Abstract: A container or reservoir for liquid to be heated, has a pump well and heater assembly secured to and depending from the bottom wall of the container, and a pump and pump tube assembly can be positively locked on the well for pumping function but is easily and quickly removable for cleaning or replacement. The assembly is locked on the well by a retainer plate fixed to an outer pump tube and having locking portions coactive with locking portions on the side wall of the well, with said outer tube being telescopically slidable and rotatable on an inner pump tube which carries a pump plate to seat in the well and a valve disk co-operative with said valve plate. A compression spring is disposed between the retainer plate and the pump plate locking portions to hold the retainer plate interlocked with the well locking portions and to hold the pump plate seated in the well.