I\\\'ve had several problems with my central heating / hot water system since switching the CH back on when the cold weather started this year, most of which I\\\'ve solved but I\\\'m now stuck and would like some help...
To cut a long story short, I\\\'ve successfully replaced the programmer (from an old Randall dial one to a new electronic one) and replaced both the HW and CH two port motorised zone valves. After everything was complete and working properly (valves opening as called by programmer / thermostat, pump starting and boiler firing up as called for, radiators warming up etc), I bled all the valves on all the radiators - most of them had very little air in them apart from one of the upstairs radiators that took about 45 mins to bleed out. After completing this last radiator (everything was fine before this), the boiler then started to overheat and cut out very quickly (15 secs rather than the few minutes as normal) and on doing this the flow pipe coming out of it would distort along its length, make hammering and gurgling noises, and sound like something was being dragged through it on the inside. Additionally, the pump (Grundfos 15/50) heats up very quickly (very hot to the touch) and also appears to fail to switch off when it should.
I can\\\'t seem to get it working again, but I think something is either blocking the pipe out from the boiler somewhere along its length, or that bleeding ALL the air out from the upstairs radiator has caused a blockage somehow (the pipe that seems to be making the noise appears to go upstairs to the radiator, rather than to the pump / HW tank although this doesn\\\'t make sense to me..).
I\\\'d be very grateful for any help on this matter what with winter on its way! Cheers.
To cut a long story short, I\\\'ve successfully replaced the programmer (from an old Randall dial one to a new electronic one) and replaced both the HW and CH two port motorised zone valves. After everything was complete and working properly (valves opening as called by programmer / thermostat, pump starting and boiler firing up as called for, radiators warming up etc), I bled all the valves on all the radiators - most of them had very little air in them apart from one of the upstairs radiators that took about 45 mins to bleed out. After completing this last radiator (everything was fine before this), the boiler then started to overheat and cut out very quickly (15 secs rather than the few minutes as normal) and on doing this the flow pipe coming out of it would distort along its length, make hammering and gurgling noises, and sound like something was being dragged through it on the inside. Additionally, the pump (Grundfos 15/50) heats up very quickly (very hot to the touch) and also appears to fail to switch off when it should.
I can\\\'t seem to get it working again, but I think something is either blocking the pipe out from the boiler somewhere along its length, or that bleeding ALL the air out from the upstairs radiator has caused a blockage somehow (the pipe that seems to be making the noise appears to go upstairs to the radiator, rather than to the pump / HW tank although this doesn\\\'t make sense to me..).
I\\\'d be very grateful for any help on this matter what with winter on its way! Cheers.