Ametek 851 Series Operation manual

MODEL 851 SERIES
ELECTRONIC PRESSURE
TRANSMITTERS
FOR HAZARDOUS LOCATIONS
INSTRUCTIONS FOR INSTALLATION,
OPERATION, AND CALIBRATION
F l us hm ount m ode l
s how nm ount e di n
w e l dc oupl i ngonpi pe
851
flushount
851T with
conduit adaptor
for Explosion
Proof rating
K796341 REV D 10/2015
851T std with nut
for  rating

CONDUIT DRAIN
(TO PREVENT MOISTURE
BUILD-UP IN FIELD
TERMINAL COMPARTMENT)
FIELD WIRING
ADAPTOR
COUPLING
D
W
NOMINAL
PIPE SIZE
2
212
3
312
4
5
6
8
10
12
14
16
18
20
24
30
MAX WALL
"W"
.154
.276
.300
.318
.437
.500
.562
.718
.718
.750
.750
.750
.750
.750
.750
.750
PIPE
SCHEDULE
40
80
80
80
120
120
120
120
100
----------
80
----------
80
----------
----------
----------
WELDED TO PIPE
2 1/2" SCHEDULE 40 ILLUSTRATED
PLUG
PLUG IS INSTALLED IN COUPLING:
a) WITHOUT A GASKET TO PREVENT DISTORTION
WHILE WELDING COUPLING
b) WITH A GASKET TO SEAL COUPLING
WHEN TRANSMITTER IS REMOVED
NOTES:
" D " = 1.915 DIAMETER HOLE BY CUSTOMER
" T " = .750 MAX
" W " = SEE TABLE
D
WELDED TO COMMERCIAL PIPE FLANGE
(6" - 150# FLANGE ILLUSTRATED)
T
D
T
WELDED TO TANK WALL
WELDED TO COMMERCIAL 1 1/2"
SOCKETED FITTING
(G & W BONNEY FORGE
3000# 1 1/2" TEE ILLUSTRATED)
T
WELDED TO COMMERCIAL 1 1/2"
WELD FITTING
(G & W BONNEY FORGE 3000#
1 1/2" "SOCKOLET" ILLUSTRATED)
VIEWS SHOWN WITH MODEL 88 FLUSH
BUT SIMILAR FOR THE 851 FLUSH
CAUTION – The Model 851F is shipped with a
Protective cover over the flush diaphragm. Do
not damage the diaphragm after removing the
cover.
To install the Model 851F, the adapter coupling
must be welded to the customer’s pipe @ pipe
flange, or other fitting. Figure 2-3 shows some
suggested installations and lists suggested pipe
sizes, wall and flange thicknesses and hole
sizes. The installation procedure is as follows:
1. Cut hole for adaptor coupling.
2. Thread plug into the coupling (Figure 2-3)
until it bottoms. Do not use the gasket.
3. Position the coupling so that the inside face
is approximately flush with the inside
surface of the customer’s pressure vessel
and tack weld the coupling to hold in place.
4. With the plug still in the coupling, weld a
1/8” fillet all around the coupling. The plug
minimizes the distortion of the coupling
due to the welding operation.
5. Remove the plug.
6. Install the gasket into the coupling (Figure
2-3). Insert the Model 851F into the
coupling by screwing the threaded retainer
(part of the Model 851F) into the coupling
until the gasket just starts to compress.
Tighten the retainer another 1/6 revolution
(one hex flat).

The Model 851 Transmitter can be calibrated
out-of-system.
Figure 4-2 shows an out-of -system piping
diagram.
CALIBRATION INSTRUMENTATION
NOTE – Calibration equipment should be
accurate to five times the accuracy of the
transmitter.
The Model 851 Transmitter can be calibrated
using an ammeter or voltmeter Figure 4-3.
Use an ammeter with internal shunt impedance
greater than 10 ohms will give erroneous
readings.
Use a voltmeter with a 10 ohm precision resistor
connected as shown in Figure 4-3.
1. Apply 0 psi pressure to input.
2. Adjust “Zero” pot to obtain 4mA (40 mV)
output.
3. Apply pressure which corresponds to “full
scale” pressure to input.
4. Adjust “span” pot to obtain 20 mA (200
mV) output
5. Repeat steps 1 through 4 until output
values are achieved.
6. If “span” required differs from previous
span by more than 10%, adjust
“turndown” pot prior to “span” pot and
proceed to step 4.

4-2
SECTION IV CALIBRATION
FLUSH MOUNT MODEL
1/2 NPT FEMALE
CALIBRATION FITTING
AMETEK #K900066
ZERO (FINE)
ADJUSTMENT
(+) (–)

For service:
TELEPHONE: [phone]
FAX: [phone]
E-MAIL: [email protected]
Mail, Telephone, Fax or Email orders to:
AMETEK
PMT DIVISION
820 PENNSYLVANIA BLVD
FEASTERVILLE, PA 19053
TELEPHONE: [phone]
FAX: [phone]
E-MAIL: [email protected]
for 851F flush models

U.S. GAUGE DIVISION
PMT PRODUCTS
820 PENNSYLVANIA BLVD. FEASTERVILLE PA 19053
TEL: [phone]
FAX: [phone]
E-MAIL: [email protected]