DIY Doctor UK DIY Forums

I REPLACED ALL MY RADIATORS AT THE RATE OF APPROX ONE A WEEK DURING SUMMER DUE TO THE RADIATORS I HAD SPRINGING LEAKS. IT IS A BACK BOILER DOWNSTAIRS WITH A PUMP IN THE EMERSION CUPBOARD UPSTAIRS AND A HEADER TANK IN THE LOFT. AFTER REPLACING EACH ONE I CHECKED IT FOR LEAKS BLED THE RADIATOR, PUT THE SYSTEM ON AND EACH RADIATOR HEATED UP FINE AND UNIFORMLY ALL OVER.
NOW I HAVE PUT ALL THE RADS ON THEY ALL HAVE A COLD SPOT ON EVERYONE WHICH IS IN THE FORM OF AN ARCH SHAPE ABOUT 4-6 INCHES IN FROM EACH SIDE AND THE SAME DISTANCE FROM THE TOP OF EACH RAD. NO MATTER HOW MUCH BLEEDING I SEEM TO DO I CAN NOT GET THEM BETTER, ANY IDEAS ANYONE ?

I think this could be the heating pump on the boiler.

I have seen this before, last time the pump speed was too low and was turn up.

But if you have brought cheap radiators and they’re all from the same maker, it may be the design of them.