What is the cause of a radiator which is cool at the bottom, but hot at the top? (I understand that if the reverse were true, the radiator would require bleeding.)
Thanks, Edward.
- posted
17 years ago
Radiator anomaly
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- posted
17 years ago
Sludge,
Andy
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- posted
17 years ago
Likely it's full of sludge.
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17 years ago
If the outlet pipe is hot, it's sludge. If the outlet pipe is cold, there's inadequate flow (system probably needs balancing, or pipework is blocked).
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17 years ago
Or anything restricting flow.
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17 years ago
When was the system flushed? Best to do it this week while the weather is warm
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- posted
17 years ago
wrote
This is common if the radiator has been "throttled down", either to push heat to other radiators, or because the room has a larger rad than is really necessary. Check the valves at both ends. Close the handwheel valve counting the number of turns to close (or note the setting if you have a thermostatic valve). At the lockshield end, remove the cap (may be a small securing screw to take out first). Using a suitable spanner on the exposed shaft square, close the valve, again counting the number of turns required. Now fully open both valves and run the heating for a while. If other rads on the same circuit get hot over entire surface and this one still has cold(ish) bottom half, then yes the chances are you've got a sludged up rad or feed pipes. If it gets hot all over, then it's a balancing thing and the rad has been deliberately throttled for the reasons noted above. If you are happy with the way the system was behaving previously and the above test reveals no sludge, fully close both valves and re-open to the positions noted earlier. Then walk away happy. Otherwise, best to remove rad (method has been covered frequently - google) and check the sludge theory by flushing and catching/straining discharge. If there are serious sludge deposits and not just a bit of black water in the final drips, then look for an Ed Sirrett email in this group and read all of his FAQs to learn about the maintenance of heating systems.
HTH
Phil