Having Fun With Some DIY Plumbing

[marvoni]

We're in the middle of a drought with 'day zero' estimated around May next year so I've decided to go off grid, or partially off grid in an effort to ensure I still have water at home.

I decided to use my borehole water for most of the house and just use council water for human consumption such as drinking and cooking. This has meant I've had to split the plumbing into two circuits, borehole water now supplies the 5 bathrooms and council water supplies just the cold water on the kitchen sink, the coffee machine and the soda machine which are both permanently plumbed in. There's also an option to revert back to council water for the entire house as well.

It's meant some serious DIY plumbing, although probably not plumbing as you know it, over the last month or two.

 

[marvoni]

Thanks Ric. TBH the plumbing changes I'm making aren't motivated around reducing environmental footprints, it's merely about having water at home if/when it runs out or they start turning off water to whole suburbs for periods of time to reduce consumption.

I looked at several possibilities such as rainwater storage, gray water treatment and storage etc but where I am the rain is very seasonal and the storage volume requirements would be prohibitive on both cost and logistics side for such a system. Gray water treatment on a small scale would be viable but on a larger scale in our climate there's health implications associated with standing contaminated water. The yield to cost ration of such a system would be small

First step was to reduce consumption which was no easy feat with two teenagers in the house. We're down to consuming around 8-10 kilolitres per month (from 20 kilolitres initially) which was achieved by relatively simple measures such as placing a brick in each toilet cistern, installing low flow shower heads and generally educating the family on not wasting amongst other things. It also helped that the council pressure was reduced from around 11-12 Bar static down to 3-4 Bar at present because it was a constant battle with dripping taps and ball float valves overfilling toilets and overflowing.

 

[marvoni]

We've had a borehole for around 15 years which I installed myself for garden irrigation. Touch wood it's always delivered water, even in our dry season, at a rate of around 22-25 litres per minute. My cheapest and easiest option was to extend the existing borehole system to supply the house also. I finish my drawing so you can see the system in its entirety;

 

[marvoni]

Getting back to the back-flow issue I'm comfortable that the risk is low and can be managed. When the system is configured so the borehole water is supplying the bathrooms, the hand valve, labeled 'Valve 1' on the drawing above, will be manually closed. I'm happy that the chances of a hand valve on a clean council water supply allowing leakage back through it are minimal. The check valve situated upstream next to it is double protection against it. The only way the risk is increased is if the various valves are wrongly set or opened and closed in the wrong order which is unlikely as I'll be the only person operating them but I'll make up an instruction card and hang it on the manifold as well.

 

[marvoni]

Managed to spend a few hours on the water installation today, completed the PRV, filter and pressure tank install and got the pipe to the borehole panel buried and connected. Pressured the system up and fingers crossed no leaks.....yet....

 

[ShaunCorbs]

Just a tip pressure regulators don't like to be on there side or downwards facing so needs to be turned back to the wall

 

[marvoni]

Thanks Shaun, I'll turn it around.

 

[Chuck]

Have you thought through the implications of putting the pump (and other electrical gear) in what looks like a rather well-sealed box. How's the heat that the pump motor will need to need to dissipate going to get out?

 

[marvoni]

That panel was already existing, it's a year or more old, it's just the trenching I did yesterday and a new 25mm pipe that I installed to it.
You can't see in the photo but the panel has a 100mm circular cut-out for the air flow on the left hand side where the back of the pump is and there's several.....from memory I think 8 or 10 x 25mm vent holes in the bottom of the panel.

I checked temperatures during the 1 hour irrigation cycle when I built the panel and there was no overheating issues as long as the head pressure was above 2 Bar.

There was one irrigation station back then that was running at very low pressure and the pump got close to its temperature limits when that station was active but I re-jetted the sprinklers to increase the water pressure and increased the run time of that station which solved the problem.

 

[marvoni]

Well my system has been up and running since early Jan and our council water consumption is going to be just under 1 kilolitre per month which is great.

I have one slight unforseen issue....more of an annoyance really. The borehole water has some air in it which makes the showers 'spit' every 30 seconds or so when you use them. You can also hear spitting noises in the toilet cisterns as they refill.

I should have really preempted this issue because the irrigation system that was previously running on the borehole also used to make periodic spitting noises but it was never an issue we worried about when it was just irrigation.

The showers however go momentarily hotter or colder when the spitting occurs so it's something I'd like to remedy if it's not too involved or expensive.

So what I need is a cunning and inventive way to remove air from a sealed and pressurised water system, a way that's ridiculously cheap, can be done using the very basic plumbing components we have available off the shelf in far flung Africa and can be installed by a plumbing muppet with zero plumbing tools or experience.

Yeah....not asking for much I know but God loves a tryer....so they say.

 

[ShaunCorbs]

two options but whats your pressure of the pumps / coming out the taps at and flow rate?

 

[marvoni]

The pressure of the borehole water system is regulated to around 3 bar with a PRV before it reaches the house. Flow rate varies, I'd guess when someone is using a shower or filling a sink it might be 15 l/min, if a toilet is flushed it might be 10l/min etc. I'd gusee max flow rate would be 25-30l/min but only for short periods.

 

[marvoni]

The pressure of the borehole water system is regulated to around 3 bar with a PRV before it reaches the house. Flow rate varies, I'd guess when someone is using a shower or filling a sink it might be 15 l/min, if a toilet is flushed it might be 10l/min etc. I'd guess max flow rate would be 25-30l/min but only for short periods.

 

[ShaunCorbs]

how are you at fab work

you could try one of these and a piece of 50mm tube as a res / somewhere for the air to rise

27735 - Flexvent - Flexvent automatic air vents - Venting Range and Air/Dirt Separators - System Components for Heating, Cooling and Potable Water Installations - Products

or you would have to email these to check the flow rates are ok

Spirotech | maximising performance

 

[marvoni]

Thanks for the ideas, I do have a small fabrication workshop where we manufacture stainless steel enclosures so I can make something moderately complex if necessary. I'm not sure about fine machining of valve seats etc, my lathe is pretty large so that might be a problem.

I might be able to manufacture an electrical version with a solenoid valve operated by a small electrical float switch rather than a mechanical version.

 

[ShaunCorbs]

think you will be hard to make an auto air vent, but you could make a stainless steel tube with a 3/4 tapping one end and the other end to suite your system

 

[marvoni]

Do you think something like this might work?

 

[ShaunCorbs]

yes but would go with 3/4 connections and some baffles internally

 

[marvoni]

3/4" connections are no problem, I've got tank adaptors in stock even up to 4".

How would you suggest might be an effective internal baffle arrangement?

 

[marvoni]

Would it be reasonable to assume that any air travelling inside the water pipe would be mostly at the top above the water or do you think it would be well mixed in with the water?

 

[marvoni]

Something like this maybe?

 

[ShaunCorbs]

depends how much air if theres a bit that should work and great on the baffles

need to make the cylinder as big as possible

 

[ShaunCorbs]

its one of them the bigger it is and dia the better it will work and easier to make

 

[marvoni]

Okay, I had a scratch around the workshop and the largest size pipe I have is 67mm OD in classI copper and I also have a couple of copper end caps which is handy. I'm trying to avoid purchasing pipe because it means I'd have to buy 6 meters which probably won't be cheap so I'm keen to give it a go with this off-cut I have.

The size of the water pipe going to the house is 22mm copper meaning the tube I have is approx 10x larger in area so, unless I'm missing something obvious, the velocity of the water passing through the separator will be 1/10th of what it is in the 22mm pipe. Hopefully this will be sufficient slowing of the water velocity, along with a couple of internal baffles, for the air to separate....

 

[ShaunCorbs]

Worth a go / try, only thing you will waste is your time if it doesn't so worth a punt

 

[marvoni]

Made a start on it this afternoon but ran out of time.









There were a couple of design changes. The internal baffle plates were a bit over complicated for the tools I have at home so I extended the inlet and outlet pipes just past halfway into the main body and cut them at an angle. I'm hoping this will achieve a similar effect to the baffles. Also I was struggling for fittings so I welded the pipes and the end cap which from a design angle should be fine although I realise my welding won't win any awards. I'll spend some time cleaning them up before I install it.