Abstract: A method of insulating a water heater with an expandable foam insulating material is provided. The expandable foam insulating material has an initial viscosity of<300 cps, a flow index.gtoreq.about 0.7, a gel index.gtoreq.about 0.8 and generates a maximum pressure of.ltoreq.about 1.0 psig. The foam is injected into the annular space between the water tank and the outer jacket. Preferably, the foam is injected into a sleeve, which acts to confine the foam during its most liquid state, positioned within this space. The foam is preferably injected into the annular space between the tank and the jacket while the top cover is removed. In this way, the injected foam can be distributed more evenly around the circumference of the tank.

Abstract: A water heater including a water tank having a jacket surrounding the tank and providing an insulation space therebetween. A plurality of serial foam injections are introduced into the space to fill the space between the tank and the jacket.

Abstract: A method of insulating a water heater with an expandable foam insulating material. The expandable foam insulating material has an initial viscosity of <300 cps, a flow index.gtoreq.about 0.7, a gel index.gtoreq.about 0.8 and generates a maximum pressure of.ltoreq.about 1.0 psig. The foam is injected into the annular space between the water tank and the outer jacket. Preferably, the foam is injected into a sleeve, which acts to confine the foam during its most liquid state, positioned within this space. The foam is preferably injected into the annular space between the tank and the jacket while the top cover is removed. In this way, the injected foam can be distributed more evenly around the circumference of the tank.

Abstract: Apparatus and method of insulating a water heater that utilizes a foaming apron comprised of substantially parallel flexible sheets having an open end and open edges. One sheet is attached to the wall of a water tank and the space between the sheets is open to receive one or more charges of foam forming liquid. Preferably one pouring is performed in conjunction with an open centering template, thereby creating a uniform sealing insulatio layer around the water tank which protects the control mechanisms from the foam. After one charge has solidified sufficiently to maintain the jacket properly centered, the centering template may be removed and one or more further charges of foam forming liquids introduced.