Friday, 9 October 2015

Installation of pressure pump for rain water tank

I've had the pump - a Salmson "Jetson Portable" - for nearly a year, but had no reason to install it until today, when the municipal water pressure in my part of Grahamstown failed as more Makana infrastructure collapsed.


I've subsequently seen at least three other versions of this type of pump by different manufacturers for sale in various hardware/engineering emporiums, varying from R1400 to R2000, so clearly it's a thing. And quite a fast moving thing, as the piles of stock rise and fall quite regularly.


Interesting that it's French, and not Chinese... a recently purchased wheelbarrow is also French. Maybe a Wallmart type phenomenon now they're established in South Africa?

My rainwater tanks have been up in expectation of this for more than a year, and are full of clean water thanks to the first flush diverter/filter attached to the gutter down pipes on my roof. At that time the house plumbing reticulation was extended to the tank stand, an external power socket was installed, and an underground sleeve installed to route a power cord onto the pump stand. Everything, in short, except actually installing and connecting up the pump itself.


Stage 0 (above) - part of the preliminary work, done late last year - a one way valve between the house plumbing (off to the left) and municipal supply (off to the right). I don't want to donate my rainwater to the neighbours or the municipality when my pump starts up. Alternatively, I can close the stopcock and go "off grid" as regards water. Which wouldn't impact my account, as the municipality actually reads meters once or twice a year, if that...

It's nice living where there's little or no freezing weather, which means all the plumbing is on the outside walls. Easy to modify and extend, but also easy to steal if it's copper/brass.

You can see the remnants of copper water pipe theft from a few years back, when the miniature burglar busy ripping pipe off my walls was disturbed in the act. In his hasty retreat hopping over the fence into the neighbours garden he dropped a pair of rubber kitchen gloves (to disguise finger prints?) and the giant pliers he was using to break up the pipe into short segments to load up in his plastic bag. He had the decency to leave a bit of the pipe leading from the municipal stopcock sticking out of the ground and crimping it to stop the water spraying all over the place. Or maybe that was just in order not to be given away by a telltale fountain. Fortunately this was discovered about 11h30 on a Saturday morning, which gave me a chance to rush off and buy some polycop and fittings in order to effect my own plumbing repairs. I've now laid in a stock of plumbing essentials for future emergencies - and for homegrown plumbing extensions around the garden and outside room.

The patch of black spray paint on the wall was to disguise part of the original repair in order that it didn't appear too "coppery/brassy". Now most of the remaining copper pipe work and valves is hidden behind trellises, and the subsequent security upgrades round our perimeter seem to have driven wannabe opportunists to try their luck elsewhere. No doubt they'll be back when the neighbours catch up in the arms race and I again become an easier target.


Stage 1 - done early this morning under supervision of Antigone - bolting the pump to the tank stand so it doesn't develop legs and wander off. The trickiest bit was getting holes drilled into the over engineered concrete tank stand with my under powered drill. Thanks again to Andy Bradfield, who did in 15 minutes what I failed to do in a frustrating hour. The electrical conduit and polycop pipe were installed ages ago, and weren't ideally positioned as the pump has now been located on the stand so that it's not too visible from the street. The power cord was pulled through the sleeve and a 15 Amp plug installed. A quick power on/off test got the pump spinning. All OK so far.



Stage 2 - connect the rainwater tanks to the pump with 25mm PVC pipe. It's not yet a neat installation, as the manual talks about a two metre straight run of pipe leading to the pump intake to avoid cavitation problems. I'll see later if I can tie it to the stand somehow without putting kinks into it..

It wasn't necessary to use the blowtorch to "heat shrink" the PVC pipe onto the elbows and connectors, but I'm getting creaky and like to avoid unnecessary to-ing and fro-ing to fetch stuff from the other side of the house.

Interestingly, when the valve between the two tanks was turned on, water went straight through the powered off pump and poured out of the unconnected outlet. I hadn't expected this. When powered on, water shot from the outlet at reasonable pressure.

Even though there is a drainage plug and a priming plug on the pump body, they haven't yet had to be used.


Stage 3 - connect to the house plumbing, using polycop pipe and mainly PVC fittings. These fittings are wonderful - they don't leak, even if imperfectly aligned and tightened, they are reasonably priced, and are eminently unstealworthy having no scrap metal value.

The brass stop valve leads to the house, and the PVC valve to a vertical pipe so that if necessary in future I can fill my tanks with municipal water, or pump water from the tank straight back into the tank - useful if you're distilling moonshine and want to modify it slightly to run coldish water through a condenser. At the moment the vertical segment is quite short and terminates in a stop end while I work out how to get it neatly into the top of the tank without introducing mosquitoes as well.

At this point, powering on the pump showed that it worked pretty much as expected. It goes into "alarm" mode if the wall switch/motor switch sequence is done incorrectly, but can be reset either by power cycling on the wall, or pressing the reset button.

One issue highlighted by this is a tap in the bathroom with a slow drip, which seemed to be causing a slow pressure drop, and making the pump kick in more often than expected to maintain pressure, about twenty seconds pumping every minute. But further thinking about this made me look at what happened in Stage 2 - there's no internal one way valve in this particular pump, so it quite quickly loses pressure back into the rainwater tank. Other versions seem to have the valve built in,

A hurried trip back to Albany & Bathurst Engineering before they closed for the weekend at 15h00 and I got the missing ingredient.


A 1" one way valve, plus the requisite PVC fittings to install it inline into the 25mm PVC pipe from the tank..


Stage 4 - One way valve installed the correct way between rainwater tanks and pressure pump. Now the pump maintains pressure in the house plumbing for nuch longer periods. I took the opportunity to add more plumbers tape to the fittings attached directly to the pump, as there were slight leaks.

It also means I can leave the pump switched on even when the municipal water is also switched on and feeding into the house plumbing. Without the one way valve, I'd fill the tank with municipal water even if  I didn't want to, and be unable to control overflowing. Now the only water going into the tank is from rain.

At the moment I've got the municipal water turned off, and things are working fine - the slight anomaly is that when a tap is turned on in the house, there is a low pressure start, followed after a few seconds by high pressure. I'll run like this for a couple of days and see what else crops up.

Still to do - find or make a cover for the pump to keep the exposed bits clean, dry, and disguised. A suitably sized PVC box or bucket with holes/slots in the relevant areas should do the trick.

Another thing to establish over the weekend is how to adjust the pressure - it seems to be set to 3 Bars by default, and I need to see if increasing it a bit might help with the coverage of my garden irrigation. On the other hand, I don't want to burst any pipes or geysers!

So, a reasonable conclusion to the day. I'm now actually making use of the water I've been collecting so diligently...

I suppose the downside of all this is no fluoride, but at this stage of my life most of my teeth are false, anyway. Just as well all our kids are grown up.

Update 2015/10/14:

Pressure with municipal mains connected is 10 Bars, which is the max reading on the gauge. One possible issue is that my cold water line is based on 13mm pipe and will need more pressure than if it was 20mm.

Update 2016/04/10:

I drained the two tanks last week, after my daughter noticed mosquito larva swimming around in the water she wanted to use for making ginger beer to sell in the newly established "Grahamstown Bakery". She reverted to getting brewing water from the spring on the Port Alfred road below mountain drive while I figure out how to mosquito proof the tanks.

Hmmm....

Update 2016/04/28:


A modification to allow water to be recirculated via the pressure pump that would allow it to be diverted through valves into something like the condenser of a still. You'll need to fit connections to the still onto the stubs.

Alternatively, it lets municipal water into the tank. There's no overflow detection.

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