Woke up this morning to find no hot water and cold water only from the kitchen sink tap (which is the closest to where the main water pipe comes into the house). I have a combi boiler and the heating is still working. I've had it on full blast all day and have been placing a small heater in various places to try and thaw something out, but tonight still no water except from the sink cold water tap. Am I missing something - could it be something else or is it likely to be a frozen pipe? Is there anything else I can try?