Quick change water pump

When I first moved here, there was a large steel water tank on a concrete slab. A nice start for a good water system, but with only gravity feed, it has to be 3/4 full to get usable water pressure. I added the pump, pressure tank, filter, batteries and solar panels. The ends of the 2x6s sticking out from under the tank make a nice mounting place, even if the layout is strange.


Everything worked fine the first summer, but in the winter there wasn’t enough power for the 3 GPM pump. Rain in the winter means less sun and less need for water. Summer brings more need of water and more sun to power it. Switching pumps each season involved a lot of cutting pipes and gluing them back together. Eventually I came up with the design shown below, which lets me quickly swap pumps in a matter of minutes.


First we need some power. The two blue panels on the left are poly-crystaline Solarex MSX-64, fast approaching 20 years old. Unfortunately the tree line moved, so these get a little too much shade now. The six 75 Watt single crystal panels on a nearby shed help out. They were made by BP (yes, that BP) about ten years ago.

A place to store power for rainy days. Four Trojan T-105 6 Volt batteries, just a few years old now. 2 in series for 12 Volts, and 2 sets of those in parallel doubles the amp*hours capacity. Overkill? Certainly! Nice for the winter when sunny days can be far between. And with 5,000 gallons of water at hand, having the power to move it seems prudent during fire season.


The thin gray box at the bottom center of the photo is the charge controller. Xantrex used to be called Trace Engineering and their old stuff still works great after many years. I wouldn’t buy any such devices without a low-voltage cut-off feature, which saves much heartache by protecting batteries. These batteries are fairly heavy, so they have a small poured slab of their own. The box around them got a little bent when a tree fell on it in a storm. Unless outdoor spaces like this are really tight, don’t be surprised to find evidence of little furry ones living in them.


This is the quick change setup. Two pipe fittings, I think they are a kind of “union”, and two 90 degree turns to get the pump’s in and out pipes parallel. The black bands
around the gray pipes are like a gasket. There’s a close up of these below.


Teflon tape for the threads, to prevent leaks. Push the gaskets and the the gray pipe into the union until snug, then screw on the cap.


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