I have just moved into a late 1990s new-build house with a small bore (about 1/2" OD pipes) gas fired boiler central heating system. All the normal radiators get hot but two of the three towel heater/radiators don't get hot and the pipes feeding them are cool to the touch even after the boiler has been firing for several hours.
The pipes do not enter at the same end of each radiator as I understand is normal for microbore systems - one pipe goes to one end and one to the other end.
The house was unoccupied for about 30 days between the previous owner leaving and my moving in. During this period I did not adjust any thermostat valves and set the CH room thermostat to 15C to keep the house warm to prevent mould. The previous owner says they were working when he left and I don't doubt him.
When I moved in after the 30 days I set the CH to much hotter. The two towel heater/radiators upstairs don't get the slightest bit hot even after the CH has been on for several hours. The thermostat valves are set to " III " so the valves should be open. The other radiators, including a thermostatically controlled towel heater/radiator downstairs all get hot.
I tried bleeding the non-heating radiators. "Clean water" appeared immediately suggesting no air in them.
I cannot understand it.
Am I correct in assuming there is a distribution manifold somewhere and flow and return pipes star off it to each radiator?
I seems like a pipe or valve is blocked but it would need two blockages, one for each radiator, and that seems too much of a coincidence.
Where is the distribution manifold likely to be and is there likely to be an access hatch for it?
Any suggestions for possible causes and/or fixes will be greatly appreciated before I call in a plumber.
Edit.
I saw this comment from searching : "apart from the two towel radiators which are connected to the hot water loop". Could it be caused because I haven't been using much hot water? The showers have been used 3 times in two days and is the only real hot water usage.
The pipes do not enter at the same end of each radiator as I understand is normal for microbore systems - one pipe goes to one end and one to the other end.
The house was unoccupied for about 30 days between the previous owner leaving and my moving in. During this period I did not adjust any thermostat valves and set the CH room thermostat to 15C to keep the house warm to prevent mould. The previous owner says they were working when he left and I don't doubt him.
When I moved in after the 30 days I set the CH to much hotter. The two towel heater/radiators upstairs don't get the slightest bit hot even after the CH has been on for several hours. The thermostat valves are set to " III " so the valves should be open. The other radiators, including a thermostatically controlled towel heater/radiator downstairs all get hot.
I tried bleeding the non-heating radiators. "Clean water" appeared immediately suggesting no air in them.
I cannot understand it.
Am I correct in assuming there is a distribution manifold somewhere and flow and return pipes star off it to each radiator?
I seems like a pipe or valve is blocked but it would need two blockages, one for each radiator, and that seems too much of a coincidence.
Where is the distribution manifold likely to be and is there likely to be an access hatch for it?
Any suggestions for possible causes and/or fixes will be greatly appreciated before I call in a plumber.
Edit.
I saw this comment from searching : "apart from the two towel radiators which are connected to the hot water loop". Could it be caused because I haven't been using much hot water? The showers have been used 3 times in two days and is the only real hot water usage.
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