Grundfos Pump Failing?

dinger71uk · 4 Oct 2007

I have a potterton suprima 30 with the new circuit board but since firing up my rads for the winter i have a banging noise which occurs after about 30 mins of use. The banging seem's to be coming from the pipe that feeds the pump and boiler.

All radiators have been checked for air and i have also checked the fe tank and that seems fine. Fluid in fe tank and radiators are very clear.

Im starting to lean towards a pump issue I have a grundfos upc 15-50 (8 years old) when switched down to speed one the noise disappears but raising it to speed 2 or three and the banging returns. I would leave it at speed one but the last two rads on the end of the circuit tend to remain very cool and never really got overly warm. i've removed the centre screw on the pump to see if there was any air but only a slight hiss and no sludge.

Any pointers would be greatly appreciated

Breesey · 4 Oct 2007

Is the pump actually spinning?

dinger71uk · 4 Oct 2007

The pump seems like it is spinning, most of the rads are getting hot.

gas4you · 4 Oct 2007

Is this 30 minute time when the stat turns the heating off? Could be your new pcb is not supply the pump over run time. If you turn the heating off does the pump continue for around 5 - 6 minutes?

Vic Spanner · 4 Oct 2007

Is there a by-pass on the system thats closed

dinger71uk · 4 Oct 2007

pump does overun on boiler going off for about 5 mins, have done some more tests and both water and heating have the same issue with the banging, it seems the banging is located along the flow pipe and seems to be when the boiler gets to a certain temp.

gas4you · 4 Oct 2007

Check, if you can, that the pump is still spinning at high temp. As in another post tonight, I am wondering if it is starting to sieze when getting hot, therefore reducing flow and causing the banging.

Banging is usually lack of flow for some reason.

dinger71uk · 4 Oct 2007

Is there an easy way i can check that the pumps still spinning at high temps?

gas4you · 4 Oct 2007

Undo the large silver screw in the centre and insert a flat bladed screwdriver, it will soon catch and rattle if it is spinning.

dinger71uk · 5 Oct 2007

Seems the pump is still spinning at high temps, but after removing the centre screw and maunally spinning the pump the noise stopped, until it fired up the next morning. Its very weird

diynot

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Grundfos Pump Failing?

Similar threads