ᐅ Rainwater Harvesting Cistern for Garden Irrigation – Which Pump Should I Use?

rick2018 schrieb:

Use the fittings from Unidelta. They have all the variants you need, for example, T-pieces.
What type of PE pipe do you have?
You don’t need a conduit pipe for the PE pipe.
Of course, you can connect a submersible pump to it. This kind of setup is exactly what such permanent installations are for. Again, Unidelta...
And it’s not complicated either. I have a 63mm (2.5 inch) PE pipe on my submersible pump. It’s really rigid...
I guess you have a DN25 or at most a DN32.

I have DN32 from Controlled Residential Ventilation (Hornbach), and I bought T-pieces and L-pieces from Marley.

1. Conduit pipe, T-piece: The idea behind using conduit pipe is for repair or replacement. But if I have a distributor or T-piece in the middle, conduit pipe doesn’t really help. Would it be better and simpler to install the PE pipe with a T-piece directly underground (without conduit pipe)?

2. Connection to submersible pump: I don’t have a solution yet for connecting to the submersible pump. The 32mm (1.25 inch) pipe is rigid, not flexible. I need to make a 90° connection to the submersible pump, and to do this, I have to bring the 32mm pipe about 1 meter (3.3 feet) up.

To connect, use a 90° fitting. Then lower the pump. Next, install another fitting on top. This way, the setup is easy to replace or service.
Use PE pipe directly in the ground. Depending on the PE pipe, it is certified for up to 100 years.
If the KG pipe is longer than a few meters, you won’t be able to push the PE pipe through it anyway.

rick2018 schrieb:

For the connection, use a 90° fitting. Then lower the pump. Then add another fitting on top. This way it’s also easy to replace or service.
PE pipe goes directly into the ground. Depending on the PE pipe, it is certified for up to 100 years.
If the sewer pipe (KG) is longer than a few meters, you won’t be able to push the PE pipe through anyway.

Thanks for your reply.
Originally, I wanted to implement it like my first plan (see attachment). But here, I have to climb down with a ladder every time for maintenance or repair. I would prefer to avoid that.

Thanks to your suggestion, I believe the second plan is better. However, I need 3 fittings here (instead of 2 as in your text). With this solution, I will probably lose a lot of pressure.

Did I make a mistake in my reasoning?
Maybe you have a better idea?

Plan 1. Fitting should be installed not in the center as shown in the plan, but all the way to the right, or even a bit longer. This way, the pipe will be long enough for you to pull the pump up along with the pipe. This allows you to access the fitting without having to climb down.

A DN32 pipe is not that rigid. Not even a PE100 pipe. If it’s cold, you can warm it up with a heat gun.

In theory, you could also simply make a bend with the pipe inside the shaft without using a fitting at all.
Alternatively, you can use 45° bends, which result in significantly lower pressure loss.
Overall, one or two extra elbows should not make a big difference.
You rarely need to access the pump anyway.

How large will your irrigation system be, and what flow rates do you require? Which pump will be used?

rick2018 schrieb:

Plan 1. Use a fitting, but not centered as in the plan—place it all the way to the right or make it a bit longer. This way the pipe will be long enough for you to lift the pump with the pipe. That means you can reach the fitting without having to climb down.
A DN32 pipe is not that rigid. Not even PE100. When it’s cold, you can warm it up with a heat gun.
Theoretically, you could also just make a bend with the pipe inside the shaft without any fitting at all.
Or you can use 45° elbows. The pressure loss is significantly lower there.
Overall, one or two extra bends shouldn’t make much difference.
You rarely need to access the pump anyway.

How big is your irrigation system, and what flow rates do you need? Which pump will you be using...

Thanks. I will give it a try to see how easy it is to work with. I’m afraid that despite all effort, I won’t manage to bridge the just over 1m (3 feet) depth.
I also thought about a 45° fitting. I found very few or almost no options available (Amazon, eBay). Do you have any other tips for me?

Unidelta. Available from Wolf for about 3€.
Look for Unidelta 45°.