We had the boiler serviced in September, everything was working fine, nothing needed fixing. We don't use much hot water and hadn't had the heating on since last winter, but had no problems when it was all checked. We then went on holiday and turned everything off. On returning we put the heating on, but found we had no hot water. Radiators are fine and if we turn the hot water on, it heats the radiators well, but we have no hot water. We get a little cold, followed by a few seconds of tepid water and then it runs cold again (but not quite as cold as the cold tap). The pipes around the hot water tank feel hot and the thermostat hasn't been turned down at all. We have had the hot water turned on for a full day in the hope of heating the whole tank, but to no avail. Any thoughts would be appreciated please. It's not a combi boiler as far as I know, just a gas boiler that is about 8/9 years old.