Most of our rads never get hot at the bottom, so we took the 2 worst ones off on Sunday and flushed them out in the garden with a hosepipe until clean. They had some nasty thick black gunge at the bottom. We connected the rads back up and went round to bleed all the rads in case any air had got into the system . The heating came on later in the afternoon, only all radiators now will only go lukewarm.
Checking the boiler, the boiler will not stay lit for longer than about a minute at a time before switching its flame off before trying to fire up again in about 10 minutes. The pump remains on, as the room temp has not yet been reached so will not power off as it thinks the system is still working. You can feel the cold water start to circulate through the rads when the boiler fires off and the pump remains on. The pump did seem to be more noisy than normal as if it may be struggling.
We left it all switched off over night and drained the whole system and flushed it all out on Monday thinking that some silt we've disturbed may be causing a slight blockage. We drained every downstairs rad and then flushed it all through until the water ran clear on all of them. That took some time! Some of them were quite bad with the black silt. We even cleaned the header tank in the loft, which was quite dirty too.
We then filled the system back up, waited 10 minutes for any air to settle and bled all the downstairs rads, then the upstairs rads. Left it to settle for a while again before turning the boiler back on. It lit fine, but again, would not fire for longer than 1 minute before switching itself off. The pump remains on – judging by the sound. However, this time, not even the nearest rad to the boiler gets even remotely warm, which would suggest nothing is getting circulated.
We can only assume that the boiler is overheating due to some silt debris getting into a main part and restricting the circulation of water, or maybe air somewhere in the boiler or pump that we can’t get out. When the flame goes out now, there is a faint noise from the boiler, which we think sounds like it's hissing or boiling inside and therefore overheating.
We have a Stelrad Ideal Classic NF 80 boiler. It’s not a combi boiler. It’s open vented with a header tank in the loft. It’s a British Gas Grundfos Multihead G Class H (P/N:59506180) pump set to the max setting (3). There’s 15 rads in the house, none particularly big.
Don’t believe this should make any difference, but we put 2 litres of Sentinel X400 into the system 3 weeks ago to start loosening any sludge, knowing that we would be flushing the system out shortly. Some of the cold spots on rads had improved, but it was still evident the rads were in a bad state internally.
We’ve lived in our house for 6 months so don’t know the full history of the heating system, although the house is only about 10 years old.
1] Is there a way to bleed the boiler or pump to make sure we haven’t got trapped air in either of them?
2] If there’s muck got into the boiler or pump, is there any way of flushing them out?
3] a couple of friends have said it sounds like when their thermocouple needed replacing, but would flushing a system out break an electrical part?
4] anything we’ve not thought about that we could try? It seems too coincidental that a part has broken just from flushing the system, maybe there’s some valve we’re not aware of that needs tweaking?
Checking the boiler, the boiler will not stay lit for longer than about a minute at a time before switching its flame off before trying to fire up again in about 10 minutes. The pump remains on, as the room temp has not yet been reached so will not power off as it thinks the system is still working. You can feel the cold water start to circulate through the rads when the boiler fires off and the pump remains on. The pump did seem to be more noisy than normal as if it may be struggling.
We left it all switched off over night and drained the whole system and flushed it all out on Monday thinking that some silt we've disturbed may be causing a slight blockage. We drained every downstairs rad and then flushed it all through until the water ran clear on all of them. That took some time! Some of them were quite bad with the black silt. We even cleaned the header tank in the loft, which was quite dirty too.
We then filled the system back up, waited 10 minutes for any air to settle and bled all the downstairs rads, then the upstairs rads. Left it to settle for a while again before turning the boiler back on. It lit fine, but again, would not fire for longer than 1 minute before switching itself off. The pump remains on – judging by the sound. However, this time, not even the nearest rad to the boiler gets even remotely warm, which would suggest nothing is getting circulated.
We can only assume that the boiler is overheating due to some silt debris getting into a main part and restricting the circulation of water, or maybe air somewhere in the boiler or pump that we can’t get out. When the flame goes out now, there is a faint noise from the boiler, which we think sounds like it's hissing or boiling inside and therefore overheating.
We have a Stelrad Ideal Classic NF 80 boiler. It’s not a combi boiler. It’s open vented with a header tank in the loft. It’s a British Gas Grundfos Multihead G Class H (P/N:59506180) pump set to the max setting (3). There’s 15 rads in the house, none particularly big.
Don’t believe this should make any difference, but we put 2 litres of Sentinel X400 into the system 3 weeks ago to start loosening any sludge, knowing that we would be flushing the system out shortly. Some of the cold spots on rads had improved, but it was still evident the rads were in a bad state internally.
We’ve lived in our house for 6 months so don’t know the full history of the heating system, although the house is only about 10 years old.
1] Is there a way to bleed the boiler or pump to make sure we haven’t got trapped air in either of them?
2] If there’s muck got into the boiler or pump, is there any way of flushing them out?
3] a couple of friends have said it sounds like when their thermocouple needed replacing, but would flushing a system out break an electrical part?
4] anything we’ve not thought about that we could try? It seems too coincidental that a part has broken just from flushing the system, maybe there’s some valve we’re not aware of that needs tweaking?
