Technical Instructions
QVE1901U Flow Switch
Document Number 155-711
September 20, 2012
Page 6
Siemens Industry, Inc.
Adjust Switching
Unit
Standard Contact
The switching unit of the control switch enables two contact types:
1. Make contact (normally open):
RED arrow on the switching unit
2. Break contact (normally closed):
WHITE arrow on the switching unit
The following table explains the two contact types:
Contact Type
Setting
Flow Rate
Electric
Contact
Increasing Closing
Make contact (NO)
RED arrow
Decreasing Opening
Increasing Opening
Break contact (NC)
WHITE arrow
Decreasing Closing
The switching unit is factory set to make contact.
•
To adjust the switching unit, open the cover of the switching head.
SEN0536R1
To Open Here
Figure 10.
•
Loosen the locking screw (0.1” [2.5 mm] hexagon socket screw) and position the
switching unit until the red or white arrow is visible at the entry of the switching contact
guide to make contact or break contact, respectively.
•
You can use the arrow length to make fine adjustments to the switching point:
Adjust to the arrowhead means: Switching point is at a lower flow rate.
Adjust to the arrow end means: Switching point is at a higher flow rate.
•
Carefully retighten the locking screw.
•
It is recommended that you use Loctite to secure the locking screw of the switching unit
after carrying out individual adjustments.
•
Close the cover until it locks into place.
high flow rate
low flow rate
setting range
SEN0537R1
Make contact (Red Arrow)
Locking Screw
Red
White
high flow rate
low flow rate
setting range
Break contact (White Arrow)
Locking Screw
Red
White
