Strange Radiator problem/Gravity return vlave???


Hi all
We have a glow-worm combi boiler in the kitchen, which is used to heat the water and supply the radiators when heating is required. Upstairs in the 2nd bedroom there is a cold water tank and hot water tank with an electric emersion heater.(never used). Today on returning home from work, the hot water has come on via the combi boiler(no heating on) but the radiators downstairs were all red hot, even though the timer was set to hot water only and the thermostat in the hallway was on minimum.
Any ideas???
have done a Google and the general consensus seems to be the gravity return valve???? If this is the culprit, where is it located and is it easily sorted..
Thanks for you help
Tony
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Yes. You do not have a combi.
If you have a gravity fed system then the gravity return valve may be to blame but I would expect upstairs rads to get hot not the downstairs rads. Double check to see what sort of boiler set up you have.
http://content.honeywell.com/uk/homes/systems.htm
HTH
Adam
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OK
Its looks like a C Plan Schematic from the info on the webpage but the radiators upstairs are stone cold when hot water only is on, only the downstairs radiators get hot starting from the one in the halway which is closer to the Glowworm
HTH
Tony
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I forgot the link did not give a gravity only set up. It will only be a C plan if you have the motorised valve. If you have no motorised valve it will be a traditional gravity system.
It may still be the gravity return valve, and depending upon your pipe layout it is possible that the downstairs rads heat up not the upstairs rads (the classic symptom).
If you can get uk.d-i-y on your newsgroup server ask there as it is a much busier group (with some real good experts in this field)
Adam
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