A fluid circulating apparatus for warming or cooling a surface includes a pressurized fluid source operative to circulate fluid through a conduit such that a supply fluid moves from a supply port of the fluid source into a first end of the conduit, through the conduit, and from a second end of the conduit to a return port of the fluid supply. A flow control when in a forward mode directs fluid from the supply port into the first end of the conduit and from the second end of the conduit to the return port, and when in a reverse mode directs fluid from the supply port into the second end of the conduit and from the first end of the conduit to the return port. A mode selector is operative to switch the flow control between forward mode and reverse mode.