Due to physical and chemical properties of the agent, pressure in the tube can vary depending on the ambient temperature. The higher the ambient temperature, the higher pressure in the tube and vice versa. At very low temperatures, the pressure gauge can be seen near zero due to the low pressure of agent vapours.
When checking the pressure gauge during or after a engine running the Gauge may be showing closer the the red zone. This is not a problem as long as your enclosure is not exceeding 105 degrees Celcius.
The Indicator on the pressure gauge can vary from 0 bar (0 psi) when temperatures are very low to 17 bar (247 psi) when temperatures are very high. This is not a sign of defect in the system.
See our video for the inspection of the T series for further details