SD66
5
Calibration
The only calibration adjustment for the relay is the adjustable exhaust seat which sets the output span. This
adjustment must be made if the relay has been disassembled for parts replacement, ratio change, etc.
Equipment Required:
•
Regulator and test gauge for setting supply air
•
Regulator and test gauge for adjusting input
•
Output test gauge
•
1/16" Allen wrench
Procedure
1.
Connect supply regulator and test gauge to the supply connection (see Figure 1).
2.
Connect the input regulator and test gauge to input connection.
3.
Connect output test gauge to output connection.
4.
Turn on supply air.
5.
Exercise the relay by adjusting the input regulator as follows:
Amplifying Relay — Lower input range value to upper input range value.
Reducing Relay — Upper input range value to lower input range value.
6.
Check the output span while exercising the relay. If the output span is too small, turn the exhaust seat
counterclockwise. If the output span is too great, turn the exhaust seat clockwise.
NOTE
To gain access to the exhaust seat, turn off the supply air. Refer to the Parts List and
remove the retaining nut, plunger and plunger spring.
7.
Insert a 1/16" Allen wrench through the exhaust port in the bottom forging; make adjustment.
8.
Install plunger, plunger spring, and retaining nut.
9.
Repeat steps 4 through 8 until span is set.
Function and Ratio Change
The function and/or ratio of a Relay can be changed using standard parts.
•
To change the function from amplifying to reducing or vice versa with the same ratio (e.g., Model 66BA2 to
Model 66BR2), reposition the diaphragm ring and replace the output diaphragm assembly.
•
To change the input-to-output ratio (e.g., Model 66BA2 to 66BA4) or both the function and ratio (e.g., Model
66BA2 to 66BR4), replace the diaphragm ring and output diaphragm assembly.
Parts Determination
1.
Refer to the Model Designation and locate the Model Number of the relay with the desired function and input-
to-output ratio. This Model Number will, in effect, be the new Model Number of the relay after the change.
2.
Refer to Table 2 and locate the new Model Number. Read straight across and obtain the diaphragm ring and/or
output diaphragm assembly part numbers as required.
3.
Refer to the Parts List for ordering information.
Procedure
1.
Refer to Parts List. Remove top forging, input diaphragm, diaphragm ring, and output diaphragm assembly.
2.
Install the new output diaphragm assembly.
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