1+ Dump valve  
2+ Breather hose  
3+ Vacuum hose  
4+ Air switching valve  
5+ Hose  
6+ Hose clip  
7+ Air pipe  
8+ Stub pipe hose  
9+ Delay valve  
10+ T-piece  
11+ Double pipe clip  
12+ Vacuum regulator  
13+ Vacuum stepped hose  
14+ Thermal vacuum valve  
15+ Vacuum control valve  

The part numbers in the assembly image below relate to the product number in the table. Clicking on the part number will open up the relevant part details.