Hi Guys,

I've got a developer-supplied water pressure system modeled Grundfos CM-PT installed on a 3-storey link house. Just moved in, it was working fine for a month, and now the pump runs continuously without stopping. Sometimes the low rumbling sound also accompanied by groaning sound. There's a switch that I used to turned it on 24/7, but now due to the incessant sounds from the pump, I had to turn it off whenever water is not used.

Is it normal for a water pump to run continuously...? Previously it only runs intermittently when water is used especially on top floors.

No.

No, it's leaking.

Gonna take few times to find out which part is leaking.
The worst part and probably a nightmare to find it.

And check your water bill too.

doesn't have to be just leakage through the pipes..

The non return valve could be defective allowing water to leak back ..

thus the pump pressure switch cannot detect a set pressure to stop pump..

or maybe a faulty, stuck or dirty switch..

try washing out the switch and testing the non return valve first

Quite sure it is faulty pressure switch. Should get them check again and ask for warranty

In my case, the pipe had a small crack and was leaking slowly. Pump won't stop. Electricity and water bills also went up.

How is the pump running sequences?

1. Run non stop

or

2. Run>stop 1~3sec>Re-run

Scenario 1:
- Pressure switch on the pump faulty.
- Pressure vessel on the pump damages (no longer pressurized)

Scenario 2:
- Check valve damaged, causes backflow
- Pipe leakage

Above are the possibilities based on my experiences.

I have a joven central pump. Early one morning I heard the pump activating and stopping in intervals, continuously. But there was no one using the bathroom. I went to check the shared bathroom and water was dripping from the tap. I applied pressure on the tap and the dripping stopped and so did the water pump. Need to change the washer of my tap.

Must be something leaking..
Please check that out...

either leaking or air trap in your piping.
did you emptied your water tank some time this month?

if yes, then you will need to purge the air trap first

Some times it is cause by other simple factors such as tap is not properly turn off, wc flush spoil and etc.

Check all these simple things 1st before further investigate which might cause a lot of hassle.

This post has been edited by enriquelee: Sep 25 2017, 10:51 AM

You were right... Found the problem... Someone itchy-handed and switched the toggle of my water filter to "Stop" position. I ended up draining my entire water tank...

Good that you found your problem and solve it hassle free.

I have asked the developer-appointed contractor to check the pump just in case...

Thanks for all the input guys... Appreciate them...

Hi I'm having a similar problem after installing a water filter. Pump running even using only small amount of water which previously only after open a few tap only the pump will run. Any idea?

Check tank

How's your TNB bill? Very high?

Get a water pump technician to check if the cut-off switch is faulty...

Hi k sifus, i am facing similar issue now where my water pump wont stop running. Noticed this issue this morning when water is scalding hot but water pressure is still strong.
Have checked all outlet in the house but no leakage. Went to the pump itself and saw leakage at the pump inlet. Does the leakage at the inlet causes the pump to run continuously? Or is there other underlying issue?

Does your pump have a valve like on the bicycle tyre. You need to take a bicycle pump and pressurise to 30psi.

My Grundfos pump had continuous running issue was caused by the pressure switch needs the back pressure. After I pump the air in Now working normally again.

This post has been edited by jetblast: Nov 8 2021, 02:00 PM