Dave-G Posted December 29, 2022 Report Share Posted December 29, 2022 (edited) I asked the wife to fetch a radiator bleed key today - she bought two.... and at about 1/4" square they're both too big to fit the tiny valve stem square. Are there various size one's and if so how do we find the right size? Edited December 29, 2022 by Dave-G Quote Link to comment Share on other sites More sharing options...
TIGHTCHOKE Posted December 29, 2022 Report Share Posted December 29, 2022 Let the wife take the radiator to the Shops! Quote Link to comment Share on other sites More sharing options...
henry d Posted December 29, 2022 Report Share Posted December 29, 2022 (edited) Never known them to be different sizes? Are you sure it is not the outer diameter of the key that doesn't fit into the hole? The one's we have had in the last house and this have a slot to take a flat bladed screwdriver. Edited December 29, 2022 by henry d Quote Link to comment Share on other sites More sharing options...
B725 Posted December 29, 2022 Report Share Posted December 29, 2022 Just call in any plumber's merchant, buy a brass one it will last for year's Quote Link to comment Share on other sites More sharing options...
Rim Fire Posted December 29, 2022 Report Share Posted December 29, 2022 I always thought one fits all ?? Quote Link to comment Share on other sites More sharing options...
Dave-G Posted December 29, 2022 Author Report Share Posted December 29, 2022 Weird - I've just measured them with a vernier gauge that doesn't quite get deep enough to engage - but OK to make a good guess.... We have a mix of 4mm and 5mm square top valve stems and the key socket is 1/4" - likely classed as a 6mm. David Wilson home built late 1980's - likely a changeover to metric specs or some other 'modernisation' Quote Link to comment Share on other sites More sharing options...
Dave-G Posted December 29, 2022 Author Report Share Posted December 29, 2022 (edited) Whilst measuring the squares I was aware 'er indoors was scrabbling through several hiding tins and baskets for small stuff that needs to be stored out of sight... She finally found the one I had last used some years ago - it has a 5mm square socket that fits. The '4mm' one has a bit of taper on it. The 6mm keys came from wilko's It's looking like the recent update Combi boiler install might not be as good as it should be - or possibly just needs some running in to get air bubbles out of water if a Google result is correct. Edited December 29, 2022 by Dave-G Quote Link to comment Share on other sites More sharing options...
Dave-G Posted December 29, 2022 Author Report Share Posted December 29, 2022 (edited) OH joy! Bleeding a load of air out the radiators seems to have lost the internal? boiler pressure and it now doesn't heat water. A bit of a google suggests two flashing square symbols mean its apparently purging itself for 15 or so minutes after I followed re-pressurising to about 1.5 bar advice. Not loving the new tech that needs about a half minute of cold water before we get hot water - when it was installed, yet. Edited December 29, 2022 by Dave-G Quote Link to comment Share on other sites More sharing options...
Centrepin Posted December 29, 2022 Report Share Posted December 29, 2022 If you bleed the rads, you need to re pressurise the boiler afterwards. Normally a twist valve underneath dependant on boiler type. Quote Link to comment Share on other sites More sharing options...
Blackpowder Posted December 29, 2022 Report Share Posted December 29, 2022 24 minutes ago, Centrepin said: If you bleed the rads, you need to re pressurise the boiler afterwards. Normally a twist valve underneath dependant on boiler type. Quite correct if its a modern sealed system. Never came across anything than the one size of airvalve keys but I been retired for a year or two. Blackpowder Quote Link to comment Share on other sites More sharing options...
Dave-G Posted December 29, 2022 Author Report Share Posted December 29, 2022 Whew, its all back to normal now. Thanks very much all for the help given. It started when I heard some humming in bed this morning and after finding the inlet section of the bedroom rad was real hot but the rest of it wasn't. After poking around with the rad stat and knocking the rad to see if the hum stopped - it did. That prompted the bleeding when I got up. The installer had left a short length of flexipipe to connect from the mains in to another connection, first open the mains then the other till it pressurises. Its a Worcester Greenstar 2000 condensing combi. GR2300iW C unit. Quote Link to comment Share on other sites More sharing options...
old man Posted December 30, 2022 Report Share Posted December 30, 2022 I have 2 brass bleed keys, 2 different sizes too? 1 seems obsolete? Quote Link to comment Share on other sites More sharing options...
Gordon R Posted December 30, 2022 Report Share Posted December 30, 2022 I bought some tools a couple of weeks ago. Included was a bag of plumbers tools - Copex, Monument cutters etc. Inside were at least six types of radiator keys. Quote Link to comment Share on other sites More sharing options...
JohnfromUK Posted December 30, 2022 Report Share Posted December 30, 2022 I have just checked my bleed valves/keys. 5mm square most with a screwdriver slot as well. See typical example and vernier, and vernier in key. Quote Link to comment Share on other sites More sharing options...
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