Abstract: A pneumatic device for therapeutic treatment of the skin and skin pressure areas of immobile patients seated in a chair, which provides for alternating low air loss pressure sacs that are in contact with the seated patient that includes an air sac array overlay that is conveniently and quickly mounted to a bedside chair, a portable air supply that can be attached for controlling the individual air sac alternating air pressures, the portable air supply housing being mounted on the side arm of a chair, and a separate removable coverlet that is liquid impervious for incontinent patients while providing for sweat absorption for the patient seated thereon. The portable air supply can be quickly detached from the air sac chair overlay for use with a bed mattress air pressure alternating device.

Abstract: A control device for preventing freeze damage to a solar hot water heater collector and auxiliary conduits, while insuring system operation for absorbing energy whenever sufficient useable solar energy is available, thereby increasing the overall efficiency of the system. The control device includes a drain valve that may be opened as a function of ambient temperature and a drain down override circuit that insures closure of the drain down system whenever a predetermined temperature differential exists between the water in the collector and the heated water in the storage tank. The drain down will be thereby overridden in favor of increasing system energy at a predetermined temperature differential.