I looked at the construction sub-forum for insight, and did an "open forum" search for answers to my question, but drew a blank. I am contemplating an "upgrade" to my pump-house, to get rid of all the old brass valves, iron unions and excess 90* bends in the plumbing. To accomplish this I will have to remove a 1-1/2" iron union from the MD 1-1/2" copper suction line ( connection is pipe-thread ). The skimmer suction line will not be a problem, as I will be isolating ( plugging ) the old leaking copper line at the skimmer well, and replacing it with a 2" PVC line, running directly from the well to the pump-house.
The process of removing the MD union gives me the heebie-jeebies, as I am afraid I will be unable to back-up the hex-flange on the copper pipe sufficiently, to avoid twisting the pipe and ruining it. There is only about 6" of pipe protruding from the concrete slab. If I simply cut the copper pipe off at the threaded flange, I will have to then join the bare pipe with a 1-1/2" or 2" PVC fitting with Blue-Glue or other suitable cement. I am afraid that the normal tolerances of the elements in question will not allow for a satisfactory joining of the parts.
All experiences & suggestions will be appreciated.