The amount of airflow that reaches the hose is dependent on the efficiency of the layout of the pipe system. Lines are to be kept as straight as possible. Tight 90 degree fittings are to be used only at inlet valve locations and sweep 90's used in all other applications.
1. The Trunk Line
The trunk line connects the furthest inlet valve to the power unit. Branch lines flowing into the trunk line will connect all other inlet valves. If the basement/loft is unfinished the trunk line is best run between the joists in the basement/loft ceiling. The upper floors can be accessed through built-in cupboards, partition walls and running adjacent to soil and vent pipes. The location of the trunk line will greatly depend on the construction of the house and the location of the power unit.
2. Branch Lines
Branch lines join the remaining inlet valves to the trunk line. As with the trunk line these lines should be kept as straight as possible. Forty-five degree fittings should be used to avoid sharp corners (90 degree fittings) when possible. Airflow direction should always be considered when installing branch lines.
Avoid Gravity Drops!
A branch line located directly below an overhead trunk line will accumulate dirt due to the effects of gravity. The result will be a pile of dirt at the base of the inlet valve every time it is opened. To avoid this situation the following techniques should be used.