Vetus EXPAT075 Instructions D'installation page 3

1 Functioning
Inside the accumulator there is a membrane.
When the pump starts, water is pumped into the reservoir under-
neath the membrane. The air that is located above the membrane
in the accumulator's air chamber is compressed to the pressure at
which the pump pressostat is set. This compressed air acts as a buffer.
When opening a tap, the pressure in the air chamber ensures that wa-
ter is immediately delivered. When a tap is closed suddenly, there will
be no shock waves in the pipeline (water hammer). The accumulator
provides a constant flow of water from the tap.
2 Installation
Fitting
The accumulator tank schould be fitted in the discharge line from the
pump, as close as possible to the pump itself. Install the accumulator
before any filters or non-return valves.
Place the accumulator in a frost-free space, but away from a heat
source. For the pipeline, see fig. 1
Install
Make sure the pump is switched off and open a tap to release the
pressure of the water line.
The accumulator may be installed in any position. However, in con-
nection with the winter preparation it is recommended to install the
accumulator upright with the pipe connections at the bottom.
Connecting
Both connections are equivalent, there is no preferred IN or OUT.
• Install the hose connectors to the accumulator, see fig. 2.
Never use Teflon tape or sealing compound on the thread.
The hose connectors provided are designed with a 'taper seal' ,
creating a water tight seal when hand tightened.
• Connect the accumator with at least 30 cm (1 ft) of a good quality
reinforced flexible hose (12.7 mm, 1/2"). Avoid sharp bends and
kinks or sagging in the hose.
The reinforced hose must be of foodstuffs quality and resistant to at
least 50˚C and a pressure of 5 bar (5 kgf / cm
Vetus supplies a hose which is suitable for tap water. This hose is
tasteless, non-toxic, resistant to temperatures from -5˚C to + 65˚C.
Art.code: DWHOSE12A, drinking water hose, 12.7 mm (1/2 ") internal
diameter.
• Fit every hose connection with a good stainless steel hose clamp.
Never connect the pump directly to rigid tubing.
vetus® Accumulator
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If the system is installed using copper tubing, the accumulator
must still be connected using short sections of hose.
Pre-charge pressure of the membrane
Before use of the system, the pre-pressure of the membrane
must be set.
The accumulator comes with a pre-charge pressure of 0.7 bar. The op-
timum setting is 0.2 bar lower than the pump cut-in pressure.
For example, if the pump cut-in pressure is 1.9 bar, the pre-charge
pressure must be 1.7 bar.
• Make sure the pump is turned off and open a tap to release the
pressure of the system.
• Check the pressure with a tire pressure gauge.
Connect an air pump to the car valve to increase the pressure. Press
the valve pin to reduce the pressure.
Never use the accumulator for flammable liquids, gasoline,
diesel oil, etc.
Never exceed the maximum pre-charge pressure of 8.5 bar.
3 Winter preparation
The whole drinking water system, including the pressurized water
system, should always be drained. Never fill the drinking water sys-
tem with anti-freeze, it is very poisonous!
4 Trouble shooting
Pressurised water pump cuts in & out rapidly when outlet is
partially open.
- Pressure in accumulator tank incorrect > Check tank pressure and
adjust.
- Accumulator tank membrane split > Replace tank.
Schräder valve leaks.
- Expansion tank membrane split > Replace tank.
Note: Spare parts are not available. A defective accumulator must
be replaced in its entirety.
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