If I leave the tap on full it takes a bit of time and wastes a bit of water. If I leave it running not full it takes time, sometimes doesn't get hot at all.Good answers welcome.
To get hot water from a combi boiler you have to turn on the tap and then all the cold water already sitting in the pipe has to run out of the tap before the hot water comes through, you can alter the temperature of hot water that the boiler produces by setting it on the boiler itself
It's pretty quick if your outlet is right underneath the boiler, but it can't be instant unless there is a storage tank and the water gets heated before use. There should be a control to set the water temperature, and there may also be a switch which allows you to select hot water only, or hot water + heating. You may want to consider installing a single point gas/electric water heater nearer to your outlet, to save water money. I have this problem but the engineer said an additional heater wasn't worth the money it would save.
Some boilers have a small storage of hot water to shorten the delay. You usually have a switch to select or deselect this facility. Other than that no combi can supply instant hot water. Also if the heat exchanger is furred up with limescale it will take longer still.
Combi Boiler Instant Hot Water
This is normal for an ordinary combi boiler as it does not store the hot water. The water is heated as it passes through the boiler and takes time to reach the required temperature + how far the boiler is from the tap etc, as the cold water in the pipes has to come out first.. To get virtually instant hot water from a combi.you will need to install a hot water storage tank which is heated by the boiler,
