The Evolution of My Hot Water System - Part 3

If you missed why I'm this involved with a water heater, be sure to check out Part 1<link>

In my continuing drama of hot water, I've finally gotten to actually trying to recirculate the water inside the water heater. This is important because people want to understand why I chose to only recirculate the water in the heater itself instead of throughout the house. The biggest single reason is the cost of electricity, especially in my area with 'demand billing'. If you circulate the hot water throughout the house, it provides instant hot water at the sinks and is really nice. You would only wait a second or so to have hot water to brush your teeth, fill a pot, or jump into the shower. No more waiting forever while that low-flow faucet eventually allows water from the garage all the way into the back bathroom so you can step in without shivering. 

But (there's always a 'but'), you've also extended the capacity of your water heater by the size and length of your plumbing. That means more water to heat. Plus (there's usually a 'plus' as well), you've increased the heat loss even more. Those uninsulated pipes inside the wall radiate the heat you paid for in the water heater, and the cooler water coming back into the water heater trips those heating elements we discussed in the last posting. Up goes your power bill to match. 

It becomes obvious what that would do to my power bill pretty quickly. 

I've thought of a solution to the hot water wait time, though. I'll put a controlled valve at the far end of the hot water line, and when we need hot water in a hurry for a shower or something, just push a button, and the hot water will be allowed to flow full speed until it reaches the valve, and then it will shut off automatically. That way I would only have to wait a few seconds to get hot water at the sink. But (another one of those words), "You're wasting water," you say. Yes, it's dumping water somewhere instead of into my septic tank, and water is a precious commodity in the desert. So, the plan is to dump that cool-to-tepid water into my drip watering system to water the plants.

Total win-win!! I get hot water in a hurry without dumping the cool water into my septic system. It isn't wasted because it goes into my watering system for the plants in the yard, helping to grow lemons and limes for margaritas. This is a project for the future though, because it is too darn hot here to experiment with hot water. 

Now that it's clear why I want to circulate the water inside the water heater to increase the volume of actual hot water and avoid demand billing at the same time; let's discuss how I did it. First, I got one of these:

These pumps are designed to take the heat and run continuously. Look for the best price, but don't sacrifice quality. This thing will be the heart of the destratification system for years and years. There's a caveat to their operation though; the pump spindle has to be horizontal, so it shouldn't be used to move water horizontally. That fits my purposes just fine. I want to take the water from the bottom to the top so it will set off the helper heating element if needed. That also creates a small problem; taking cool water to the top makes cool water immediately available to the faucets inside the house. So, if you use the hot water a minute or so after starting the pump, you might get cold water instead. Interesting side effect for a system that is supposed to help with hot water. It's an easy problem to overcome, though; just don't do that.

All I needed to do was plumb the new pump in, rig up a way of controlling it, and put it into service to gain some experience with this new capability. I trotted off to home depot to grab some fittings and hook this thing in. That's how I learned about SharkBite fittings. 

Typical SharkBite Coupler

These things look like the perfect solution for me because I hate sweating fittings in a confined space. You're there with a torch that can burn a painful spot on a hand or arm in a tenth of a second and start a fire on wallboard if you don't pay close attention, and if you don't have months of experience doing it, leave a leak that you have to come back and fix AFTER you have already gotten everything wet testing it. I hate sweat fittings!! They ain't cheap though; I grabbed what I thought I needed except for one type that Home Depot didn't carry and paid a couple of hundred dollars for them and went to ACE Hardware for the one I needed. This time ACE Hardware didn't carry it either, so Amazon to the rescue ... again. Don't you just love overnight delivery? 

Three days later (so much for overnight delivery), I got the part, and it was time to do this. After I shut off the water and started cutting pipe to put the new fittings in, I discovered SharkBite fittings suck! Here's the first problem; I bought the fitting and the pipe at the same store, and the pipe wouldn't fit into the fitting. These fittings work by compressing a washer against the outside of the pipe when you shove the pipe in; what happens when you can't shove the pipe in? Here I had that expensive copper pipe and even more expensive fittings that didn't work together. I tried using emery cloth to reduce the size of the copper pipe so it would fit into the fitting, and that actually worked, but it was hard to shove the pipe in. I could do it, but it was a painful process. I actually hooked a couple of them up to see how they worked, plugged the open end, and turned the water on to see what happened. 

They held water with no leaks; however, I found another reason to hate SharkBite fittings; they have no mechanical strength. You can wiggle the pipe a small amount and even turn it in a complete circle. I wasn't too happy with the idea of putting in a rotating sprinkler hooked to my water heater, but what the heck could I do? I tried a sweat fitting to see how that went and wasn't at all comfortable standing on a ladder with the above-described torch in my hand trying to get the temperature right to flow that crappy lead free solder over flux that was melting and dripping resin. I was seriously thinking about calling a plumber to finish the job.

I had the water heater set up to work with a plugged line on it, so I turned the heater on and just left it while I thought about how to proceed. A VERY expensive solution came to mind: I could get or rent a ProPress tool. Those things, for copper pipe, cost a lot. The two major manufacturers, Ridgid and Milwaukee, have prices in the thousands of dollars for a basic tool and set of dies. That was just too much money; renting seemed a reasonable idea, so I started calling around. The rental seemed to be around U$50 a day, and I would need a couple of days to be sure I got it finished, but the tools were out, and I'd have to wait to get my turn. Screw that crap! I started looking on ebay and other places for other options. 

Net, I just bit the bullet and bought one of these:

It cost a little over U$600 which begs the question, why spend that much money when a plumber would probably charge less and do a better job? Well, a plumber doing a better job is a crapshoot. Over the years I've experienced both good and bad plumbers. A constant seems to be that they always make the job more complex than necessary; they also suggest things that I just don't want, like whole-house recirculation. All I needed was a motor mounted between the top and bottom of the water heater, not a Taj Ma House replumb. Plus, every plumber I've dealt with is gone in the next two years or so; those people seem to move around a lot. Another reason is that this isn't the only plumbing job I have in mind; there will be others, and did I mention I hate sweat fittings?

And there is the comforting knowledge that I have the independence to do any darn thing I want with the plumbing now and not have to worry about setting my house on fire with a torch next to a wall. My neighbors will love me when they have a plumbing project to do because I have no problem loaning out a tool to help someone. A man that likes DIY can never have enough tools. Here's what the fittings look like both crimped and not crimped:

They have both mechanical strength and seal nicely. This will do just fine. This is what a SharkBite fitting looks like when you have to remove it. 

I had to sand the pipe with emery cloth to get it to fit into the fitting at all, then the struggle to get it to fit deep enough, and then it wouldn't come apart at all when I tried to remove it. So, out came the grinder and a cutting disc. I chopped it to pieces to get the darn thing out. I learned that you can actually remove them with a crescent wrench set to the pipe size and hammer later. People can try them if they want, but I won't waste my money. The ones that I hadn't used already went back to Home Depot.

While all this went on, I kept thinking, "I really should replace the helper element because that is the original, and it may fail." So on one of my many trips to Home Depot, I picked up a new heating element.

Did you notice this element is 1000 watts higher than the one it replaced? That was not a mistake. My thinking is that the more power I pour into heating the water, the faster it will heat. That doesn't decrease the power used; physics prevents saving anything that way. Instead, it limits the time the element will be on. Demand billing is based on time and if I keep the usage below 15 minutes for high current devices like this, it won't show up on the bill. Careful reading of the rules is paramount to keeping my money out of the power company's hands. I'll discuss this more fully in the last part of this project (coming soon).

So, armed with a tool that worked, fittings that actually fit over the pipe, and enough daylight to finish the job, I installed the pump between the heater outlet and drain at the bottom. I tentatively turned the water on a little and let it build pressure, which took some time because the entire water heater was empty ... again. There were no leaks; I had crimped all the fittings, and nothing seemed to be missing, so I plugged in the motor and it actually worked!! I could feel the cooler water from the bottom moving to the top and watched the temperature rise in the heater.

I shut the motor off, grabbed my pile of pipe insulation, and insulated every pipe in sight except the motor itself. The water heater itself is already well insulated and didn't need any more. Then I wired the temperature sensors for the top and bottom right to the copper pipe as close to the tank as I could get them. Some heat-conducting grease and silicon tape to hold them in place did that job. I added a couple of 3rd Reality Zigbee outlets to measure power and give me remote control, and I was ready to put this in service and watch what happened.

The solar pump is on the left, the destrat pump is on the right.

The power leads go to a couple of power monitor control switches.

Did I do myself any good, or did I just waste a ton of time, a dozen trips to Home Depot and ACE Hardware, plus another trip to return the leftover fittings?

Results in the last installment for this project.