Fluid manipulating device and tissue interacting device for a thermal therapy system

A thermal therapy system comprising:

• a device for interacting with tissue to provide thermal therapy to a structure of a therapy-receiving person's body;
• a fluid-manipulating device which heats/cools therapy-providing fluid including a pump for motivating the circulation of the therapy-providing fluid through the system and a heat exchanger for heating/cooling the therapy-providing fluid;
• tubing, and associated fittings, between the tissue-interacting device and the fluid-manipulating device;
• and
• an electrical control for controlling the temperature of the therapy-providing fluid,
• wherein the heat exchanger comprises a heat sink, a channel in a block through which the therapy-providing fluid flows, and one or more thermoelectric devices placed in thermal contact with the sink and the block,
• wherein the heat exchanger is switchable between a cold mode and a heat mode by changing a polarity of the one or more thermoelectric devices,
• wherein the electrical control is configured to automatically prevent instant switching of the polarity of the one or more thermoelectric devices, to protect the one or more thermoelectric devices from thermal shock and damage, and
• wherein in response to a command to switch polarity, the electrical control is configured to turn power to the one or more thermoelectric devices off.