Is the hand valve recommended for parking the trailer?

The hand valve is not recommended for parking the trailer because it can lead to a loss of air pressure. Using the hand valve to apply the brakes can cause air to bleed off from the brake system. This is particularly problematic because once the air pressure decreases below a certain threshold, the brakes can release unexpectedly, creating a hazardous situation where the trailer may roll away.

This loss of air pressure is a serious concern, especially when the vehicle is left unattended. Instead, more reliable methods for securing a trailer should be utilized, typically using the service brakes or an appropriate parking brake system designed for that purpose. By understanding the function and limitations of the hand valve, drivers can make safer choices when parking heavy vehicles.