of full scale.
Electrical Rating: 10A @ 28 VDC, 10A @ 120, 240 VAC.
Electrical Connections: Screw terminals. Use 167°F (75°C)

copper conductors only.
Power Requirements: 120 VAC, 50/60 Hz; 240 VAC & 24 VAC
Power optional.
Mounting Orientation: Diaphragm in vertical position. Consult
factory for other position orientations.

Set Point Adjustment: Adjustable knobs on face.
Agency Approvals: UL: File No. E38121, Vol. 1, Sec. 4; CSA:

File No. LR22541-34; CE: EN 61000-6-2: 1999, EN 6100-3-2:
2000, EN 61000-3-3: 2000.

DWYER INSTRUMENTS, INC.

P.O. BOX 373 • MICHIGAN CITY, INDIANA 46361, U.S.A. Fax: [phone] e-mail: [e-mail]

Phone: [phone] www.dwyer-inst.com

®

switch/gages as installed in two optional enclosures.

housing, request no. 13-700113-01.

®

Switch/Gage is factory calibrated

®

Switch/Gage is normally mount-

3

/8˝ (111.13 mm) clearance behind the

Fig. B

®

(B) Surface Mounting with Remote Relays: Where it is pre-

(3) Ø3/16 [4.76] MOUNTING

HOLES EQUALLY SPACED ON A

401/8 [104.78] B.C.

Ø3/4 [19.05] WIRE

CONNECTION HOLE

1-1/8

[25.58]

1-1/8

[28.58]

Ø3/16

TYP 4 PLACES

4-9/32

[108.74]

4-9/32

[108.74]

5

[127.00] SQ

ferred to mount the amplifier-relay unit separate from the gage
assembly, the gage is mounted as shown in Fig. B (without ampli­fier-relay package) or surface mounted as shown in Fig. C. Use the
dimensions in Fig. D to locate holes.

Fig. C

Fig. E

Fig. D

(C) Remote Relays Mounting: On factory supplied RMR (remote

mounted relay) units, the amplifier-relay package will be furnished
attached to a mounting plate as shown in Fig. E. Use the hole lay­out in Fig. F for this option. A five foot cable assembly is included
for connecting the two components. Longer cable lengths are
available from the factory.

Fig. F

4. Pneumatic Connections & Zeroing: After installation but

before making pressure connections, set the indicating pointer
exactly on the zero mark, using the zero adjust screw located at
the bottom of the front cover. Note that this adjustment can only
be made with the high and low pressure taps both open to atmos­phere.

Connect the high and low pressure taps to positive, negative, or
differential pressure sensing points. Use 1/4˝ diameter metal or
other instrument tubing and 1/8˝ NPT adapters at the PHOTO-

®

HELIC

pressure switch/gage. Adapters for rubber or soft plastic
tubing are furnished with the instrument for use where this type of
connection is preferred.

If the PHOTOHELIC

®

Switch/Gage is not used to sense differential
pressure, one of the pressure taps must be left open to atmos­phere. This will allow the reference pressure to enter. In this case,
installation of a Dwyer Instruments, Inc. No. A-331 Filter Vent Plug
or similar fitting in the reference pressure tap is recommended to
reduce the possibility of dust entering the instrument.

NOTE: If the PHOTOHELIC

®

switch/gage is over pressured, point­er may “jump” from full scale back to zero and remain there until
the excess pressure condition is relieved. Users should be aware
of possible false zero pressure indications under this condition.