Installing Submersible Pump in Tank

[carlyai]

I bought a submersible pump that I didn't use. It is a Saxon 750 W, not one of those thin stainless ones for bore holes but a bulky one with a base.

I want to feed my irrigation system with a larger pump and was thinking of putting this pump inside the 2000 L  water tank instead of buying a new centrifugal pump (cheap charlie). The tank is not stainless, one of those brown ones.

Will the start torque of the pump cause issues or scaring of the tank?

Can you think of reasons not to do this?

[Artisi]

No reason why you shouldn't use it inside your tank. 

[Crossy]

I agree, no reason why you shouldn't put it in your tank.

 

Do make sure it's protected by an RCD/RCBO, I have had low cost submersibles (actually 2 pukka pond pumps) slowly let the damp in when continuously under a metre or so of water.

   

[sometimewoodworker]

35 minutes ago, Crossy said:

I agree, no reason why you shouldn't put it in your tank.

 

Do make sure it's protected by an RCD/RCBO, I have had low cost submersibles (actually 2 pukka pond pumps) slowly let the damp in when continuously under a metre or so of water.

   

It’s not going to affect this situation but I have a pump that’s going to get fixed soon, where the cable has been nibbled by a turtle so allowing an occasional short, blowing the RCBO.

[Crossy]

2 minutes ago, sometimewoodworker said:

It’s not going to affect this situation but I have a pump that’s going to get fixed soon, where the cable has been nibbled by a turtle so allowing an occasional short, blowing the RCBO.

 

How big are your turtles??

 

[sometimewoodworker]

1 hour ago, Crossy said:

 

How big are your turtles??

 

About the same size or a bit smaller than our kitten & if out of the water she might have done the deed.

[Artisi]

Just side tracking a little:

after many many years involvement with quality submersible pumps - including sewage, bore-hole, contractor site pumps, etc - one of the major points of failure is the power cable, especially the el-cheapo units supplied in a cardboard box off the shelf of your local hardware store. 

These cables are not able to with-stand much abuse and can lead to major failure. 

As Crossy pointed out RCBO is a must. 

[ourmanflint]

19 hours ago, carlyai said:

I bought a submersible pump that I didn't use. It is a Saxon 750 W, not one of those thin stainless ones for bore holes but a bulky one with a base.

I want to feed my irrigation system with a larger pump and was thinking of putting this pump inside the 2000 L  water tank instead of buying a new centrifugal pump (cheap charlie). The tank is not stainless, one of those brown ones.

Will the start torque of the pump cause issues or scaring of the tank?

Can you think of reasons not to do this?

Wouldn't a 750W pump empty your tank in a matter of seconds?

[sometimewoodworker]

4 hours ago, ourmanflint said:

Wouldn't a 750W pump empty your tank in a matter of seconds?

The usual output pipe is between 1 ¼” and 2” so probably at least 15 minutes.

 

To empty a 2,000L tank in seconds you need a much larger pipe, probably 10”+ ???? 

 

[Crossy]

Yeah ^^^, our 2.2kW irrigation pump (not submersible) will empty the 2400L buffer tank in about 5 minutes given the chance (2 x 2" pipes, all the sprinklers on).

 

We only run two of the big squirters at once to get adequate squirt range and to allow the 2HP lift pump from the canal to keep up.

[ourmanflint]

7 hours ago, sometimewoodworker said:

The usual output pipe is between 1 ¼” and 2” so probably at least 15 minutes.

 

To empty a 2,000L tank in seconds you need a much larger pipe, probably 10”+ ???? 

 

I did wonder, as an aquarium buff, I know a 200w 25000lph pump would empty a 2000l tank in less than 5 minutes through a 1.5" pipe. Greater head and longer pipe run will make a difference.

[HashBrownHarry]

On 11/26/2020 at 9:20 AM, sometimewoodworker said:

About the same size or a bit smaller than our kitten & if out of the water she might have done the deed.

how big is your kitten - lol

[sometimewoodworker]

11 minutes ago, HashBrownHarry said:

how big is your kitten - lol

Kitten tax

[carlyai]

18 hours ago, ourmanflint said:

I did wonder, as an aquarium buff, I know a 200w 25000lph pump would empty a 2000l tank in less than 5 minutes through a 1.5" pipe. Greater head and longer pipe run will make a difference.

Output will be throttled down. So the water will go initially into a 2" pipe that I dug in the ground when I put in the pool piping. 

Because wifey keeps adding sprinklers to our mini-sprinkler setup I need more water pressure or a rearrangement. From the 2" pipe it will end up in a .5 " pipe. I'll adjust the flow so the sprinklers don't take off.

The tank has float switches and refills from the aquifier.

[sometimewoodworker]

6 minutes ago, carlyai said:

From the 2" pipe it will end up in a .5 " pipe. I'll adjust the flow so the sprinklers don't take off.

Don’t reduce the size of the pipe. It’s a mistake to think that reduced size will maintain the pressure. There is a thread here some time ago where the poster had done that but had to dig out the supply pipes and increase the size back to all the same to allow good flow to all the sprinklers.

[carlyai]

1 hour ago, sometimewoodworker said:

Don’t reduce the size of the pipe. It’s a mistake to think that reduced size will maintain the pressure. There is a thread here some time ago where the poster had done that but had to dig out the supply pipes and increase the size back to all the same to allow good flow to all the sprinklers.

The supply pipes are 2", but the mini-sprinkler already installed along the pool fence and a bit of the boundary fence is .5" black irrigation pipe tubing. It's on a 12 hr timer and split between the pool fence plants for 20 min, then boundary fence for 20 min. Trouble is wifey needs more sprinklers for more plants and the 350 W pump supply on won't do it.

[sometimewoodworker]

2 hours ago, carlyai said:

The supply pipes are 2", but the mini-sprinkler already installed along the pool fence and a bit of the boundary fence is .5" black irrigation pipe tubing. It's on a 12 hr timer and split between the pool fence plants for 20 min, then boundary fence for 20 min. Trouble is wifey needs more sprinklers for more plants and the 350 W pump supply on won't do it.

OK so it’s irritation tube not sprinklers, the same principle applies, if you put in a larger diameter irrigation tube your current pump will be able to supply a longer run of the tube. If you stay with the current diameter tube you will need a higher flow (possibly higher pressure as well) to power a longer run.

So it’s decision time, second pump or replace the tube.

[carlyai]

4 minutes ago, sometimewoodworker said:

OK so it’s irritation tube not sprinklers, the same principle applies, if you put in a larger diameter irrigation tube your current pump will be able to supply a longer run of the tube. If you stay with the current diameter tube you will need a higher flow (possibly higher pressure as well) to power a longer run.

So it’s decision time, second pump or replace the tube.

It's taken me 3 years to get the small sprinkler (they are sprinklers, different ones for different jobs) in. The plan was (6 years ago) to install all the 2" pipes in the area and then make up a 4 zone microprocessor controlled and valves to make it all work coming from the front bore pump. I did a lot of the research about 6 years ago. So I did get some 2" pipe in, but wine, women and song got in the road. Then because of the wine, women and song I had operation, operation and operation. 

So now it's past Plan C and we're up to Plan D. ????

It's like my aquaponic test kit, bought it a few years ago and now when I am getting round to using it, it's out of date .