Grundfoss pump stops for 1 sec during use

yop

Hi
We have a grundfos pump to pressurise the whole house.

We had a kitchen tap that was leaking for a few weeks until I had time to rip it out and replace it.

Now the pump during use, will stop pressurizing for maybe 1 or 2 seconds, then pressurize for 10 seconds, then stop, etc etc.

Any ideas on what a fix might be for it?

Thanks

Joey the lips

No sorry. Have you called grundfos. They are usually very helpful with this stuff

yop

Joey the lips wrote: »

No sorry. Have you called grundfos. They are usually very helpful with this stuff

Thanks Joey. I did that there, have some great documents online but I didn't get an answer to work.

Thanks for coming back to me.

pipers

Repressurise the expansion vessel(s).

yop

pipers wrote: »

Repressurise the expansion vessel(s).

Is that achievable without any specialized tools?

Thanks for the reply.

heinbloed

Well, to repressurise the expansion barrel you could use a standard foot pump similar to a car tire pump.

But check the pressure of the water pipe first: there should be a manometer near the pressure barrel showing the actual pressure in the water pipe.
Let the water run, the tap open. This should kick-in the pump sooner or later. Check at what pressure this happens. After kicking-in the pump creates a certain pressure before the pressure sensor tells it to stop working.Now the pressure will drop again,until the pump gets a signal to kick-in again. And so on.

From what you tell in your first post

...the pump during use, will stop pressurizing for maybe 1 or 2 seconds, then pressurize for 10 seconds,....

it looks as if this sensor is either defect or de-ranged, giving wrong signals. The membrane in it could be leaking or the minimum-maximum setting simply needs to be re-adjusted.

After checking the pressure by watching the manometer in action ( if this is working correctly, showing correct results) it is very likely that the pressure barrel is defect - as pipers said already. It could be sludged up or be underpressured.

Check the pressure at the expansion barrel at least once pear year, a simple tire pressure gauge for €5-10 from the garage will do. If you have a foot pump there is one with it, use this.

So check the minimum and maximum pressure of your water system first.

sullzz

You will need to repressurise it with the vessell empty of water usually a foot pump will do , is it a grundfoss mq3 pump

yop

Thanks lads.
Thats it, the MQ anyway, not 100% exactly which model, I can't spot it as its tight enough to the wall.
I downloaded all the manuals but can't see any access to pressurize it.

Had a look at it there and I can't any valve to attach the pump to and there isn't any pressure gauge on the pipework to see if I could see anything.

Actually how do I empty it? Just turn the water off and run the tap is it?

Thanks

heinbloed

Mmh...

Better get a plumber in to have a look at it. There are well borers/ installers who'll manage to get you water to the house as well.

The pressure at the expansion barrel can be meassured and adjusted at the valve. This looks like a car tire valve. Either sticking out or inserted in the barrel, at the air-side of it.

Check "google pictures" or the like to see what it loks like.

Actually how do I empty it? Just turn the water off and run the tap is it?

To empty the water pipe disconnect the pump from the electricity ( switch-off the fuse) and open the tap.
Now you can meassure the pressure in the air bag of the expansion barrel.
This should match the pressure wanted in the water pipe.

yop

heinbloed wrote: »

Mmh...

Better get a plumber in to have a look at it. There are well borers/ installers who'll manage to get you water to the house as well.

The pressure at the expansion barrel can be meassured and adjusted at the valve. This looks like a car tire valve. Either sticking out or inserted in the barrel, at the air-side of it.

Check "google pictures" or the like to see what it loks like.





To empty the water pipe disconnect the pump from the electricity ( switch-off the fuse) and open the tap.
Now you can meassure the pressure in the air bag of the expansion barrel.
This should match the pressure wanted in the water pipe.

Thanks for that, this is the exact one, no valve on it that I could see.

http://www.grundfos.com/products/find-product/mq.html#contact

pipers

It's inside the black cap.
Also charge the other vessel(s)

yop

pipers wrote: »

It's inside the black cap.
Also charge the other vessel(s)

I found that ya. I put the foot pump on it there to see and its sitting around 60psi

I gave the pump 2 pushes and I tried the water again, which seems to have reduced the timeout of power to less than a second. I don't want to mess around with it anymore though so not keen on giving it any more "pumps"

JohnnieK

The MQ does not have an expansion vessel, It's possible there is a faulty pressure switch or the pcb. Are you sure you tightened the nuts on the tap you changed. I'm surprised with Grundfos not getting back to you.

yop

Aye, brand new taps went in and well tightened.

2 days later and no word from them.

JohnnieK

I'd ring them again next week. They are normally very good. I normally dont have any problems with MQ's.

yop

Thanks JohnnieK, its been sound for the last 6 years, its just played up with the leaking tap in the kitchen. Its not a mile away now giving it them 2 pumps today, but I am wary of messing around with it.

JohnnieK

To be honest I would say it's just a big coincidence regarding the tap. Best of luck:)

sullzz

JohnnieK wrote: »

The MQ does not have an expansion vessel, It's possible there is a faulty pressure switch or the pcb. Are you sure you tightened the nuts on the tap you changed. I'm surprised with Grundfos not getting back to you.

Grundfoss call it a pressure tank , same as an exp vessell and often needs to be re-pressurised

yop

Grundfos came back this morning, said it would be a flow wheel which is gone, 58euro ex VAT and delivery.
Going to have to go with it and see.

No sign of it on the 2 PDF docs I downloaded off their site so need to figure it out a bit!