Multiaqua MAC-036HE, Installation And Operation Manual

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Expansion Tanks
Liquid solution expansion and contraction within the closed system must be
compensated for with an expansion tank. The expansion tank used with the
Multiaqua system is a steel tank with a rubber bladder internally attached.
There is air pressure on one side of the rubber bladder that keeps the bladder
pushed against the sides of the tank before the system is filled with liquid
solution (illustration above). As the liquid solution heats up, the bladder will be
pushed further away from the tank walls allowing for expansion and
contracting as the liquid solution temperature changes. By flexing, the bladder
controls the system pressure adjusting to temperature variations of the chilled
liquid solution system.
It is critical that the expansion tank's air bladder pressure be less than the
system solution pressure.
Air pressure can be measured with an automotive
tire gauge at the Schrader valve port on the expansion tank. Bleeding air out of
the bladder or increasing the pressure with an air pump will adjust the pressure.
Filling System with Liquid Solution
Before filling the system with liquid solution (Propylene Glycol and water),
pressure test the piping system with compressed air.
Testing should be done
at a maximum of 50 PSI . The system should hold air pressure for a minimum
of one (1) hour with no leakage.
Concentrations of Propylene Glycol in excess of 50% will destroy o-rings in
fittings and pumps. Water should be added to the system first or a solution of
diluted Propylene Glycol mix.
System that contains 50 or more U.S. gallons should have a tee fitting with a stop valve
installed in the return line close to the chiller. The stop valve can be opened and attached to a
hose with a female by female hose fitting. In the open end of the hose section (1 - 1.5 feet
long) insert a funnel and pour the liquid solution mixture or add water first and then the
appropriate quantity of Propylene Glycol (refer to Table 6). After adding the liquid solution
mixture, proceed to add enough water to the system to achieve 15 PSI gauge pressure. To
measure system pressure, shut off the stop valve, remove hose, and attach a water pressure
gauge. Open the stop valve and read system pressure. Systems that use a chilled liquid
solution storage tank should be filled at the tee/stop valve fitting in the outlet fitting of the
storage tank.
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