Monobloc tap running slow on cold only

[Paul205]

Hi all,

In my upstairs bathroom I have a Crosswater Modest Monobloc tap which is suitable for low pressure use.

The cold water comes directly from the Cold Water tank mounted 2m above in the loft and the hot water comes directly from the Hot Water Cylinder in the adjacent airing cupboard.

The flow rate of water in hot water mode is good but when the tap is pushed to the cold water only mode the flow rate is perhaps 200mL a minute!

The tap has been installed for circa 5 years and has got progressively worse.

I would appreciate any thoughts on what maybe causing this.

Many thanks




Paul

 

[terryplumb]

Sounds like the cold valve in your tap is iffy. Is it a screw down / up type tap head ,or is it a 1/4 turn lever type ?

 

[Paul205]

its a quarter turn tap

 

[Paul205]

https://www.crosswater.co.uk/product/taps-tap-collections-modest/modest-basin-monobloc-mo110dnc/

 

[terryplumb]

OK that has a cartridge valve. You could take lever off. Unscrew valve and examine to see if any debris / limescale / gunge is present. Turn off hot and cold supplies to tap before you do ,and you will need a rather large adjustable spanner to undo the big nut. Maybe a set of Allen keys too. Replacement cartridges are available . normally I would just advise to change the tap ,but as yours is over ,200 quid its worth the effort to repair.

 

[Paul205]

I assume an air bubble in the system would not contribute to this fault

 

[terryplumb]

If the problem suddenly appeared ,after loft tank ran dry maybe. But progressively over 5 years is no air lock. Either tap as said , or a restriction in pipework a lesser possibility. to establish supply is OK , look at cold pipe under the tap ,you may have a flexible hose going from an isolator to the tap. If so its easy to verify supply is OK. Post a pic so can advise further

 

[Paul205]

thanks guys, Well I took the cartridge out of the tap (which didnt come out as a single cartridge basically the cartridge came apart). The cartridge looked OK however I tested the water with the cartridge out and the rate of flow from the hot was signifiantly quicker than the cold. This suggests to me possible a supply fault?

 

[terryplumb]

What's the set up below the tap ?

 

[Paul205]

into the tap are hot and cold flexi pipes (supplied with the tap). I am beginnning to think that perhaps the rubber tube in the cold flexi may have got twisted?

 

[terryplumb]

If you disconnect cold flexi then test the flow from the pipework. If that's OK then unscrew flexi from the tap body and check its clear ,especially at tap end where it becomes very small Internal diameter.