Water pump leaking

[Mike_87]

Hi I am having problems with my Glowworm Swiftflow 75 (SIT) boiler. Water pump leaks water from under the top of the big screw at the side of the pump. I tried tightening the screw but did not help, water still leaks and pressure falls at rate of 0.1 bar/ day. Do I need a new pump or is there a seal under this screw that I could change? If there is a seal, is it available in shops like Wickes, Screwfix etc. or do I need to look for it on the internet?

 

[JohnKay]

Hi
There is an 'O' ring seal, take it out and have a look, you won't loose much water - honest.
This is not something available from the sheds, plumbers merchants maybe.
That screw is standard on Grundfos pumps, someone may have an old pump laying about.
One last point - are you absolutely sure the leak is coming from there, as it is very rare for this to happen ?

 

[Mike_87]

Thanks for that I will take it out tonight then. I am pretty sure this is where the leak is coming from. The picture attached is not my actual pump, it is there just to show what I mean in case my explanation is not clear enough (English is not my first language). On my pump there is a black circle around the screw and a black line from the screw to the bottom of the pump clearly marking which way water leaks.

I do not think this makes any difference but it only leaks when the heating is off. When the boiler is hot water evaporates very quickly so I cannot see any leaks(but I believe it still leaks). But when I switch the heating off and let it cool down then leaking will start again.

 

[JohnKay]

Mike, as yours is not a Grundfos, please do NOT remove that screw. either come back with a more accurate description of the pump, or get professional help.