Appendix A - Technical Reference
150-712-200-02
36
July 26, 2000
HRE-712 List 1 and List 2
Replacing the Breather-Vent Valve
The Breather-vent Valve (BVV) is an all-metal, nickel plated brass unit shown in
. The BVV
allows air to circulate into the enclosure so it can breath and avoid the build up of excessive moisture and other
contaminates. It has a hollow threaded stem that connects into a brass fitting located at the bottom of the base. An
O-ring is located on its outer threaded stem that connects to the brass fitting. The hollow stem contains a piece of
plastic screen to prevent insects from migrating into the enclosure.
To remove and replace the breather vent:
1
Grip the BVV with a
3
/
4
-inch wrench and loosen by turning it counterclockwise, then remove the valve by
hand.
2
Verify that the new BVV is equipped with its O-ring.
3
Thread the BVV into the brass fitting. Do not crossthread.
4
Grip the BVV with a
3
/
4
-inch wrench and tighten the valve to 60 inch-pounds of torque. Do not overtighten.
Excessive torque does not improve the seal and may damage the PCV.
Replacing the Air-Stem Valve
The Air-stem Valve (ASV) is part of an all metal, nickel plated brass assembly shown in
. The
ASV pressurizes the enclosure from an external air supply or release the internal pressure.
The assembly consists of an adapter that screws into a brass fitting located at the bottom of the base. The ASV
itself, which screws into this adapter and the cap, connects to the top of the ASV. The adapter has two O-rings that
are required to create an airtight seal. One is located on its outer threaded stem that connects to the brass fitting;
the other is located at the base of its inner well where it seals the ASV to the adapter.
To remove and replace the ASV, proceed as follows:
1
Grip the adapter nut with a
3
/
4
-inch wrench and the ASV with a
7
/
8
-inch wrench.
2
While holding the adapter nut steady (it should not be moved), loosen the ASV by turning it counterclockwise
and then remove the valve by hand. If the adapter nut becomes loose, tighten it to a torque of 60 inch-pounds.
3
Check that the O-ring in the adapters inner well has remained in place. If not, reseat it.
4
Thread the new ASV into the adapter. Do not crossthread.
5
Grip the adapter nut with a
3
/
4
-inch wrench and the PRV with a
7
/
8
-inch wrench and tighten the latter to
120 inch-pounds of torque. Do not overtighten. Excessive torque does not improve the seal and may damage
the PCV.
6
Pressurize the chamber and check entire assembly for leaks.
The identical ASV is used in the Air-stem/Air Inlet T-valve assembly. Only the ASV in the
T assembly may be replaced.
