Hot and Cold Water Tanks Serviced

Over the last couple of days, we have been servicing the Cold Tank and also Activating the Hot Water tank, ready for heating. We wanted to get our Hot Water tank operational, which was empty. So, the first job is to fill it up with clean fresh water and we thought we would get it from our Cold Water tank since it is lovely and clean, soft rain water. But, we discovered that the water in our Cold Water tank has been growing scum. We had originally dropped a couple of chorine tablets but it was clearly not enough concentration to inhibit the biological processes. The main problem was that the water had been static for months, ever since we had filled it up last year before the Summer, and of course, the place got rather warm with all the sunshine pouring in the Skylight. There was enough dirty surfaces inside the tank to provide food and nutrients and perhaps, in hindsight, we didn’t do a very good job of sterilising the tank itself before we put in fresh cold water from our rain water tank, going through our three stage filtration system of 1micron particle filter, activated carbon chemical filter and UV to kill biologicals.
Silly Us! Phew! We learnt a lesson about getting things clean first!
So we spent the day emptying the dirty water out of the tank and down into our sceptic tank via a waste pipe we had available upstairs. We sucked the water out using a submerged pump and then vacuumed the rest of the water at the bottom of the tank, as much of the scummy rubbish as possible. We then half filled the tank up using more rain water, going through our filtration system of course but this time, we brought some bleach liquid and poured the entire bottle in, squirting directly onto all the walls and then scrubbed the surfaces with a large brush. We even got our battery powered pressure washer to blast the parts of the walls that we could not reach with the brush. We also wanted to flush out our water pipes running around our house, especially those pipes feeding the cistern and basin in our Cloakroom. So, we found a coil of 28mm plumbing pipe we had left-over and connected one end to the end of the main pipe in the Kitchen, run the plumbing pipe out into the Hallway, then out the Front door and finally out to our Loke, to discharge the “Dirty” water. We powered up our installed cold water pump in the Utility Room and blasted the bleachy water through our pipe, including flushing our toilet several times and running the basin water as well. Next, we filled the tank back up, this time, right to the top and rinsed all the surfaces down including the feed pipe, and proceeded to empty the whole lot again, to flush out the pipework and this time, we refilled the tank and dropped in five of the chlorine tablets this time. There is definitely a smell of chlorine now.While that was going on, we decided to fill the Hot Water tank with the domestic mains water instead, knowing that it is clean and chlorinated and even though it would have a tiny amount of calcium carbonate salts in the water, it is just an one-off amount and will not cause any problems with our valves and pumps etc. The size of our Hot Water tank is 270litres so it took a few minutes to fill it up. Just as a comparison, our Cold Water tank upstairs is 500litres, so you can imagine how long that took to fill and empty three times !!

Anyway, the Hot Water tank is now full.
Next, we finished making the electric heating elements. We had to extend the length of the cables because the manufacturer only supplied a metre and we wanted at least 2metres and more, long enough so that the heating element itself can reach down to somewhere near the bottom of the tank so that the heat will rise up, especially with our automatic circulation system where the hot water is continuously sent around the hot pipes and re-enters back into the bottom of the tank. We needed to make sure that the joints are boil and water proof so we got some high temperature sealant to squirted into the heat shrink tubing that is covering the soldered copper wires.
We got ten individual heating elements, eight of them are rated at 50volts DC (so they can run directly from the solar panels and batteries) and two mains 230volts AC (as an additional backup).
The 8 DC elements all come with different power ratings as follows:

• 1 x 500Watts
• 1 x 750Watts
• 6 x 1000Watts

And the 2 AC are as follows:

• 1 x 1000Watts
• 1 x 1500Watts.

Most of the time, the Hot Water will be heated using the DC heating elements, which means that we can gradually turn on more and more elements as there is more and more solar energy being collected and we can fine tune how much power is drawn into the hot tank, anything from 500W, in 250W steps, all the way up to 7250W in total.
So, we lowered all ten elements down into the water in various locations around the tank so that none of the heaters were touching each other and we now have a whole bunch of cables coming out of the tank at the top.

What we would like to see now, is a full blown test of bringing up the temperature of the water, all the way to as near as to boiling point as possible. We want to make sure that the tank itself can handle the heat and that we don’t have any leaks. It is ok at the moment but it is only cold water.