I installed mine taking a page from theelectricbrewery.com
so order 1/2" NPT to 1/4" compression fitting
then used 2 washers to sandwich o-ring
washer (1-1/8" ID, 1-5/8" OD, 0.062" thick)
o-ring (13/16" ID, 1-1/16" OD, 1/8" thick)
washer (7/8" ID, 1-3/8" OD, 0.062" thick)
check out...