Airstream CLASSIC TRAILER - Manual (Page 62)

F
PLUMBING SYSTEMS
LIQUID PETROLEUM GAS (LPG)
FILL VALVE
Your trailer is equipped with LP tank fill valves called
“RV Type I Acme” connection. The large, green, nylon
swivel nut is a right hand thread and is designed for
hand operation only.
The valve features an internal spring-loaded module
that will not allow gas to flow from the cylinder until
a positive seal has been made at the connection. The
valve outlet has 1-5/16” Acme threads on the outlet
exterior and female POL, left-handed threads on its
interior. This feature allows for connection of the new
wrenchless, right-handed, Acme RV connection and
still accommodates the standard left-handed POL
fittings used for filling propane cylinders.
The mating, green swivel nut and brass nipple also
incorporates new features: the green nylon nut swivels
on a black bushing that is heat sensitive. Between 240
degrees F. and 300 degrees F. the bushing will yield
(melt) allowing the spring-loaded module in the valve
to push the brass nipple back (approximately 1/4”)
closing the module and stopping the flow of gas from
the cylinder. Inside the brass nipple is a flow-limiting
device designed to sense excessive gas flow. If an
excessive flow is sensed, the flow-limiting device shuts
the flow down to a maximum of 10 SCFH (Standard
Cubic Feet per Hour) or less. This is also referred to as
the by-pass flow.
By-pass flow is extremely important in the proper
operation of this connection. The flow-limiting device
may activate if the cylinder valve is opened quickly.
When all appliances are off, the by-pass flow allows
the pressure downstream from the flow-limiting device
to equalize. When pressure is equalized, the flow-
limiting device will supply normal flow to the system.
Equalization occurs in approximately 5 seconds and in
most cases goes completely unnoticed. If, however, an
appliance is left on or there is a leak or open flow in
the system, the by-pass pressure will not be able to
equalize and allow the flow-limiting device to re-open.
Symptoms of this condition would be appliances that
light but have lower than normal flame or starve out
from lack of gas, a substantial reduction in the flame
when another appliance is operating, or pilots that are
difficult to light. If this should happen, the following
steps should eliminate the condition:
1. Close LP cylinder valve.
2. Extinguish all flames and smoking materials
3. Be sure all gas appliances, including their pilot
lights, are off.
4. Open LP cylinder valve slowly. DO NOT
SNAP OPEN.
5. Wait at least 15 seconds before lighting appliances.
6. If operational difficulties continue, there may be
a leak in the system. Immediately close the LP
cylinder valve and have the system inspected by a
qualified RV service technician.
Again, make sure all appliances are off before
opening propane cylinder valves.
Exception: when reconnecting a full cylinder to an auto
changeover regulator it is not necessary to shut off the
appliances or close the valve of the cylinder already in
service.
WARNING : LEAKING LP GAS MAY IGNITE
CAUSING A FIRE OR EXPLOSION WHICH COULD
RESULT IN SERIOUS BODILY INJURY, PROPERTY
DAMAGE, OR DEATH.
How long a full tank of gas will last is dependent on
usage. In cold weather, when you are using the furnace,
large amounts of hot water, and are doing extensive
cooking, you will naturally use more than you will in
warm weather when you may do limited cooking. On
the average, with normal cooking and other appliance
use you can probably count on two to three weeks of
service from each tank.
PLUMBING
F - 1