It will take about 2 months to warm it up, fix the problem, and cool it down again. In about 2 months, they are shutting down for the winter, to save on electricity costs (power's more expensive in the winter), and to allow more work to be done on the equipment (the magnets need to be trained up to full strength, for one). It's either not possible to get it up and running again before the scheduled shutdown, or not worth the expense of doing so for such a short period of operation...and by not doing so, they can spend the cooldown/warmup time that would be required doing more useful work on the accelerator.