Most dormakaba door closer systems with hydraulic damping have thermo-constant valves allowing temperature fluctuations between -25 °C and 40+°C.
These will expand in the heat as the viscosity of the oil changes and becomes more free-flowing. In the cold, they will contract and allow the passage of oil a greater ability to flow unhindered, thus maintaining the correct speed control at all times.
HOWEVER –
The manufacturer of the door closer considered employing the door closer under the following foreseeable conditions as MISUSED.
- excessive heat (over 40 °C) or,
- excessively low temperatures (below –15 °C).
