Monday, October 8, 2007

Don't you have a MAPP?

After doing a bit of research into tips on soldering big brass joints (1.25") to copper, I was feeling pretty confident to have another go at those tricky fittings that stumped us the night before. The best tip that I received was to switch from propane to MAPP gas, which burns hotter. Other than that, it's all "common soldering technique," which includes cleaning your fittings exceptionally well and adding enough (but not too much) tinning flux. This time, it worked.

Not only did it work, but this mystery of "capillary action" where the solder wicks itself into the fitting was revealed. "Whoa, did you see that?" It really works...the molten solder zipped right into the fitting almost as quickly as it pooled up on the pipe. Then it all made sense - if the solder pooled, I'd back off on the solder and add some more heat deep down on the fitting until the pool of soldered flowed inside, then I'd add a little more. Neat!

So, we soldered - wait, I'm going to start calling it what the pros do now - we sweated all the appropriate fittings onto the pumps manifold and then aligned and mounted them to our wood panels using split ring hangers on threaded rods. After sweating this assembly to the rest of the PMP, we were lookin' good. We were short one fitting (as usual) and almost out of solder, so we called it a night.

Saturday morning, I couldn't even wait through breakfast to get back to the copper. Scored the fitting and some more solder and took my coffee to the basement and started prepping. The night before, I realized that we had sweated 3/4" copper to 1/2" PEX atop each manifold, and we should've sweated 3/4" copper to 3/4" PEX. So, we had four incorrect fittings on the wall that needed to be removed. I got on that and had little trouble. Erika grabbed 'em with pliers as soon as the solder melted, and I cleaned the hot pipes off with a dry rag.

We sweated the correct fittings on 1-2-3-4. Again, the capillary action amazed me; with the correct amount of heat, I was watching the solder run UP the pipe and into the bottom of the fitting. Gravity be damned! Very cool.

We ran into a little trouble sizing the length of copper pipe required to run from the heat exchanger to the elbow that lines it all up with the return manifold that we were about to mount, but that didn't hold us up too long. We decided to go the pro way for the last round of sweating - we cleaned and fluxed several fittings, fit them together, mounted the manifold, and soldered everything in place, five or six fittings, right down the line. We stepped back and admired our copper assemblies.

Next step was to make the final connections to and finish our PEX manifolds. We're comfortable enough working with PEX now that we did away with the measuring and just sized it up and cut on the fly. We ran out of crimp rings but decided to cut and install anyway, so we could have that all ready for the next morning after we'd hit the hardware store again. We had little trouble finishing this up.

It was still early in the day, so we started splicing in the ball valves. Remember the orange PEX tubing circuits? Well, as it turned out, we were supposed to have installed a ball valve at the start and end of each one. A ball valve is basically and on/off lever. On, water flows through. Off, it doesn't. It's good to have these on the circuits for balance and isolation reasons. Good for diagnostics, maintenance, and fine-tuning.

It wasn't too hard - snip snip, crimp crimp. We took care of the ones in the basement (10 of them) and left the upstairs one for the next day.

I grabbed the machete and went off into the woods to continue our path up into the back field.

- John

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