Precharge Pressure - Grundfos GT-C Installation And Operating Instructions Manual

Installation of the tank with a plastic base
4.2.2 Wall installation
Small GT tanks up to 35 litres must be secured to a
wall or similar.
Example of wall installation with a wall bracket
(product no. 00ID9070)

4.3 Precharge pressure

The GT tanks are supplied from the factory with a
precharge pressure. See tank nameplate.
The precharge pressure must be adjusted according
to the actual application and the installed pump.
The precharge pressure must be slightly below the
pump cut-in setting.
Recommended precharge pressures:
• 0.9 x setpoint for fixed-speed pumps
• 0.7 x setpoint for variable-speed pumps.
8
Precharge pressure
4.3.1 Adjusting the precharge pressure
Before starting work on the product, make
sure there is no system pressure on the
tank.
Disconnect pumps or switch off the power
supply.
If the precharge pressure is not suitable for the
application, adjust it as follows:
1. Switch off the pump. Open the nearest tap to
make sure that no system pressure is affecting
the reading.
2. Remove the protective cap.
3. Check the precharge pressure with a suitable
pressure gauge.
4. Release or add air as required to make the
precharge pressure equal to the recommended
precharge pressure.
5. Fit the protective cap to prevent air from escaping
from the tank.
Never exceed the maximum operating
pressure of the tank.
4.3.2 System check
The GT tank must be bypassed if the system
pressure exceeds the maximum operating pressure
of the GT tank during a system check.
4.3.3 Isolating valves
We recommend installing an isolating valve in
connection with the GT tank.