glowworm ultimate cycling

spinningsheep

Hi im posting on behalf of my parents. They have a glowworm ultimate BF running 9 rads and a towel rail. The system has no room stat or hot water tank stat so they run the boiler on the lowest possible setting otherwise the hot water is unusably hot.the problem is recently the radiators only seem to get luke warm and the boiler itself on the wall in the kitchen is getting very very hot, will run for a max of about 1 minute then cuts out, then the cycle repeats. So the house does warm up but takes an age. Pump is running g and makes no excessive noise. Any ideas?

Pincher

Arterial thrombosis.