Off-Grid Van Conversion

A self-built campervan inspired by the farm

→ Water Heater

Mfg. / Part #: Isotemp Spa 25L Tags: plumbing


The water heater is fed by the van engine coolant system. It is tapped off of the cab air heater core in the engine compartments then the two heater hose lines are fed under the body and back into the van under the sink.

Lesson Learned: 1/2 BSP is not 1/2 NPT even though the thread pitch is close enough for incorrect fittings to fit together

Sketch of system diagram and parts:


Diagram of the coolant system and where I tapped off from the cab heater core


I installed the tank in series with the engine coolant system, adding bypass valves so we can do maintenance on the hot water system if necessary.

Coolant system install:

The manual does say to drain the tank when there is a chance of freezing, but since the tank is inside and well insulated this is unlikely at near freezing temperatures.



Next: water-pump