I have a Weil Mclaine boiler. I brush it out annually then pull the burner and sweep out the debris that falls into the fire box. Each year the liner (wet pack) has more areas of thinning or concern. I found the replacement part numbers but how do I install the pack? Do I simply wet it and place it. Do I somehow glue it in? I am referring to the floor and rear refractory.. maybe even the front also. I have had the boiler apart but have not removed the old pack or ordered the parts yet. Product diagram http://www.weil-mclain.com/professionals/services/discontinued/68.pdf