Vacuum-Purged Domestic Tank
Please read this before initial LP-Gas Fill
Thompson's Vacuum-Purged Domestic Tanks have been purged of air in accordance
with NPGA standards. The valves have been equipped with tamper evident seals.
The container must be repurged if the tamper evident seals have been violated.
An improperly purged container can cause an increase in pressure, improper
burning fuel mixture and odorant fade--any of which can result in personal
injury, property damage, or death.
Verifying the Vacuum
It's important to first verify that a vacuum is present. First, remove the green
plastic wrap from the service valve and verify that the hand wheel is closed.
Connect a vacuum pressure gauge to the service valve outlet connection and open
the hand wheel. Visually check the vacuum pressure gauge dial for evidence of a
vacuum. Next, after closing the service valve, disconnect the vacuum gauge. If
the vacuum does not meet NPGA safety standards, the container must be repurged.
Methanol Injection
Before filling the container with LP-Gas, you must inject methanol through the
service valve outlet connection. Afttach the POL connection to the service outlet
connection. The POL connection should have a lower pressure rubber hose extend
into a container of methanol.
Next, open the service valve slowly, allowing the vacuum to draw methanol into the
vessel. If the methanol container is allowed to run dry, air will be drawn into the
vessel.
NOTE: Even if a vacuum is present methanol still needs to be introduced into the container.
To neutralize moisture in an ASME container, introduce at least one pint of genuine
anhydrous methanol (99.85% pure) for each 100 gallons of water capacity.
LP-Gas Injection
Once the methanol has been injected, use a hose to join your LPG source to the POL
connection of the service valve. This hose can be employed as a means of injection
for either liquid or vapor product into the vessel. The amount of LP-Gas needed to
neutralize the vacuum pressure will vary depending upon the vessel's volume. For
liquid, 1-4 gallons of LP-Gas is necessary for all vessels up to 1,000 wg. For vapor,
wait until there is no detectable audible transfer of vapor from the LP-Gas source to
the vessel.
Filling
Once the LP-Gas injection is complete, close the service valve and disconnect the POL
connection. Remove the red plastic wrap from the filler connection, remove the yellow
cap and connect your filler hose to the vessel and then fill in the normal manner.