1. The metal tube is leaking due to corrosion, welding cracking, vibration cracking and other reasons, so we have to replace it; 2. The rubber tube is damaged and leaked due to poor temperature difference resistance and pulse pressure resistance, so we have to replace it; 3. The joint between the metal tube and the rubber tube is leaking, so we need to replace the clamp or reinstall it; 4. Check whether the warm air water tank is damaged.