Classic - Airstream

Plumbing
LIQUID PETROLEUM GAS (LPG)
referred to as the by-pass flow.
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.
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 flowlimiting
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:
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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
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.
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.
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