Tempest hot water indirect unvented cylinder confusion

[Graham J W]

Hi all,

Recently moved into a refurbished house and having issues with hot water delivery to "some" taps ?.

New 2023 installation of heating system and hot water. Heating fine via Vaillant ecoTech plus 630 coupled to a Tempest indirect 300L cylinder. Cylinder gets hot as required but :
Kitchen tap (nearest to cylinder in attached garage) takes ages before hot water comes through but the ground floor shower and sink ( in the next room) get hot water very quickly. Upstairs bathroom sink again takes ages for hot water to come through but the bath and the shower in the same room again get hot water quickly ?
Mains water pressure good so the cylinder should be pressurised ok.

Any thoughts appreciated

 

[Johntheo5]

It's possible Xover from cold to hot, is the (balanced) cold supply taken off the unvented cylinder valve set like below??.

 

[Graham J W]

Good morning Johntheo5.
Thank you for replying. A valve such as that is installed and with the mains connected as your picture. There looks to be several connections from the outgoing side with one of them going to the cylinder. It has the expected 3bar marking on the valve which I believe is pre set by Telford cylinders. ( cold main inlet control group).

 

[Johntheo5]

Can you shut off the mains cold into the unvented cylinder, should be a lever valve upstream of that valve group and then confirm that there is no cold water coming from any of the taps.
Are the (slow) kitchen and upstairs bathroom sink taps one lever mixers or are the hot and cold taps separate and then mixing when they leave the spouts?