im getting hot water but only when tap in bathroom is turn right down turn it full on and the water runs almost cold

glen, January 2010

When the tap is marginally open, the flow of water is low enough that the boiler has time to heat the water. When the tap is fully open, the flow of water is too high, thus the boiler hasn't enough time to heat the water. Modern boilers overcome this by limiting the flow of water until a preset temperature, usually set by the user, has been reached.

Regards.

Rich UK, January 2010