Reduced Flow In A Cold Water Pipe

[duffplumber]

Hi
For some time now there has been a reduced flow in our downstairs loo, in fact the hot water flow is 10 times better.
All cold taps in the house are fed through the rising main. In this instance fed through a pipe in the ceiling void (I think).
This also affects the rate at which the toilet cistern fills up so the likely culprit is lime scale build up (I always thought hot water feeds were more prone to scaling than cold).
I have one of these electrical ionising devices (on the pipe for about 20 years) on the main as it comes into the house, and no other plumbing is affected. Most recent plumbing additions elsewhere in the property are 3 years ago & the oldest are 26 years (including this stretch).
Is there anything I might do to avoid replacing the stretch of pipe from the main to the downstairs loo?

 

[Dotty]

Check the ballvalve. You may have a build up of detritus in the seat. Replace the washer while you're at it.

 

[AWheating]

like croppie said check and possibly replace washers, also check any valves are not blocked up. (iso valves, stop taps etc....)

 

[duffplumber]

Thanks for the replies guys, but I've done all that in fact I installed a new syphon (old one failed) & new ball valve assembly a little while ago. A new stopcock was installed a couple of years ago, and is as far as I can detect, working fine (it shuts the water off & allows it back on again - what else?). So I'm sure the issue is something (loose lime scale from somewhere else in the pipe run lodged) has reduced/impeded the flow along the pipe.
I do have an isolating valve entering at the point at which the pipe feeds water to the cistern, but I've checked that too & it seems to be working fine. The fact that the cold tap is also affected as well as the cistern feed, seems to point at some debris in the pipe before both of these devices.
Is there any safe way way of either rodding the pipe or injecting something that will affect any lime scale - or shall I give up & just get the pipe replaced?
Ta

 

[mark hurry]

Take the ballvalve off then turn on the valve,you should be able to judge if the flow rate is correct. Also check you have the right insert fitted in the ballvalve.
Hope this helps.

 

[Mikey456]

This is a long shot really. could be due to the hot pipe being below the cold pipe (Heat rises ofc), that causes bacteria build up etc as the cold pipe will always be fluctuating in temperature

 

[duffplumber]

Interesting, hadn't considered that. Methinks this is one for the pro's - we're embarking on a bit of major decorating/ tarting up prior to selling up & downsizing (kids gone, house too big etc) so get someone in & replace the pipe if need be.

This is a long shot really. could be due to the hot pipe being below the cold pipe (Heat rises ofc), that causes bacteria build up etc as the cold pipe will always be fluctuating in temperature

 

[AWheating]

cut the pipe bang on a hose pipe and flush. see if any crap comes out and what the flows like.