| 摘要 |
<p>Solar-heat circuits having a drain-back system can freeze during filling of a line section which is arranged in the exterior region, although a high temperature prevails in the solar collector. This freezing is to be prevented. The method according to the invention comprises activation of a pump starting program in the case of a pump activation. Said program comprises stipulation of a fluid quantity to be delivered; a fluid introduction sequence, containing the delivery of the stipulated fluid quantity from a first line section into an unfilled second line section in the exterior region; and a fluid return sequence, containing determination of a return temperature of the returning fluid. Subsequently, the stipulation of the delivery quantity is increased and either the above-mentioned steps are repeated if the return temperature is greater than or equal to a limiting return temperature and the increased stipulation of the fluid quantity to be delivered is less than or equal to a limiting quantity; or the pump starting program is deactivated and standard operation of the pump is started if the increased stipulation of the delivery quantity is greater than the limiting quantity; or pump starting program and pump are deactivated and the stipulation of the fluid quantity to be delivered is reset if the return temperature undershoots the limiting return temperature.</p> |
