The Evolution of My Hot Water System - Part 2

 In part 1 <Link> of this compendium, I described my experiments with creating hot water under power company demand billing and what some of the pitfalls were. In this part I want to discuss my technique of getting ENOUGH hot water on cloudy days. Sure, with the rainfall in the desert, this shouldn't be a problem; after all, the cold water is always over 80F during the summer. I guess I'm spoiled; I like a hot shower, not a lukewarm one. It's really pleasant to soak in a hot tub full of water with a book. Creature comforts are important.

We don't get many cloudy days, but there are enough to get annoying in the cooler weather when clouds take over the sky and solar just doesn't produce enough heat to give me enough hot water. What to do about that annoyance. After all, automating a house should make it more comfortable ... right??

Way back when I first started measuring the temperature of my water heater and recording it, I posted graphs and charts describing my findings. A couple of comments pointed out how my water heater was stratified, and I spent some time thinking about that and experimenting. Yes, the very fact that warm water rises and cold water sinks was causing much of my problem of not quite enough hot water. 

Let's take a look at what goes on inside a water heater, this is a typical electric hot water heater.

I grabbed this directly from a Sears site for illustration.

I'm sure they don't mind because it is free advertising for them.

Water comes in the top through a tube to the bottom, and when it is too cold, one or both of the heating elements turn on. This heats the water, physics works its wonders, and the hot water travels to the top. This, one would think, causes the water to mix and the temperature to equalize inside due to the motion, but it doesn't quite work that way. The top element actually reaches the set temperatue and shuts off, the bottom element eventually gets to its setting and shuts off also. That leaves around half a tank of hot water at the top and the cooler water at the bottom. 

Water is drawn from the top, so you get hot water at first, but as the water heater is drained, new cold water comes in through the input tube to the bottom, setting off the temperature sensor there and turning the bottom element on. That warm water rises and mixes some of the incoming cold with the hot water at the top. Your water heater is actually being cooled by new water and the circulation of the water inside the heater as it works. 

Then, on go the heating elements and up goes the electric bill. That shower after work and before the family notices how bad you stink from working outside all day combined with Peak Demand Billing just cost you an extra $40 on your electric bill. Those heating elements are usually 4500 watts each, and there are two of them for 9000 watts. If they run for an hour to heat up all that water, you just used 10kWh of power. If that happens during peak demand (like we have here), you WILL see that on your bill at the end of the month.

See why I put in a solar water hot-water heater? That left me somewhat less vulnerable to the chiseling, money-hungry bureaucrats at the power company. When I combined that with literally shutting off the heating element on the water heater during peak periods, I could pretty much thumb my nose at them because the bottom element is actually a radiator hooked to a solar panel on the roof that heats water and a pump circulates it in a closed loop that only transfers heat without stirring up the water inside the heater. Mine is sort of constructed like this:

This is called indirect solar water heating. The bottom heating element has been replaced with a radiator. A pump in the plumbing pushes antifreeze-treated water through the accumulator on my roof so the heating is held to a closed loop. The top element is still there and is called a helper element. It is a combination of both mains-powered electrical heating and indirect solar. My expense is only for the 45 watt circulation pump when the hot Arizona sun is doing its 'thing' and some minor 'top up' actions from the helper element at the top.

Now back to the stratification problem. The obvious (to me) solution is another pump in the plumbing. I have a nice hole in the top of the tank that I can use and another at the bottom as well; I should be able to pump water from one to the other and stir things up so the entire 80 gallons of water are at the same temperature. That will give me more hot water than I need and a long hot shower for the wife (happy wife happy life). All I needed to do was run a pipe from the bottom, through a pump, and into the top. That would solve all my problems. That's exactly what I decided to do.

First I gathered some parts and pieces to do the job: pipe, fittings, pump, and cleared out the garage where the heater was. I dragged in a water hose and hooked it to the drain line, shut off the water, and opened the drain faucet. The idea was to start draining it with pressure applied to force out any material that might have settled to the bottom 

Nothing happened. No water came out of the hose. I waited, still nothing. Felt the hose, and there was a little heat near the faucet, but it didn't go down the hose. What the heck? I went outside, to see if any air was being forced out of the hose, again nothing. I stood there scratchng my head and wondering what was going on. In a bit of desperation, I decided to pull the faucet off the bottom of the heater to see if it was plugged up. 

After turning off the water, I disconnected the hose, and it had some calcium chunks in it surrounded by a milky calcium-laden fluid. Yep, it was plugged. Now how do I drain a full tank of hot water with the faucet removed? And what about the possibility that the bottom of the tank was plugged with this milky stuff? I needed a way to let air into the tank so it would drain as rapidly as possible; how was I ... Oh wait, I also needed to replace the sacrificial anode at the top of the tank!! If I took that out it would let air in the top, and I could mess with the faucet to try and clear it. That's the ticket; pull the anode.

For those of you that have never pulled the sacrificial anode out of a water heater, here's some sage advice from someone that has done it themselves. Call a plumber. 

I didn't do that; instead, I tried a crescent wrench, then a bigger crescent wrench, then a piece of pipe on the handle of the wrench, then a longer piece of pipe. Nothing would budge that stupid thing. What exactly was the manufacturer's goal in putting that fitting in so tight? Did they locktite it in place to show us common folk how inadequate homeowners are at maintenance? Was it a plot to guarantee a plumber's trip to the house? Do plumbing manufacturers conspire with plumbing unions to guarantee work? Could it have been cousin Bubba, your 300-pound relative with a breaking bar, chuckling about how frustrating it would be for someone 10 years later trying to get it out? I suspect it was the setting on an automatic wrench on an assembly line in some factory somewhere. Some lazy inspector or quality control 'specialist' is not doing their job, and we get to pay for it in time, money, and frustration.

I didn't have a socket that would fit it; those things take a 1 1/16 socket. Who has one of those in their toolbox? Amazon to the rescue: I ordered a kit containing both the anode and the correct socket, then played the waiting game. My project ground to a halt, the garage stayed a disaster zone, and I was left entirely at the mercy of the delivery driver. For many hours, my immediate future, and the progress of my project were completely out of my hands. "Please mighty King Amazon, have mercy on your subject."

My whining must have worked because they arrived the next day, and I took the socket and my brand-new 1100 ft/lb impact wrench, and with a little wrangling around, I got the darn thing to unscrew. Think about this for a moment; I had to use an impact wrench that I have used to take the lug nuts off a 20,000 pound backhoe for a neighbor. I've intentionally broken the heads off rusted 3/4 inch bolts so I could drill out the hole it was in with that thing. I have to be careful to make sure the wrench doesn't turn me instead of the bolt. That kind of power should be reserved for an adventure with the bucket of an excavator, not a silly plumbing fitting on a residential water heater. Note to manufacturers: never underestimate the homeowner; we will overcome.

When I pulled it out:

Yes, maybe I should have changed it sooner...

The white stuff on it is calcim, not magnesium like it was supposed to be. Let this be a lesson to you readers: check that anode. However, in my defense, I couldn't get the darn thing out in the past. Yes, I tried several times, and this was the one time I actually succeeded. The power of the big impact wrench finally overcame the resolve of the rod being evicted from its home. Now I had air going into the water heater to let the water out. 

I placed a bucket under the drain faucet at the bottom of the heater and turned the water on. Nothing. This time there wasn't even a drip. Standing back and looking at it, I was a bit overwhelmed. So I tried a coat hanger as something to punch the calcium around until I could get some water flowing to rinse this thing. The coat hanger wire hit a hard stop in the faucet and wouldn't budge at all. Fine, I have pipe wrenches; it was time for the last resort ... pull the darn faucet out. 

I grabbed a good-sized pipe wrench, moved the bucket out of the way, and throwing caution to the wind, unscrewed the stupid faucet. Since there was no pressure other than the weight of the water, I actually got a slow flow of milky white goo. A little prodding with the coat hanger loosened it, and it actually started to drain on the floor of the garage. I just stood there and celebrated my limited success. Sure, I had a mess, but it was actually draining after hours of messing around with it. 

Turning my attention to the faucet, it was obvious why the darn thing defied me:

This is a view of the whole thing. Notice how they put on one that isn't like our normal hose bib out in the yard. This thing is long and looks like it is special in some fashion. Next is a view straight down the hose end of the faucet. Notice the typical valve that anyone who has worked with outdoor faucets is very familiar with. 

Let's look down the other end.

See that teeny, tiny hole down there? That's all that's provided to drain the darn water heater, that tiny little hole. That's what the chunks of calcium hit and wouldn't let water pass. That poor excuse for a drain is obviously designed to impede maintenance of the water heater instead of allowing it. Solar water heaters are expensive devices that should make life easier and cheaper. We pay big bucks to save money, and they put a faucet on for cleaning out the tank that limits flow to roughly what Grandma can suck through a martini straw. I decided right then that faucet was not going back into my water heater. 

Instead, I fashioned a new drain valve out of a short length of pipe, a brass fitting, and a nice ball valve that wouldn't restrict the water. Something like this:

These things allow full flow through the pipe and don't have a tiny little hole to plug things up. After I got that put together, I just plugged in the new sacrificial anode into the top using a lot of teflon tape coated with pipe dope and tightened it down with a regular short crescent wrench. I was not going to tighten that new rod in like the old one was; I wanted to be able to change it with an 8" crescent next time. I used one of those 'flexible' anode rods because I didn't want to inadvertantly screw up the radiator at the bottom of the tank. If I shoved one of the flexible rods into the tank, it wouldn't gouge a dent into the radiator. 

Then by attaching a water hose leading out to the yard, I was able to finally flush the heater of all the crap that had accumulated over the years. I filled the water heater, left the water pressure on and opened the valve. 

I watched the water come out the end of the hose, and the chalky residue flushed out pretty quickly while I watched for that demon of water heater destruction ... RUST. Fortunately, there wasn't any rust flushed out. Apparently, with the exception of the useless and damaging drain faucet, I had a good water heater. It hadn't rusted in spite of my lack of maintenance. 

I had just spent two entire days and hadn't made any progress at all toward my actual goal of putting in a recirculating pump to counter the stratification of the water heater. Two trips to Home Depot and a lot of stomping around the garage in frustration, and I was still just starting the actual process. Speaking of which, what's up with Home Depot? Have any of us ever found all the pieces we need? There is the advantage of getting more fittings than we need because they are great about returns, but having to go to ACE Hardware for a fitting when Home Depot is out is a pain. I do like the folks at both stores though, especially the ones at the return desk. 

BUT, it was time to get the hot water back on and clean up some of the mess I had with calcium all over the wet garage floor. The wife-comfort aspect of home automation is important. She should look forward to the new improvements in lifestyle, not cringe at her water heater being down for days while we stumble around making stupid mistakes and overcoming bad design decisions from some manufacturer or assembly line worker. Especially the part about waiting for an Amazon order to arrive.

So, I double-checked for leaks, dragged the hose out in the yard, and turned the heater back on for the night; the next step could wait until tomorrow. 

See you in part 3.