Radiator flow problem in single radiator in 8mm microbore heating system

[gigabyte]

Hi there ... I have a single radiator in a 4 bedroom house that won't heat up. In fact, it never heated up even when the house was newly built, but somehow got neglected and forgotten about.

I know that:
a) the radiator is not blocked,
b) the valves are open (they are not thermostatically controlled),
c) the radiator will fill with hot water (from empty),
d) it will eventually go cold again once the heat has left the radiator.

This suggests to me that there is no flow throught the radiator during normal operation, and there's no difference even if I close the valves on all the other radiators.

To check the pipe leaving the radiator is not blocked, all I've been able to do is see it drain about a gallon of water when disconnected from the radiator. I think that if the pipe were totally blocked, then this flow would eventually stop. Instead, it flows continuously, although at a much slower rate than the flow at the hot end. Even at this slow rate, I would expect to feel some continuous heat in the radiator.

Note that this radiator could possibly be the furthest from the pump ...

Any tips on how to go about identifying the problem would be greatly appreciated. Thanks.

 

[Dotty]

Kinked pipe.

 

[Chalked]

Is it downstairs?
And does the pipework appear from the wall?
If so , it's probably on a drop from above. First try would be turn off the hot water at the programmer and turn on the heating, turn up the room thermostat to maximum. Then manually turn off every radiator including towel rails. This should push any air from the pipework. If this works and the radiator gets hot, leave it on for 10 minutes, then turn the other rads back on.

 

[Best]

If it doesn't work with all the other rads off method, then I would disconnect the valves from the radiator again and this time let the water flow for several minutes.
One thing that can happen rarely, but still very possible, is if the rad valve on the return is faulty inside, - if the brass 'washer' part inside valve was disconnected it would allow water out if you disconnect it from rad, but won't allow water going direction of return, back towards boiler. Worth considering. I had this happen on brand new quality valve.

 

[GasmanxxxR1]

It could be piped up wrong, ive seen rads piped from the flow on both sides instead of from the return on one. 30 year old house had this piped up when built

 

[gigabyte]

I think you may be right croppie. The thing is, all the pipes are kinked where they emerge from behind the plasterboard. On this particular rad, I did replace the kinked sections, but it did no good. I guess there could still be too much head loss on this particular loop ...

Also, Gasman's answer has also crossed my mind, but with tongue-and-groove chipboard flooring laid, I've not been able to locate the manifold! Also, with the microbore piping behing the plasterboard walls, I've not been able to easily trace the route of the return pipe.

To answer Chalked, yes, the rad is downstairs (in the same room as the boiler). I followed your tips, but still no joy.

Re: Best's comment, I'll have to take a closer look next chance I get.