submersible pump in a cistern

[Dennis Corvin Blackburn]

in my community there is a well down below that feeds some homes and also pumps water up to a cistern that feeds water to my house and a neighbors. I have a 3600 watt solar inverter and when the well pump in the cistern kicks on it messes up the inverter. I am replacing the current pump with a 110V 1/2 horse Grundros slow start pump. this pump is suppose to work with a 1500 watt inverter. it pumps 10 gallons per minute. will this be enough for two homes. the pump sends water to an 80 gallon pressure tank. also any tips on how to get the old pump out and the new one hooked up would be appreciated. the opening for the cistern is 15 inches so I doubt if anyone can squeeze through that. thanks in advance

 

[Reach4]

As I understand it, a submersible pump in the well fills your cistern. That pump is run by somebody else, and you are not replacing that. You have a pump within the cistern that distributes that cistern water to two houses. You are replacing that with a 1/2 HP 10 GPM slow start submersible pump that you have already selected. So that is moot.

So your question is how to remove the existing pump that is in the cistern itself, and replace that with the pump that you have not quite named (such as Grundfos SQFlex ) within the cistern. May we presume that both the old pump and new pump are both submersible pumps that are horizontal in operation. The reason that you are replacing that existing pump is that it puts your inverter into a bad state (probably drawing more power during startup than the inverter can handle).

You should post a photo and/or a sketch that shows the situation. If the pump were just sitting on the bottom on a pipe, I presume you would figure to pull on the pipe and bring the pump up that way. So I presume the situation is more complex than that.

 

[Sponsor]

 

[Dennis Corvin Blackburn]

As I understand it, a submersible pump in the well fills your cistern. That pump is run by somebody else, and you are not replacing that. You have a pump within the cistern that distributes that cistern water to two houses. You are replacing that with a 1/2 HP 10 GPM slow start submersible pump that you have already selected. So that is moot.

So your question is how to remove the existing pump that is in the cistern itself, and replace that with the pump that you have not quite named (such as Grundfos SQFlex ) within the cistern. May we presume that both the old pump and new pump are both submersible pumps that are horizontal in operation. The reason that you are replacing that existing pump is that it puts your inverter into a bad state (probably drawing more power during startup than the inverter can handle).

You should post a photo and/or a sketch that shows the situation. If the pump were just sitting on the bottom on a pipe, I presume you would figure to pull on the pipe and bring the pump up that way. So I presume the situation is more complex than that.

the pump is a grunfrosSQ that was recommended by three solar companies. the current pump is horizontal but the grunfros will be vertical, placed in a pipe to simulate being in a well. I imagine there will need to be some pipe shifting around to make things fit. the person doing it said it is about a three hour job

 

[Reach4]

In that case, would go horizontal with the pump in a 3 inch PVC or ABS sleeve with the pipe end blocked and the bottom open. The main purpose of that pipe (called a shroud or flow inducer) is to get water to flow by the motor on its way to the pump inlet. Drain pipe is OK. I am not a pro.

https://terrylove.com/forums/index....-pump-in-cistern-mounting-installation.23621/ shows holding the pump off of the bottom. I think maybe smaller pipe could be used for the underneath part, since there should not be much debris in your cistern.

Maybe while the cistern is being worked on, it would be a good time to clean the cistern. I am not sure what the best tool for that would be. Also think about sanitizing your system after the work is done.

 

[Valveman]

In that case, would go horizontal with the pump in a 3 inch PVC or ABS sleeve with the pipe end blocked and the bottom open. The main purpose of that pipe (called a shroud or flow inducer) is to get water to flow by the motor on its way to the pump inlet. Drain pipe is OK. I am not a pro.

https://terrylove.com/forums/index....-pump-in-cistern-mounting-installation.23621/ shows holding the pump off of the bottom. I think maybe smaller pipe could be used for the underneath part, since there should not be much debris in your cistern.

Maybe while the cistern is being worked on, it would be a good time to clean the cistern. I am not sure what the best tool for that would be. Also think about sanitizing your system after the work is done.

Actually a "sleeve", "shroud", or "flow inducer" pipe over the pump needs to be sealed at the top, above the intake, and open ended at the bottom. I don't think you need a shroud for an SQ pump, as it has an internal circulation system to keep the motor and electronics in the motor cool. The motor is filled some some kind of lubricant called SML-2, which is circulated to keep the motor and electronics in the motor cool.

Also it is not a problem to install these pumps horizontally in the bottom of the cistern.

See this quote.

Over temperature protection
A permanent magnet motor gives off very little heat to its surroundings. In combination with an efficient internal circulation system leading the heat away from the rotor, stator and bearings, this ensures optimum operating conditions for the motor.

As an extra protection, the electronic unit has a built-in temperature sensor. When the temperature rises too high, the motor is cut out; when the temperature has dropped, the motor is automatically cut in again.