Header, Manifold, and Vault Installation
What the exam tests
Header and manifold questions test flow balancing, vault construction, access, insulation, and freeze protection. You need to know how reverse-return headers equalize flow and how vaults protect fittings and valves.
Core rules
- Reverse-return headers give each parallel loop a similar pressure drop, improving balance.
- Direct-return headers tend to starve far loops; use balancing valves or reverse return.
- Vaults must be structurally sound, drainable, accessible, and above the water table where possible.
- Insulate exposed supply and return lines and protect them from UV and traffic.
- Provide isolation valves and drains for flushing and service.
Worked example
Four boreholes feed one vault. A direct-return header sends supply to the nearest loop first and the farthest loop last; the farthest loop sees lower flow. A reverse-return header connects supply and return in opposite order, so total pipe length and pressure drop are nearly equal. The result is better balance without adding valves. If the vault sits below the seasonal water table, it needs a sealed, structural design and a dewatering plan, not just a traffic lid.
Traps
Using a direct-return header on unequal loops; burying valves without access; placing a vault in groundwater; forgetting drains; leaving exposed pipe uninsulated.