DeZURIK
APCO DAT Double Acting Throttling Device
D12029
Page 4
June 2014
Adjustment
See Figure 1 for part identification.
The setting on the Double Acting Throttling Device must be tolerable to the collapsing
pressure on the system.
Confirm that the DAT is firmly screwed to the valve outlet (top).
To adjust the DAT, close the Teflon plug (5) by turning the adjustable stem (3)
clockwise
to be fully
extended. Note that the device is designed so as it cannot completely close. Open the Teflon plug by
turning the adjustment stem
counter clockwise
, three (3) full turns.
Start pump. Listen and observe the Air/Vacuum Valve closing when water column reaches the valve. If
the valve gently closes and no surge is apparent, lock the position setting in by turning the lock nut (6)
against the cover (2).
If there is a "thunk" when valve is closing, turn the adjustable stem (3) one full turn
clockwise
to farther
close the devise and restrict the amount of air evacuating. Depending on the application, more than one
turn towards the closed position may be necessary. This will establish a back pressure on the rising
column of liquid to reduce shock, pressure surge and water hammer to the system.
NO DESCRIPTION
1 Housing
2 Cover
3 Adjustable Stem
4 Spring
5 Plug
6 Lock Nut
7 Nipple
Figure 1: DAT Double Acting Throttling Device