Trickle from bathroom sink cold tap need help please

My thoughts were that it is perhaps debris in the pipe to the sink. I completely removed the isolators, checked them and replaced the one to the sink though. I even ran the open pipes for a while and no muck came out.

I'd also have thought that the connecting of hoses and using a vac on the line would have made some difference if it was debris. They made no change whatsoever.

The improvement today only came from draining back down, removing and replacing stuff then turning main back on. The bath that is very close is decent pressure as is the separate mains fed shower in the same room.
 
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Your toilets float valve has an obstruction within it. Fit a new one.
With regards to basin tap ,is it two seperate taps ,one each side of the basin ? If so ,are both slow flowing ?
Or is it a monobloc tap ?
 
Hi, Thanks for the reply. I removed the filler filter for the toilet and cleared it. Barely anything obstructing. The feed pipe flowed ok in to a bowl too, and isolating the toilet makes no appreciable difference to basin tap performance. Toilet fill is still slowish, but not such a big issue. More a problem that the cold tap on the basin is still pretty feeble. It's single taps and the hot which is from the Megoflo is very high pressure Vs the cold which I assume is direct fed. We have no loft tanks. Equiv cold tap in basin in ensuite on other side of house is thunderous, so seemingly not a pressure to first floor issue either.

I'm stumped
 
If the water flow from the cold taps supply pipe ,and Flexi is strong then the tap itself is the issue ,and most likely its valve. Is it a quarter turn tap handle ,or more likely a screw down type.
Same with the WC. If the supply pipe to it has a strong flow ,but water only trickles in to the cistern from the valve ,fit a new float valve.
 
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I replaced the tap internal valve first and no change. Tap body is totally clear and isn’t old as replaced it last year.

Pressure from the flexi wasn’t what I would call strong, but free flowing. Replacement flexi same. No muck came out whilst running it this way but tap performance did improve a bit after putting it back together post another drain down.
 
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Ok ,We don't know EXACTLY what flow you are getting from open ended supply pipe . So ,how many litres ,in one minute do you get from open ended supply pipe ? Then connect isolator and Flexi hose to supply pipe ,but do not connect to tap ,and again measure the flow rate.
As you have told us it's under mains pressure ,once you give the info requested on flow rates ,it will determine where the problem is.
Without it you are going around in circles.
 
Ok thanks I’ll try to confirm that next. What’s a typical amount? Will a Bucket be sufficient usually for the catch test?
 
Try one of your other taps ( not the bath) that run cold well. Depends on a number of things but around 9 litres per minute or more. So if you run tap into a bucket for 30 seconds ,expect 4.5 litres,if your with me.
 
Hi, managed to get a quick look today.

There is definitely an issue on the line in the bathroom for this sink and toilet.

I am getting a gentle 4 litres per minute from the tap line.

The equivalent basin tap line in the other bathroom delivered fiercely 7 litres in 30 seconds!

What next? Some form of pipe flushing needed?
 
Appears to be a restriction upstream of the tap in question. Follow the cold pipe run ,looking for valves ,stop cocks,check valves etc. What diameter is the pipe run to basin tap ? There are not many reasons why an open ended pipe run ,under mains pressure ,will give such poor flow......
1.physical obstruction inside the pipe .
2.partially closed valve.
3.dramatic reduction in the internal bore of pipe ,upstream of the open ended test point. ( Crushed pipe for instance)
As your problem appears to have originated at the time that you fitted a tap / isolated pipework/ drained down etc. 1and 2 are most likely.
 
Ok thank you

Seems it must be a physical obstruction in the run, as all valves are replaced etc. Of course the pipework is under the nice fitted flooring and in the wall behind tiles.

House is a 2012 'new build' so has plastic for the main runs, joined to regular size 15mm? copper pipes which come out of the wall behind the basins and steel flexis from the copper outlets to the basins. This I replaced with basically no gain.
 
Reading thru earlier posts ,it appears that you experienced a problem with basin / WC ,after you replaced a valve in the bath cold tap. That would be a possible opening into cold pipework ,via the bath tap. Possible you allowed something to fall in ?
When replacing kitchen tap ,was any pipework cut into ,or pipe end exposed?
Clutching at straws now !!
 
Thanks

I only replaced the valve in the bath mixer. It’s horizontal so nothing fell in as I swapped it and the bath tap seems to work ok since.

Reason for swapping the valve was poor flow there too, but I’ve had that in the past with these valves and keep a stock. New one seemed to help sort it, but maybe an underlying issue with the pipes to all.
 
Fixed it!

So decided to go back over my work with the bath taps as that's when this issue started. Found this nut which I had not touched to be a little loose. Not leaking water (did have a stain underneath so had leaked a bit) but if I wiggled the taps it opened up and water did come out of the joint.

Cleaned that up and tightened. Once back together and water on the basin tap is restored to a very pleasing gush! I think more so than it ever has.

Can only assume it was drawing some air at the bath taps when I opened the basin or toilet tap? Odd one.

Thanks for your help. This one drove me mental.

Hopefully this is the end of it.
 

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