System pressure and protection

One pressure limit

Find the lowest maximum working pressure among tank fill, pump, heater, filters, tubing, fittings, fixtures and valves. Normal and surge pressure must stay below it across temperature.

City water

Use a rated pressure regulator at the inlet and a check/backflow device. A fixed 50 PSI example exists in Shurflo's RV line, but your system limit may differ. Shut city water off when leaving the van.

Heating expansion

Water expands when heated. In a closed system with check valves, pressure can climb. The heater's relief valve and any required expansion control must be installed exactly as directed.

Water hammer

Fast-closing valves and long rigid lines create pressure spikes. Reduce velocity, support lines, use flexible pump connections/accumulator where appropriate and eliminate loose pipes.

Build rule

If you cannot reach it, isolate it, drain it and explain its pressure/temperature or water-quality job, it is not ready to hide behind a wall.

CHAPTER CHECK

• I can explain the purpose and failure mode of each item in this chapter. • I know which manufacturer limit or water-quality claim controls my choice. • I added the valve, access, drain, measurement or maintenance task to my drawing/checklist.