kitchen hot water issue

[dugald]

Hi everyone,hope you can help. My hot water in the kitchen mixer tap takes an age to come through. The rest of the taps in the house are fine and don't take long at all.
We run on a oil fired combi boiler and the flow to all the taps including the kitchen sink is very good. When the water does get through it is fine, just takes a long time to come through the pipes.
Other info: there are two isolation taps under the sink in the cupboard which turn off the water supply to the rest of the house. One for the hot water, one for the cold.
It also seems to come through quicker if on full, sometimes the hot doesn't come through at all if the tap is only slightly on.
Hope this makes sense and someone can help. Seems daft to call a plumber out to look at a tap that works fine. (All be it a little tardy)
Thanks, dugald

 

[Hugh Jaleak]

First thought would be how long is the run of pipework from the boiler to the sink, and also it's size. If some 22mm has been left in from tank feed days, then this can leave a large amount of cold water that needs to be run off before any hot will reach the tap.

 

[TCCHeating]

Agree with above, but also it could be a faulty mixer tap not closing the cold off fully when set to hot. If you can isolate the cold supply to the tap leaving the hot supply open then you can test to see if you get hot water quicker. You could also try turning off the cold water inlet to your combi, if you then still get water flowing through the tap when set to hot then you definately have a prob with cold water passing into the hot pipe.

 

[jeff the gasman]

If it's a long pipe run why don't you fit a small unvented under sink water heater. Instant hot water and efficient.
Jeff

 

[dugald]

Thanks everyone will try turning off the cold water and see what happens. Pipe length is not much longer than any other in the house. Cheer for now.