Abstract: A low-cost warm water heater for use in portable toilets, to provide unblended warm water for hand washing provides a small quantity of warm water at a predetermined temperature, the flow being sensibly at ambient pressure. The water system is supplied by hand or foot pump, or gravity feed, using a low power electric immersion heater, within a small, fabricated plastic casing that is of standard fittings, solvent welded to provide a substantially vandal-proof, child-proof heater. Provision of a cold water feed with vacuum break protects the heater against being siphoned dry. Snap-in hose connections simplify assembly and maintenance. While electrically protected by the plastic case construction, electrical ground-fault protection may also be utilized. A stand-alone embodiment incorporates a diaphragm foot pump to provide spurts of warm water.

Abstract: A low-cost warm water heater for use in portable toilets, to provide unblended warm water for hand washing provides a small quantity of warm water at a predetermined temperature, the flow being sensibly at ambient pressure. The water system is supplied by hand or foot pump, or gravity feed, using a low power electric immersion heater, within a small, fabricated plastic casing that is of standard fittings, solvent welded to provide a substantially vandal-proof, child-proof heater. Provision of a cold water feed with vacuum break protects the heater against being siphoned dry. Snap-in hose connections simplify assembly and maintenance. While electrically protected by the plastic case construction, electrical ground-fault protection may also be utilized. A stand-alone embodiment incorporates a diaphragm foot pump to provide spurts of warm water.