Rain harvesting troubleshooting

CoreyTroy · Nov 05, 2024 4:53 pm

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I have an on-going issue with one, and only ever the one down pipe on my house
Aa owr the picture, under heavy rain, it always pours water out.
I have removed the minor internal mesh inside the leaf trap.
I have also added 2 x extra downpipe on that side of the house to try to rectify, but to no avail.

Background info
My house is split into 2 x intakes to 2 x 22,500ltr tanks.
The south side has 4 x downpipe.
The north side had 2. But after I added 2 x more, I now have 4 also.

I need assistance to troubleshoot the issue.

Not sure what else I need to supply to help.

Corey

SaveH2O · Nov 05, 2024 5:18 pm

Are leaf diverters fitted to all downpipes and are they all at the same level?

Is the problem leaf diverter (shown) the one that is furthest from the house?

When it isn't raining, at what height below the leaf diverter is the retained water level?

CoreyTroy · Nov 05, 2024 5:58 pm

SaveH2O

Are leaf diverters fitted to all downpipes and are they all at the same level?

Is the problem leaf diverter (shown) the one that is furthest from the house?

When it isn't raining, at what height below the leaf diverter is the retained water level?

The one shown is the one that used to be the closest to the tank. Now it is the 3rd from the back, 2nd from the front.

I will have to check the level of the resting water. But visually the leaf diverters look level with each other.

SaveH2O · Nov 05, 2024 6:35 pm

If it isn't a head issue, it will invariably be a blockage. Given that it isn't the furthest downpipe from the tank on the carrier pipe, the blockage has to be in the downpipe.

Is the outer mesh a coarse screen with apertures about 6-8mm across?

SaveH2O · Nov 05, 2024 9:54 pm

When you check how far below the leaf diverter the standing water is, can you also do a comparison check with the other downpipes that divert into the same carrier pipe thanks.

CoreyTroy · Nov 06, 2024 2:56 pm

SaveH2O

Is the outer mesh a coarse screen with apertures about 6-8mm across?

Yes they are.
The internal mesh is a lot finer, about 1mm.

I am going to cut down pipe later today, and lift the elbow about 80mm, as the run from the bottom of the down pipe into the main piping is only a very slight slope.
The other pipe work have a much shorter run to the main pipe, and are thus on more of a drop.

I also will see if I can raise the leaf trap to slide it up between the gutter and facia, but I will have to trim the corner, as the guttering changes direction there and is currently preventing it going up higher.

Will update when done.

SaveH2O · Nov 06, 2024 4:09 pm

Here is a similar one except that this one overtops (insufficient hydraulic head) whereas yours pushes water forwards which indicates that the bottom of your upper downpipe is angled to divert the water forwards , something I have never seen before. Is there any chance that you can post a photo showing the upper downpipe and the coarse mesh screen?
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CoreyTroy · Nov 06, 2024 10:59 pm

So I cut and raised the angle of the base of the downpipe today, so the fall from the bottom of the downpipe elbow now is around 80mm,to where it connects into the main pipe travelling to the tank.

Not sure if this will fix it. But the current fall was only around 10mm over a distance of about 3mtrs. Not it is around 80mm.

Will not tell if fix until next storm, hopefully in the next few weeks.

Water levels compared to the other down pipes were the same. And the down pipe I shortened was clear of all blockages too.

SaveH2O · Nov 07, 2024 6:04 am

CoreyTroy

So I cut and raised the angle of the base of the downpipe today, so the fall from the bottom of the downpipe elbow now is around 80mm,to where it connects into the main pipe travelling to the tank.

Not sure if this will fix it. But the current fall was only around 10mm over a distance of about 3mtrs. Not it is around 80mm.

If I am understanding what you have done, the change will make little difference because the height of the water column hasn't changed. Most friction loss will occur at the carrier pipe - downpipe interface.

See video below. The explanation starts at 36 seconds.

Boil Water at Room Temperature! - Hydrostatics

CoreyTroy

Water levels compared to the other down pipes were the same. And the down pipe I shortened was clear of all blockages too.

And there is another downpipe upstream that doesn't overflow?

The diverter's overflow characteristic isn't normal.

CoreyTroy · Nov 07, 2024 8:44 am

SaveH2O

CoreyTroy

So I cut and raised the angle of the base of the downpipe today, so the fall from the bottom of the downpipe elbow now is around 80mm,to where it connects into the main pipe travelling to the tank.

Not sure if this will fix it. But the current fall was only around 10mm over a distance of about 3mtrs. Not it is around 80mm.

If I am understanding what you have done, the change will make little difference because the height of the water column hasn't changed. Most friction loss will occur at the carrier pipe - downpipe interface.

See video below. The explanation starts at 36 seconds.

Boil Water at Room Temperature! - Hydrostatics

CoreyTroy

Water levels compared to the other down pipes were the same. And the down pipe I shortened was clear of all blockages too.

And there is another downpipe upstream that doesn't overflow?

The diverter's overflow characteristic isn't normal.

Interesting video.
Maybe I need ti look at raising the leaf guard also if I can. I could possibly only get about 50mm though.

SaveH2O · Nov 07, 2024 9:38 am

Are you off the water grid?

The amount of water that is lost is considerable and the leaf diverter's overflow characteristic is weird. I also don't understand why the upstream leaf diverter isn't overflowing.

Given that you have leaf diverters and provided you fit the mosquito proof mesh back into the leaf diverter that overflows, I suggest fitting a 50mm ball valve 150mm above the bottom of the tank to supplement the wet system's discharge capacity. A strong, flexible, UV stabilised pond hose or similar would connect the ball valve to the wet system pipe. If it is a round tank, the valve should be fitted between 30 and 75 degrees to the side of the valve that supplies the pump.

The minimum amount of supplementary inflow will be generated by the additional height difference between the tank's water level when the tank is full and the height of the wet system's vertical riser above the tank. When the water level is less than full, the supplementary inflow will increase due to the decreasing water levels providing more hydraulic head pressure.

CoreyTroy · Nov 08, 2024 6:41 pm

SaveH2O

Are you off the water grid?

The amount of water that is lost is considerable and the leaf diverter's overflow characteristic is weird. I also don't understand why the upstream leaf diverter isn't overflowing.

Given that you have leaf diverters and provided you fit the mosquito proof mesh back into the leaf diverter that overflows, I suggest fitting a 50mm ball valve 150mm above the bottom of the tank to supplement the wet system's discharge capacity. A strong, flexible, UV stabilised pond hose or similar would connect the ball valve to the wet system pipe. If it is a round tank, the valve should be fitted between 30 and 75 degrees to the side of the valve that supplies the pump.

The minimum amount of supplementary overflow will be generated by the additional height difference between the tank's water level when the tank is full and the height of the wet system's vertical riser above the tank. When the water level is less than full, the supplementary inflow will increase due to the decreasing water levels providing more hydraulic head pressure.

Interesting thought and reasoning, but I cannot visualize what you are suggesting. Any pics of this?

SaveH2O · Nov 08, 2024 8:18 pm

SaveH2O

The minimum amount of supplementary overflow will be generated by the additional height difference between the tank's water level when the tank is full and the height of the wet system's vertical riser above the tank.

I just noticed that I wrote "overflow" instead of inflow. I have edited it.

SaveH2O · Nov 08, 2024 8:31 pm

CoreyTroy

Interesting thought and reasoning, but I cannot visualize what you are suggesting. Any pics of this?

There is discussion about fitting a low restriction inlet in many Homeone threads. Just do a forum search using the keywords.

It is simply a tank valve with a flexible hose that connects to a branch off the main infeed/carrier pipe. It has many advantages including supplementing the carrier pipe's discharge capacity.

Logically, the upstream leaf diverters should also be overflowing, it just doesn't make sense that they don't.

Just to confirm, there are TWO upstream downpipes diverting water into the carrier pipe. Is that correct?

CoreyTroy · Nov 12, 2024 2:38 pm

SaveH2O

CoreyTroy

Interesting thought and reasoning, but I cannot visualize what you are suggesting. Any pics of this?

Just to confirm, there are TWO upstream downpipes diverting water into the carrier pipe. Is that correct?

No. Only the one upstream from the one that overflows. It doesn't overflow. It was an addition I added to try to solve this ones overflowing.
But, it did not change it.

We are forecast 10mm rain Thu/Fri this week, hopefully a short downfall in that to test the mod I did last week.