Project Overview: Streamlining Hot Water Delivery with Precision Engineering

In this Nanaimo home, we retrofitted a John Wood tank heater with a recirculating pump and expansion tank, creating a closed-loop system that circulates water via gravity and pump-assisted flow to eliminate cold water purging. The process began with hydraulic balancing to match pump capacity (typically 0.5-1 GPM) with pipe diameters, ensuring laminar flow without erosion. We integrated a thermal switch that activates the pump only when water temperature drops below 95°F, interfaced via low-voltage relays to prevent constant runtime and optimize energy use.

Technically, installation involved soldering copper fittings for the return line, pressure-testing at 80 PSI to detect leaks, and calibrating the expansion tank's pre-charge (usually 12 PSI) to absorb thermal expansion and prevent water hammer. The pump's impeller was aligned for minimal cavitation, and electrical continuity was verified with a megohmmeter to confirm insulation resistance above 1 MΩ, safeguarding against faults in damp environments.