Dwyer A3000 User Manual
Page 2
(B) Surface Mounting with Remote Relays: Where it is pre-
ferred to mount the amplifier-relay unit separate from the gage
assembly, the gage is mounted as shown in Fig. B (without ampli-
fier-relay package) or surface mounted as shown in Fig. C. Use the
dimensions in Fig. D to locate holes.
(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 lay-
out 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.
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 atmos-
phere.
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 atmos-
phere. 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, point-
er 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.
Fig. C
(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
Fig. F
Fig. E
Fig. D
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