Thrush AHF Series - Manual (Page 16)

Section 5
Maintenance Information
5.1 Maintenance Information
The Aar-O-Vent’s simple design allows for minimal maintenance. There are no moving
parts other than the air elimination device itself.
 Routine flushing of the blow down valve and skim valve are recommended.
Frequency of flushing is system specific based on water quality. A container or
hose should be used to catch the sediment when flushing the valves, unless they
are piped to an adequate drain.
System water over 100°F can be very hazardous. Keep flow away from the body
when flushing the unit. Failure to do so could result in serious bodily injury or
property damage.
 The coalescing medium (bundle) can be removed for cleaning as needed. A
power washer or hose is sufficient. The stainless steel construction allows for
ease of cleaning. A new gasket should be installed upon reassembly of the unit.
Tighten all bolts in a criss-cross fashion, properly torqued. See chart below.
Depending on the size of Aar-O-Vent, the head and bundle can be quite heavy. It is
recommended that supports be used when removing the head/bundle. Once all
bolts have been removed from the head, the head and bundle are free to drop.
Risk of severe personal injury and/or property damage may occur if the bundle
and head are not properly supported.
 When replacing the gaskets and reassembling the unit, the bolts should be
torqued incrementally to 30%, 60% and then 100% of the appropriate value
shown in the chart below. They should also be torqued in a criss-cross pattern.
Aar-O-Vent
Connection size
Removable
Head Size
Bolt Size Number of Bolts
Torque Ft/Lb
(150# Flgs.)
2” 6” 3/4” 8 50
2.5” 6” 3/4” 8 50
3” 6” 3/4” 8 50
4” 8” 3/4” 8 50
5” 10” 7/8” 12 80
6” 12” 7/8” 12 80
8” 16” 1” 16 123
10” 20” 1 1/8” 20 195
12” 24” 1 1/4” 20 273
Thrush Co.
Manual #9636-1230