I purchased some security temp. double wall stove pipe to connect to my NC 13 and my existing class A security temp pipe/ceiling box. The problem is that the double wall pipe fits loosely at the ceiling box and at the stove. The manufacturer is telling me that's normal and I need to use pipe cement at those areas. I thought the pipe should fit snugly without any side to side movement. Is the manufacturer correct here? The old snap lock pipe that was previously used fit tightly but the pipe to pipe connections were poor.