I had a combi boiler fitted 12 months ago. Hot water is fine. downstairs radiators are fine but all upstairs are cold. I have turned of the heating and bled all the radiators, small amount of air downstairs. Virtually no air came out of the upstairs rads and no water is coming out. What do I try next?? Will draining the whole system and refilling help???
It sound as if the system needs balancing, as has been mentioned further down ( in think there was even a link)... Remember the water will alway tend to take easiest route. So, the hotter rads have better (more) flow through them. Restricting the flow to these will encourage more flow (of hot water) though to the colder rads.
You are saying no water is coming out of the bleed valves on the radiators. I am no expert but it sounds to me like the system needs refilling/re-pressurising via the filling loop on the boiler and then bleed the radiators upstairs. If the air stops coming out before water appears, you will need to repressurise again and carry on until you have got all the air out of the system. DON'T Forget to tighten the bleed screw(s) if you need to refill halfway through! When all the air is out repressurise the system to the correct bar rating, usually the plumber sets a red pointer on the dial, but look in your manual if necessary.
HTH
John
so before I go as far as emptying the system and refilling try turning off downstairs rads and see if that pushes the flow upstairs ??
Yes. Let us know how you get on.
If no water's coming out then your system pressure is too low.
Combi boilers are (almost always) pressurised sealed systems. There will be a "filling loop" which is a pair of taps which allow you to use mains pressure water to fill the system using the pressure gauge on the boiler to decide when to stop. There's usually a flexi-hose between the two taps. Do that and bleed the system again, repressurising again if needed. Then see what happens.
Sorted!!! Eventually. We read through the handbook which seemed designed for the fitter rather than the layman problem solver, got to the part that mentions pressure drop and the book says " teller the customer what to do in the event of a pressure drop". If I was told I would have written it down and put it with all the other paper work so I wasn't told. Eventually we worked out that the bit of plastic the plumber had left was a key and it then took a while to figure out where to put it. Radiators off turned key and filled the system. Removed a mass of air from the upstairs rads and then hey presto I have heat. Thanks for all who offered help. the pressured had dropped down to virtually zero.
You're lucky you didn't have the usual filling loop, they are supposed to remove it when they finish.
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