Replacing old designs of taps with new

[DIY10291]

OK , the taps you have linked to, if it was me making the determination, unfortunately are unsuitable.

If you are on a 2 level house with standard height ceilings (~2m) with the cold cistern (CWSC) in the attic ~ 1>2m above the level of the bath taps then you have ~ 0.1>0.2bar pressure in the bathroom with ~ 0.4bar in the kitchen.

The bath mixer tap linked to has a ceramic cartridge and will perform poorly with gravity Hot water judging by the quoted figures
The Sink mixer isn't a dual flow tap therefore there could be issues with the mains cold interfering with the HW supply, that and the min flow figure would suggest poor performance
The basin mixer tap, as was suggested by @HERTS P&D, isn't suitable for the basin you have. You would usually have to change the basin to suit a monobloc tap, that being said, again the choice is a ceramic cartridge type tap that will struggle with a gravity supply.

I would also be surprised if the basin cold was mains fed as usually in these cases all the bathroom water would be supplied from the attic cistern rather than a mains supply run to the bathroom just to supply the basin.

If you search for dual flow mixer taps you will see what is available.

Very interesting. Thanks for your patience.

Yes, cold tank in the attic, hot tank on the first floor, kitchen and bathroom on ground. Standard-ish ceilings.

The bath tap currently has two ceramic quarter cartridges - but the new tap would perform worse? That's a shame, I thought they looked pretty similar.
Kitchen sink mixer - I see, about the dual flow. Are most modern kitchen mixers single flow? There don't seem to be many listed as dual flow, and it's not a filter for the Screwfix webpages etc.
Basin mixer tap - is it (just?) about the size of the hole? And again, I am currently using two quarter turn ceramic glands and the flow is fine, but is the flow worse with a ceramic mixer?

The joys of an old house... Thanks again.

 

[Madrab]

The bath tap currently has two ceramic quarter cartridges - but the new tap would perform worse?

It doesn't have cartridges, it has 1/4 turn ceramic valves, they are different. Cartridges are typically more restrictive to flow when the pressure is low the the valves aren't as bad and those 1/4 turn valves are designed to work better with low pressure.

Don't believe everything on the NET -

These are 1/4 turn ceramic valves not ....................................... This is a ceramic mixer cartridge
cartridges, these would be in the old bath tap ....................... that would be in the new one

-----------------

I am sure you can see the difference and which one would probably be more restrictive with low pressure

Most mains pressure mixer taps are single flow as the H& C supplies are usually mains pressure balanced so mixing in the body of the tap doesn't present any issues.

The basin tap would suffer the same issue as the sink mixer as the tap components are similar in their differences , it's all to do with the low pressure in the gravity system you have.

 

[Harry Bloomfield]

These are 1/4 turn ceramic valves not ....................................... This is a ceramic mixer cartridge
cartridges, these would be in the old bath tap ....................... that would be in the new one

So you are saying there are some 1/4 turn ceramics, which are suitable for an open vented HW system?

 

[Madrab]

1/4 turn ceramics

1/4 turn ceramic valves are suitable for low pressure, their flow will not be up there with old school compression taps but they're a lot more free flowing and less restrictive than mixer cartridges.

It also comes down to how the tap is designed internally, low pressure taps invariably have larger and smoother waterways and the inlets tend to use M12 copper tails if it's a mixer. That being said I have found that they never work as effectively as 15/22mm fed individual taps, on a low pressure system.