radiators cooler at the bottom

[cda3003]

Hi, I have recently had the system power flushed, but the problem has not gone the radiators are still cooler at the bottom. I think it may be balancing after investigating the web, however my engineer says it may be the thermostats on each radiator which are not working properly. One radiator is turned off and still gets warm. Please help dont want to replace all the thermostats if this is not the problem. Heeeeeeeeeeeelp

[The Builder]

............ opened a can of worms here cda :o(
Could be so many things ............... hot water rises to the top ............ rads cold at bottom, suggesting lack of circulation ..........
Try increasing the pump speed, or maybe it's stuck .............
Possibly, simply not enough hot water ........... turn boiler temp up?

I think I'll just gloss over the rad that heats up when it's turned off ........... either you've changed the Laws of Physics, or you've discovered an unlimited source of world energy lol

[AlBags]

Check balancing first! That is slow water flow causing that.

[jaydah]

is the feeder tank filled with water, presuming its CH.

[The Builder]

.................. yes, as Al says .................. balancing?

http://www.lovekin.net/radiator-balancing.html

[KARL]

I would be surprised if your radiators were not hotter at the top than at the bottom (unless they were only partly filled) although much depends on the size of the radiators in relation to the space they are expected to heat up (in the UK radiators are typically on the small side and also poorly located). It is for example quite normal after the heating cycle has stopped for a radiator to be reasonably warm at the top but the pipes and bottom of the thing being distinctly cool. Perhaps what you are meaning is that after a relatively short time on the radiators are still not warm from top to bottom. Again, where the temperature is usually below 21 degress (or more) this could be entirely normal and only after several hours of running and with everything at or above 21 degrees would they be clearly warm from top to bottom but even then they will under most circumstances still be noticeably warmer at the top than at the bottom. As for the radiator that warms up although turned off - you are presumably meaning that with a thermostatic valve turned "off" the radiator still warms up when the cycle is on. This can mean at least two things, the first being that the valve is in a cold zone so it remains open even though "off" (this has to do with the characteristics of these valves) or else (second) the valve simply is incorrectly calibrated. Most thermostatic valves can be calibrated to the user's specification/choice but apparently very few heating technicians know how to do that correctly. Just a small quibble: The people who deal with such things as heating are technicians, not engineers - the distinction is a little analogous with calling a nurse a surgeon, although uniquely in the UK much confusion surrounds the term "engineer". Elsewhere enginerers are seen in the same category as dentists, doctors, etc. but here an "engineer" connotes someone carrying a screwdriver and a pair of pliers in the pocket of an overall.

[AlBags]

Yes ..... Very interesting indeed.