Maintenance For Imperial Hon 642A With Diaphragm Measuring Unit - Honeywell HON 5020 User And Maintenance Manual

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8.5.3

Maintenance for imperial HON 642a with diaphragm measuring unit

Falling components
Cleaning
Tightening torques
HON 5020 gas pressure regulator with HON 640a / HON 642a pilot
Figure
Proceed as follows:
Completing the maintenance (see page 79)
Crush and impact hazard posed by components falling or toppling over accidentally.
When working with heavy components that have been removed or are yet to be installed,
injury may result if the components start moving in an uncontrolled manner, e.g., fall down
from the working surface or topple over.
 Place removed components exclusively on level, horizontal working surfaces with enough
load-bearing capacity.
 If necessary, secure removed components so that they will not fall or topple over.
 Wear the required personal protective equipment.
 Exercise caution when performing the relevant tasks.
Observe the following cleaning instructions:
 Before assembly, all parts must be cleaned in order to remove any foreign particles
(swarf) and soiling.
 If screws, bolts, or washers are replaced with identical new parts, any oil on these new
parts must first be removed.
Observe the tightening torques below when following the instructions in this section:
Part
Closing cap
Hex nut
Hex bolt
Hex bolt
Step Description
49 Lubricate the thread surfaces.
Check to make sure that the diaphragm
marking is still in the center position (see
step 38).
Place the upper cover back in place.
Tighten the screws in a criss-cross se-
quence. Refer to the additional tightening
torque information at the beginning of this
topic.
50 Tighten the hex flange nut (1).
Screw the spring adjuster (2) back in a bit.
The correct setpoint adjustment cannot be
carried out until before commissioning
with the pilot installed.
Tightening torque
20 Nm (15 ft lbs)
12 Nm (9 ft lbs)
12 Nm (9 ft lbs)
12 Nm (9 ft lbs)
Maintenance
Step
26
28
38
42
70