Robertshaw CR-103-A Series User manual

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INSTRUCTION MANUAL
FOR
Averaging Relay
CR-103-A
INSTRUCTION MANUAL NUMBER
P-2172
Rev. A
Note to installer: Before installing, read instructions carefully and record
model number. After installing, give this manual to operating personnel o
r
see that it is filed for future reference.
1602 Mustang Drive
Maryville, Tennessee 37801
Phone: [phone] Fax: [phone]

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NOTES:

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A. DESCRIPTION:
The Model CR-103 Averaging Relays are proportioning units
designed for use in industrial pneumatic control systems
where the application requires averaging 2, 3, 4, 5, 6 or 7
input pressure signals to obtain one output pressure signal.
For example: Where two or more transmitters (or controllers)
are measuring a common variable, the output pressures of the
transmitters (or controllers) can be averaged according to the
equation:
Output pressure
of Averaging Relay
Unused ports must be left open to atmospheric pressure.
B. DESIGN DATA:
INPUT PRESSURE RANGE:
0 to 20 psig (0 to 1.4 bar) nominal
50 psig (3.5 bar) maximum
OUTPUT PRESSURE RANGE:
0 to 20 psig (0 to 1.4 bar) nominal
50 psig (3.5 bar) maximum
SUPPLY PRESSURE: ....................30 psig (2.1 bar) nominal
60 psig (4.2 bar) maximum
(Should always be at least
10 psig (0.7 bar) greater
than output pressure.)
BIAS ADJUSTMENT:............ ±18 psig (1.2 bar) divided by
the number of input signals
OVERLOAD PROTECTION:.........100 psig (7 bar) will not
damage unit
AMBIENT TEMPERATURE LIMITS: ..... -40°F to 180°F
(-40°C to 82°C)
CONNECTIONS:......................... 1/4" female NPT for input,
output and supply
WEIGHT:
2 input signals ..............................................2 lb. (0.91 kg)
7 input signals ...........................................3.5 lb. (1.59 kg)
C. PERFORMANCE DATA
ULTIMATE SENSITIVITY:...................0.1% of full range
LINEARITY:................................................1% of full range
HYSTERESIS: .............................Less than 1% of full range
REPEATABILITY: ..................................0.5% of full range
SUPPLY PRESSURE EFFECT:
Change in output pressure for 5 psig (0.35 bar)
supply pressure change, less than 1% of full range
AMBIENT TEMPERATURE EFFECT:
Change in output for a 75°F (24°C) ambient
temperature change, 0.5% of full range
AIR CONSUMPTION:.........................6.0 SCFH maximum
FOR MAXIMUM FLOW:
Supply Output Capacity .....................3.0 SCFM nominal
Exhaust Output Capacity ...................3.0 SCFM nominal
D. MODEL NUMBER DESCRIPTION:
MODEL NUMBER INPUT
CR103-A2 2 Signals
CR103-A3 3 Signals
CR103-A4 4 Signals
CR103-A5 5 Signals
CR103-A6 6 Signals
CR103-A7 7 Signals
SECTION I - GENERAL INFORMATION
Sum of input pressure signals
±
spring bias
=
Number of input pressure signals

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A. GENERAL:
Be sure that all pipes and fittings used are clean, free of chips,
dirt and moisture. If pipe compound or shellac is used, apply a
small amount above the second or third male thread only.
DO NOT GET PIPE COMPOUND OR SHELLAC INSIDE
RELAY.
B. MOUNTING:
When installing the relay, do not remove the plastic plugs from
the connections until ready to install fittings. Do not remove
any metal pipe plugs.
The relay may be mounted in any position. Due to its size and
OPERATION:
The illustration (Figure 2) shows a relay for averaging 7 input
pressure signals. The operation of the smaller units is similar.
With zero input pressure at all input ports and the biasing
spring adjusted so that it is not exerting any force in either
direction, the unit is in a balanced position. In this balanced
position, both the supply and exhaust seats of the valve are
closed and there is no air flow. The diaphragm areas are
related in such a manner that the effected force of any input
pressure is downward. Therefore, with the unit in a balanced
position, introduction of any input pressure will create a
downward force which will move the center assembly down,
opening the supply seat of the valve and permitting supply air
pressure to flow into the output chamber. This output pressure
is channeled into all of the balancing chambers. The
diaphragms of the balancing chambers are related so that this
output air pressure creates an upward force. As the output
pressure approaches the average input pressure, the center
weight, it may be supported by the air lines. If more secure
mounting is desired, use the mounting bracket furnished as
shown in Figure 1. Use two 1/4" bolts, toggle bolts or wood
screws as required by the installation. Bracket may be
removed or inverted by removing two lock nuts.
C. CONNECTIONS:
The input, supply and output ports are 1/4" female NPT.
Make the air connections to the proper ports as shown in
Figure 1. The air supply must be clean, dry and regulated
(use filter-regulator #97478) and must not exceed 60 psig (4.2
bar).
assembly will be returned to the balanced position, permitting
the supply seat of the valve to close, throttling the flow of
supply air.
Should any or all of the input pressure decrease, the upward
force of the output pressure would be greater than the
downward force of the input pressures. Then the center
assembly would move upward, opening the exhaust seat and
thereby exhausting the output air until the decreased output
pressure again balances the input pressures.
The spring assembly permits biasing the output pressure to a
maximum of ±18 psig (1.2 bar) divided by the number of
inputs. In the 6 input signal relay, this means that the output
pressure may be biased ±3 psig (0.21 bar). In the 2 input
signal relay, it may be biased ±9 psig (0.62 bar). This is
accomplished by turning the adjusting screw in the top of the
assembly to either extend or compress the spring.
SECTION II - INSTALLATION
SECTION III - OPERATION
Figure 1
NUMBERED PORTS ARE INPUT SIGNAL
CONNECTIONS
DIMENSIONS
MODEL NO. A B
CR103-A2 4-7/8″
(124 mm) 4″ (102 mm)
CR103-A3 5-3/8″
(137 mm) 4-1/2″ (114 mm)
CR103-A4 5-7/8″
(149 mm) 5″ (127 mm)
CR103-A5 6-3/8″
(162 mm) 5-1/2
(140 mm)
CR103-A6 6-7/8″
(175 mm) 6″ (152 mm)
CR103-A7 7-3/8″
(187 mm) 6-1/2″ (165 mm)
SIGNAL PORT 5 IS ON THE FACE OPPOSITE
PORT 7
DIMENSIONS

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A. BIAS ADJUSTMENT:
With normal supply pressure and input (signal) pressures
applied, the Bias Adjusting Screw (Figure 2) may be turned
clockwise to increase the output (control) pressure or turned
counterclockwise to decrease output pressure.
B. RATIO ADJUSTMENT:
This is not a normal operating adjustment. However, when
necessary, the ratio of input to output pressure may be adjusted
by adjusting Valve Seat (17) as follows (see Figure 3 except
where noted):
1. With a supply pressure of 30 psig (2.1 bar) and an input
pressure of 3 psig (0.21 bar) on each input port, turn Bias
Adjusting Screw (Figure 2) until output pressure is 3 psig
(0.21 bar). Increase all input pressures to 15 psig (1.03
bar) and check output pressure, which should be 15 ±0.2
psig (1.03 ±0.01 bar).
2. If necessary, remove Cap (24) and adjust Valve Seat (17)
until the correct output pressure is obtained.
3. Repeat steps 1 and 2 until the correct ratio is obtained.
This unit may be adjusted while operating with Cap (24)
removed, but the final setting must be checked after the
Cap (24) has been replaced.
Figure 2
The simplified design of this relay makes routine
maintenance unnecessary. However, should the air or air
lines be dirty, it may be necessary to clean the surfaces of the
Valve (18) and the Valve Seats (A) and (B). If continued
difficulty is experienced from dirt, moisture, oil, etc., suitable
filters should be provided in the supply lines.
If the control pressure does not go to minimum output
pressure or zero, or if the exhaust appears to be leaking,
follow the instructions below (refer to Figure 3 except as
noted):
1. Remove the Cap (24) and Spring Retainer (20) by
unscrewing from the Cover (22). Note position of
Spring Retainer (20) before removing so that it can be
replaced in approximately the same position. The Valve
(18), Valve Spring (19) and Gasket (23) are now free to
fall out. Be careful not to drop the parts.
2. Using a CLEAN, soft brush, cloth or paper, wipe off the
Valve Seats (A) and (B).
3. Inspect both Hemispherical Surfaces (C) of the Valve
(18) for dirt, chips, etc. If any scars or imperfections are
apparent, the Valve (18) should be replaced.
4. Replace the Valve (18), Valve Spring (19), Spring
Retainer (20), Gasket (23) and Cap (24). Be sure that the
Spring Retainer (20) is in the same position as it was in
before disassembly, approximately one turn below being
flush with end of Adjustable Seat (17) and that the Cap
(24) is tight. Check Cap (24) for external leakage.
5. Adjust per Section IV if needed.
DO NOT USE ANY GASKET SHELLAC, PIPE
COMPOUND, OR OTHER SEALANT.
SECTION IV - ADJUSTMENTS
SECTION V - MAINTENANCE

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.
If the procedure outlined in Section V (MAINTENANCE)
fails to restore proper operation, it is recommended that the
relay be returned to the factory for repair due to the critical
orientation of the components. Contact the factory or a factory
representative for instructions on returning the relay.
If the relay is to be repaired in the field the order in which the
plates and gaskets were assembled, and the orientation of those
parts, must be noted so that they may be reassembled correctly.
Repair kits are available as specified below.
To repair the relay, disassemble the relay as shown in Figure 4
(except as noted) and follow the instructions below:
1. Inspect air passages for dirt.
2. Inspect the Valve (18) surfaces for bumps, scars or other
irregularities. The Hemispherical Surfaces (C in Figure
3) must be smooth and regular.
3. Inspect the Valve Seats (A and B in Figure 3). The
surfaces must be clean and smooth with no scars or
surface irregularities.
4. Inspect Diaphragms (29 for holes or worn spots which
might permit air leakage.
5. Install the Valve (18), Valve Spring (19) and Spring
Retainer (20) and make sure that the Valve Spring (19) is
seating the Valve (18) properly.
6. Replace any worn or defective parts and reassemble the
relay.
DO NOT USE ANY GASKET SHELLAC, PIPE
COMPOUND, OR OTHER SEALANT.
7. With Supply and Input air pressures connected, check the
unit for external leakage.
8. Follow procedure in Section IV (ADJUSTMENTS).
CAUTION: If cleaning is required, do not subject the
Diaphragms or Gaskets to cleaning fluids or solvents.
REPAIR KITS
RELAY
MODEL NO.
REPAIR KIT
PART
NUMBER
CR-103-A2 083405B0006
CR-103-A3 083405B0005
CR-103-A4 083405B0004
CR-103-A5 083405B0003
CR-103-A6 083405B0002
CR-103-A7 083405B0001
SECTION VI - REPAI
R
Figure 4

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REPAIR PARTS
ITEM DESCRIPTION PART NUMBER QUANTITY
1¼HEX NUT, 1/4-28 036602A1800 1
2¼SEALING WASHER 037723A0001 1
3 COVER 027930B0001 1
4 ADJUSTING SPRING ASSEMBLY 081249A0001 1
5 WASHER 027947A0001 1
6 HEX NUT, 1/4-20 027939A0001 1
7 WASHER 027946A0001 1
8¼GASKET 028566A0001 1
9 STEM 028559A0001 1
10 SPACER 029707B0001 1
11¼O-RING 036240N0010 1
12 MULTIPLE INPUT CASE 028562A0001 1
13¼GASKET 028567A0001 1
14 TRANSFER PLATE 029716A0001 1
15 TOP SPACER 028555A0001 1
¼VALVE ASSEMBLY (contains items 16 thru 22) 081650A0001 1
16 O-RING 036240N0014 1
17 ADJUSTABLE SEAT 029352A0001 1
18 VALVE 026059C0001 1
19 VALVE SPRING 029359A0001 1
20 SPRING RETAINER 029354A0001 1
21 O-RING 036240N0018 1
22 VALVE COVER 029353A0001 1
23¼GASKET 029356A0001 1
24¼CAP 029355A0001 1
25¼O-RING 036240N0119 1
26 TUBE SEE TAB 1
27 EXHAUST RING 029715A0001 1
28 DIAPHRAGM RING 031766A0001 SEE TAB
29¼BALANCING DIAPHRAGM 028561A0001 SEE TAB
30 EXHAUST PLATE 027929A0002 2
31 PRESSURE PLATE 028571A0001 SEE TAB
32 PRESSURE PLATE 028569A0001 SEE TAB
33¼EXHAUST SEAT 028557A0001 1
34 SUPPORT RING 028565A0001 1
35 BASE 027668C0001 1
36 SCREW SEE TAB 4
37 HEX NUT, KEPS, 1/4-20 (not shown) 036603A0019 2
38 MOUNTING BRACKET (not shown) 029139A0001 1
39 PIPE PLUG, 1/4 NPT (not shown) 028564A0001 SEE TAB
40 PIPE PLUG, 1/16 NPT (not shown) 525GD001 1
Note: Repair kits are available for rebuilding relay.
Repair kits contain parts marked thus ¼.
TABULATION
DETAIL
MODEL 26 28 29 31 32 36 39
CR-103-A2 028556A0006 3 reqd 5 reqd 2 reqd 036617E3600 5 reqd
CR-103-A3 028556A0005 5 reqd 7 reqd 4 reqd 036617E3800 4 reqd
CR-103-A4 028556A0004 7 reqd 9 reqd 5 reqd 1 reqd 036617E3900 3 reqd
CR-103-A5 028556A0003 9 reqd 11 reqd 7 reqd 1 reqd 036617E4000 2 reqd
CR-103-A6 028556A0002 11 reqd 13 reqd 8 reqd 2 reqd 036617E4100 1 reqd
CR-103-A7 028556A0001 13 reqd 15 reqd 9 reqd 3 reqd 036617E4200

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U.S.A and Canada
Robertshaw Industrial Products Division
1602 Mustang Drive
Maryville, Tennessee 37801
Telephone: [phone] Fax: [phone]
http://www.robertshaw.thomasregister.com
http://www.robertshawindustrial.com
Exports
Invensys Appliance Controls
1701 Byrd Avenue
P.O. Box 26544
Richmond, Virginia 23261-6544
Telephone: [phone] Fax: [phone]
Q-1343 (11/04) Printed in U.S.A.