That's right,stop it hold for a few seconds then let it go for a few seconds and repeat the action as many times as you like,but four or five times should do it. The action is a lot more aggressive than just turning the pump on and off.Hope that helps.
So it worked. I've now got 5 out of 6 rads hot and the boiler is firing normally and not shutting down for long periods. Amazing. Just have one rad which is the one last on the loop in the bathroom which I can't get hot. It's hot to the flow valve and if I put my hand on the valve I can feel the hot water pulsing in and out but it won't get as far as the rad. Like this with all other rads off too just can't seem to get it hot. Thank you so much for all the help so far couldn't have got this far without it.
Good call p'boy . Mr Fellows, are all the rad valves still fully open? If so, start to turn down/off the ones which are getting hot so as to get all the flow to the remaining miscreants. If fact, if a rad is getting nicely hot and there is definitely no air in it (try one last bleed, but don't forget to 'bleed' with the pump OFF!), then I'd be tempted to isolate that rad from the system by shutting both ends off fully. Then concentrate on eliminating the rest...
Only open a quarter of a turn on most of them and getting a good flow through just can't get it to flow to the last rad. Well it flows as far as the flow pipe but it's like there's not enough oomph to push the water through the rad. Confused.
What kind of bleed do you have on the rad that won't heat up,is it a half inch one that you can remove??
Yes I can get the bleed valve out of the radiator if u mean the one at the top. But is full of water though so no air or do u think that would drag the water through.
OK.What you need to do is turn boiler off,then shut both rad valves to that rad and remove bleed.Right you will need a rad valve tail that you can screw into where the bleed was removed and then attach a hose to this. OK what you do is open one rad fully open and the water will flow fullbore out of the hose,let it run for 30 secs and then shut that valve and then repeat on the other valve,that should do the trick.
Thanks so much that did the trick. Massive massive thanks to all who have posted this week it's been a massive help and I've certainly learned a lot lol. All rads now working and have a very happy wife.
Hi I am a newby on here but what i did when i had this problem on one of my installs was (I can hear the sharp intakes of breath as i write this) due to poor acces to the F &E tank i cut a full flow valve into the discharge side(heating fill) and connected a hose to the pipe and the other end on to the outside tap I then connected a 3/4 hose onto the vent to a drain , in this case the toilet then turned the water on and blasted the air from the system.All radiators were closed at first and then i went round each rad individually. i left the hose running for about 5 mins each(overkill i know). turned itt off ,reconnected the pipework to the fe and bled system as normal perfect. wished I had done it at the outset and it would have saved me 6 hours chasing airlocks on a microbore system. I know you shouldnt have a valve on F & E outlets , but needs must and it worked a treat
Plumberboy what a trick ! i have never heard of this but I am sure going to remember it. its a hell of a lot easier than what i have done . GIVE THAT MAN A MEDAL cheers
Very interesting thread, but nobody has mentioned the need to open any motorized valves by locking the lever in the Man position. If this isn't done the water cannot circulate properly to fill the system.