Water pump Grundfos fails to switch on

kozak

Hello

Water pump Grundfos in our apartment started to play up. Usually it switches on 1 sec after tap is open.

However, recently it takes 5-10 sec, or pump does not switch on at all.
Light knock on the side usually helps , but its not a solution. I’ve done oiling using WD40, did not help.

Any ideas?
Pump is Grundfos STN-2.0 B, bought new for 670 eur 2 years ago. Previous pump worked fine for 7 years.

Thanks

Ravenid

kozak wrote: »

Hello

Water pump Grundfos in our apartment started to play up. Usually it switches on 1 sec after tap is open.

However, recently it takes 5-10 sec, or pump does not switch on at all.
Light knock on the side usually helps , but its not a solution. I’ve done oiling using WD40, did not help.

Any ideas?
Pump is Grundfos STN-2.0 B, bought new for 670 eur 2 years ago. Previous pump worked fine for 7 years.

Thanks

You may have had an issue with the water reaching the pump.
If it runs dry it will need to be reset.

Turn the power off to the Pump at the Fuse board or if it has a dedicated power switch use that.

Give it about a minute and then turn on again.

The pump should come straight back on.

Calahonda52

Could be the capacitor, easy enough fix.

Is the stn an neg head pump?

K.Flyer

STN is a negative head pump.
Is it only connected to the shower or is it connected to the complete bathroom?
If its connected to everthing, is the problem only with the shower or all the taps as well?
If its mainly the shower having the problem then there may be a problem with the pressure switch, as they can sometimes be a bit iffy on that model.

kozak

Thanks for your replies.

Tried to reset pump by turning the power off at the Fuse board – did not help.

Pump is connected to 2 bathrooms and kitchen tap. problem with everything - both showers and all the taps.

Thanks

K.Flyer

Does it make any noise when it's not starting.

kozak

No noise when pump not starting.

kozak

Any suggestions on water pump issue?

K.Flyer

It needs to be looked at to asertain where the problem is.
Could be...
Capacitor,
PCB,
Pressure Switch(es),
Flow Switch(es),
Burnt out motor,
Have you checked the fuse?

kozak

Thanks for suggestions, much appreciated.

Yes, I've checked the fuse.

kozak

Update:

For 2 last days pump does not switch off. We remove fuse to stop the pump.

What is wrong?

K.Flyer

kozak wrote: »

[...]
However, recently it takes 5-10 sec, or pump does not switch on at all.
Light knock on the side usually helps , but its not a solution.[...]

kozak wrote: »

Update:

For 2 last days pump does not switch off. We remove fuse to stop the pump.

What is wrong?

Relay on the printed circuit board stuck in "on postion, from hitting it to get it to start, pressure switch failure in "on" position or flow switch stuck in "on" position.

kozak

Thanks for reply.

Unfortunately I have no idea how switches you've mentioned look like. May be you have a photo or website with pump details?

K.Flyer

kozak wrote: »

Thanks for reply.

Unfortunately I have no idea how switches you've mentioned look like. May be you have a photo or website with pump details?

They are not switches that you can physically turn on or off manually.
Ãt this stage you really need a pump tech to take a look at it for you.

kozak

Would you please recommend good pump tech as our plumber as puzzled by this as we are.

K.Flyer

What area are you in?

kozak

My apologies for the delay.

We live in Tullyvale, Dublin 18. LUAS Cherrywood is 300m from our apt. I'll pm mobile.

when technician can visit us? what price is a visit?