Today I resumed installation of the water tank connections. Had to get a few more hose clamps. I had been thinking a while what to use for inlets and outlets, if I should use pex or push in fittings with standard 12 mm piping etc.
One reason I use food grade hose and hose clamps with poly fittings is weight again. I have motorised ball valves at the inlets and outlets of each tank, they already add up in weight. A lot more brass fittings would considerably add to the weight.
I will use pex for the hot water connections where the normal plastic hoses have a problem with the temperature. Unlike a “normal” caravan I am running a much higher temperature in the hot water pipes. The outlet temperature of the calorifier will be around 70 to 80 degrees which is easy achievable with the solar panels as heat source.
Usually one would run a lower temperature to avoid scalding under the hot water but this is not a problem for us since I use temperature controlled mixers everywhere with hot water circulation pipes. This creates instant hot water at the temperature we want.
Right now I am working on the cold low pressure side, inlets, outlets and breather connections of the water tanks.
Making sure that I have a slight slope down into the tanks in case water builds up in the fill or breather pipes. Since I have valves in the fill lines and when I do fill less than all tanks, some water will be left in the filler lines of the other tanks before the valves. This is not desirable for hygienic reasons. In a moist environment bacteria can breed easier than in a dry environment. For this reason I have a blow through mechanism in all fill lines. I can open all valves and blow through with compressed air (flow regulated) the fill and breather lines. No water, or at least very minimal, will remain in those lines after each fill.
Above image shows a ball valve. They are motorised and only draw current while they open or close and even then very little. I have feedback signals for completely open and completely closed. All inlets and outlets have 20mm inner diameter.
Here is an image from my installation wiki, where I document the location of each component for later reference.
Tomorrow I will do more plumbing work and hopefully by Thursday I have all the tanks and pumps connected. The holding tanks will be done after I return from QLD.
I use the same ball valves for the glycol heating system to open and close heater circuits driven from the diesel heater. Those valves are DN15 not DN20 and are stainless not brass.