Hello.
Essentially I've got a problem where some radiators do not warm up properly, and others do get hot or hot"ish" at the top but they stay relatively cool at the bottom. I've read this could be due to sludge build up, or the system needed balancing. Naturally I wanted to try and balance it first before I drained the system and started taking rads off the walls, but I thought since I've now attempted to balance the system and apparently haven't made much of difference in doing so, I'd ask here to see if any pros can put forward some ideas before I go and get myself wet. But before that, maybe it's the pump? I dunno, what do you guys think?
Some info about the system; as far as I know it's a double pipe system in the entire house, there are 13 radiators, there's an expansion tank in the loft and we've got a hot water tank in the airing cupboard. The boiler's a Grant with a Riello gas-oil fired burner. It's an old system (though the boiler isn't), not controlled automatically by thermostats but rather controlled manually by me with two switches. One turns the boiler and the pump on (and there's a thermostat on the boiler that sets the temperature). The other switch controls a valve that either has the water pumping to the hot water tank or the rads.
When I tried balancing the system all I seemed to succeed in doing was making the rads colder than they were when the lockshield valves were fully open. I might also add that the only rad in the house that gets piping hot is the first one off the system which is upstairs, but all subsequent rads upstairs do not get particularly hot, some of the downstairs rads do however but they usually stay cold or slightly warm at the bottom (only one other downstairs seems to get relatively hot throughout the whole radiator).
There's two other things that seems to be a problem with the central heating. The first is when I have the rads turned off and having the boiler only feeding the hot water tank, a few of the rads still seem to warm up. The hot water tank also apparently take a lot longer to get to a nice temperature too. I presume this is because the hot water/radiator switcher valve or the electronic switch that controls it is worn out.
The second thing is more prominent, although I have solved it with a workaround. Air is getting into the system somewhere between the boiler and the first radiator (the first one that always heats up as mentioned above). I did look for leaks but could not find any. I ended up, as a workaround, fitting an automatic bleeder valve so I didn't have to keep on bleeding the rad. No, it didn't fix the underlying problem but it solved the problem of how often I had to keep bleeding the rad at least.
However I've read up on this (air getting into the system mysteriously) and the only thing that seems to correspond to not only air getting into the system but also the coldish radiators, is the water pump being on it's last legs. This pump is getting on a bit now. I'm not sure how old it is, it's quite possibly older than the boiler we've got now, but I do know that the power setting is currently on the max. I read somewhere that a failing or worn out pump can let air into the system. So, if that's true, would that likely be the source of the air? And would it also cause most of the rads to not warm up properly if it worn out?
Essentially I've got a problem where some radiators do not warm up properly, and others do get hot or hot"ish" at the top but they stay relatively cool at the bottom. I've read this could be due to sludge build up, or the system needed balancing. Naturally I wanted to try and balance it first before I drained the system and started taking rads off the walls, but I thought since I've now attempted to balance the system and apparently haven't made much of difference in doing so, I'd ask here to see if any pros can put forward some ideas before I go and get myself wet. But before that, maybe it's the pump? I dunno, what do you guys think?
Some info about the system; as far as I know it's a double pipe system in the entire house, there are 13 radiators, there's an expansion tank in the loft and we've got a hot water tank in the airing cupboard. The boiler's a Grant with a Riello gas-oil fired burner. It's an old system (though the boiler isn't), not controlled automatically by thermostats but rather controlled manually by me with two switches. One turns the boiler and the pump on (and there's a thermostat on the boiler that sets the temperature). The other switch controls a valve that either has the water pumping to the hot water tank or the rads.
When I tried balancing the system all I seemed to succeed in doing was making the rads colder than they were when the lockshield valves were fully open. I might also add that the only rad in the house that gets piping hot is the first one off the system which is upstairs, but all subsequent rads upstairs do not get particularly hot, some of the downstairs rads do however but they usually stay cold or slightly warm at the bottom (only one other downstairs seems to get relatively hot throughout the whole radiator).
There's two other things that seems to be a problem with the central heating. The first is when I have the rads turned off and having the boiler only feeding the hot water tank, a few of the rads still seem to warm up. The hot water tank also apparently take a lot longer to get to a nice temperature too. I presume this is because the hot water/radiator switcher valve or the electronic switch that controls it is worn out.
The second thing is more prominent, although I have solved it with a workaround. Air is getting into the system somewhere between the boiler and the first radiator (the first one that always heats up as mentioned above). I did look for leaks but could not find any. I ended up, as a workaround, fitting an automatic bleeder valve so I didn't have to keep on bleeding the rad. No, it didn't fix the underlying problem but it solved the problem of how often I had to keep bleeding the rad at least.
However I've read up on this (air getting into the system mysteriously) and the only thing that seems to correspond to not only air getting into the system but also the coldish radiators, is the water pump being on it's last legs. This pump is getting on a bit now. I'm not sure how old it is, it's quite possibly older than the boiler we've got now, but I do know that the power setting is currently on the max. I read somewhere that a failing or worn out pump can let air into the system. So, if that's true, would that likely be the source of the air? And would it also cause most of the rads to not warm up properly if it worn out?
