Erratic kitchen mixer tap (hot side)

[seadog]

Hi, it's my first post!
My hot side of the kitchen sink mixer tap works okay sometimes and not others, it is a system fed from from a cold storage water storage tank in the loft down through the hot tank, the water eventually comes through after a few minutes. I have renewed the tap washer, thinking that it was damaged but it only had a deep cut. When the water comes through the flow is good and doesn't look as if there might be rust restricting it. I have checked under the sink at the inlet pipes (there are in line maintenance valves) and have been under the floor and can't see any leaks. It has been like this for 3 years since having the kitchen done, the galvanised steel cold water storage tank which was in poor condition has just been replaced with a new plastic one. Any ideas?

 

[Slugbabydotcom]

You will probably find that your sink tap has a non return valve and isnt meant for systems with less than say a 5 metre head.
From the loft to your sink will probably be a borderline case.
Where to go from here:-
Get rid of the NRV .....Cheapest easiest option so long as it isnt built in to the tap.
Change the taps ......Next best
Raise your header tank..... Might not work if you cant get the tank high enough
Fit an unvented cylinder...... Very expensive but well worth the expense
Fit a combi.... More expensive and not as good as unvented cylinder