I have a closed loop system, last year at this time I had some drainage tile work done in my yard and the loop was hit. It was repaired, flushed and filled to 30 psi. For the next couple of months, the pressure would drop a little, i would add a little to bring it back up to 30 psi. It finally held at 30 all summer, now with the heat running the past few months the pressure is slowly rising, up to 45 now. Would this be from the temp drop causing the loop to contract a little? thanks for any info.