Still working on this ice rink volume of the pipes problem. Step one was to do a leak test because, as we had discussed, leakage in these buried-in-concrete pipes would be a major game changer.

So, I hooked up a compressor and found, well, leakage. But it wasn't coming from the pipes, the isolation valves were leaking enough to make this test invalid. So, I decided to disconnect the pipes at the isolation valves and plug them. Of course, they don't fit "normal" test plugs, so I made up steel plates covered with closed-cell neoprene foam sheet to sandwich between the pipe and valve flanges.

The two 2" supply pipes were no problem. The 4" return pipe, however, required bigger wrenches than I have. "Easy." says I, "just go to HF and get their jumbo combination wrenches with the 20% off coupon." So I went and got the wrenches, and also picked up a set of big impact sockets (3/4 inch drive - needed an adapter for that).

The friggin' wrenches don't fit. They are in 1/8" increments, and the two sizes it turns out I need are 1 5/16 and 1 7/16. Totally useless, they are. Near as I can tell, HF doesn't sell those 16th size at all.

Fortunately, the socket set is by 16ths, and I was able to use a 1 5/16 socket on the bolts and an adjustable on the nuts. But sheesh, wouldn't ya think?

I have taken measurements off the fitting and cut a plate to size. In the morning, I'll drill the holes in the plate and cover it with the neoprene, bolt it up and get back to testing.

BTW, I was able to loosen one of the four bolts with my puny Porter-Cable 1/4" 20V impact wrench, and the 1/4 hex to 1/2 square adapter did NOT twist into a pretzel. My 1/2" air impact (bought from enco 20 years ago) made quick work of the others.