Some of you may remember I had an issue with this last year. I got it working and it went the whole of last winter without any problems. Obviously during the summer I turned the termperature down low. Now, however, when the set temperature is above the room temp it calls for heat. However the boiler doesn't now fire up. The pump does, but not the boiler. I havn't changed anything since last winter, only removed it slightly to pait around it, but i've checked the cables and they're all in. The boiler still works for the water as it has done throughout the summer. I've got no way to test the heating. Any ideas? Thanks.