I have questions - Borehole supply at Salvation Army

Water
1

This morning I was at the Salvation Army hostel in Emmarentia. Not that I am any kind of expert, but it’s a weekend and they had things going on they didn’t understand and they needed somebody to give them some kind of idea.

OK. Long story short: This hostel suffered badly during last year’s water shortages in Jhb. At this point another charity, Mission of Mercy, stepped in and very generously provided a borehole, jojo tank and integration with the hostel’s water supply.

They still have access to municipal water, but can turn that off.

As far as I can understand…

  • There is a combiner for borehole and municipal water
  • There are two valves, for opening or closing each water source
  • The output of this is the input into the jojo
  • The water is then pumped out of the jojo, through filters and some sort of sanitisation system (has a UV warning sticker on it) and into the property.

Now the first thing is that that pump runs ALL the time (load shedding excepted). Can that be right? It has a device on it that looks like it turns the pump on and off according to demand.

pumpThing
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This makes sense. If you keep on pumping water into the pipes, and there is no demand for water, then the pressure will build and build. So how come this pump runs ALL the time? This to me says “leak”.

I am supported in this (I think) by the following.

  1. Turn pump off
  2. Go back to the combiner. Turn borehole water off. Turn municipal water on.
  3. The meter now starts spinning like a top.

Given that the output of the jojo is the input to the building, I suspect this leak (or leaks) is in the building, not underground. In fact I quickly found 5 leaks (and I’m no plumber). Most looked small, and three could likely be fixed by replacing washers on taps.

OK… the other problem they have is that when there’s load shedding, there’s no water, because the pump won’t work.

The pump is marked at 1.1 kw. The purifier I mentioned is marked at 55W. I’ve heard talk of solar powered pumps for boreholes. There is north facing roof very close to the pump. But I don’t know what’s involved in “solarising” this system. Does the pump have to be changed?

Some of the residents are unhappy because they can’t get a shower when there’s load shedding. The management are unhappy because the home is not cash flush, and they would like the residents to all work with them to bring running costs down. Meanwhile that pump is working (at present) for about 18 hours a day. So 18 * 1.1 * 30 = a non trivial addition to their electricity bill.

I would appreciate any inputs anybody has to offer. The home needs a plan of action, but we’re all groping around in the dark here.

2

If the pump is running it means that it isn’t reaching set pressure that indicates that their is a leak.
The solar pump will help but what will not help when it is overcast or night. Maybe look at placing the tank on a stand? This will also mean that the geyser must be changed to low pressure seeing that the tank will not provide enough pressure for a normal geyser. Other option is a Solar Backup system but that is going to be expensive.

3

Thanks, Jakes. My own guess had been that there must be a leak, because if that pressure controller had failed, the plumbing would be climbing out of the walls by now.

The plumbing set up is very complicated. I saw 3 geysers, and there may be more. This is a home with 20 or more residents, and also some retired officers of the Salvation Army. One of the geysers is solar heated. There’s also a heat pump which, I’m told, no longer works. I’m thinking that getting that fixed won’t save them money in the long term. But it’s not my money I’d be spending.

I think that once the leak is addressed, the solution is fairly simple: during power outages, switch to the municipal water supply.

I think that at some point a plumber is going to have to get involved. That’s not me!

4

Maybe this can help. This is wat I did at my own home.
Both Municipal and the pump can feed the house but theirs also 2 non return valves installed. This allows the system to use what is available at that time. If pressure is to low from Municipal the pump will start and seeing that the water wants to flow back the non return closed and pressure my home system. This is more automated and no need to close and open valves by hand.

5

Thanks again. They have two valves that must be opened or closed by hand. It is possible for both to be open at the same time, which doesn’t seem to be a good situation to me. My thinking - and I stress that I am not a plumber - is that whichever source has the highest pressure will push back into the other.

6

It’s actually illegal. You should have a RPZ valve fitter (like two check-valves, but venting to atmosphere in the middle) to be compliant.

At the very least you should have a check valve so reverse flow is not possible. Quite often the water meter will have one built in already, but you cannot necessarily rely on that.

7

Thanks. I need to go and have another butcher’s at this. I took lots of pictures of the jojo end of things, I have none of the other end.

8

Thanks to all who have given input here.

I noted earlier that I found 5 leaks fairly quickly. Staff at the home have since found another 11. So first priority is to address the leaks.