i have now topped it up to 1 bar but there is still no change
grundfos selectric 15/50 pump noise
- Thread starter jamie488
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there is no air bleed directly above the pump. The pipe runs into the attic. Is it the case that there could be a bleed valve up there?
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i have checked in the loft and opened all the bleeding valves that i could find. A small bit of air came out of one of them then water flowed. There were two valves that released no water or air that seemed to be dry. I looked in the loft for valves above the boiler but there were none.
these are probably blocked and restricting the circulation, you need to remove the caps (one at a time) and cclean out the vent with a pin or something. have some towels ready and keep the cap handy to pop back on as water may come out quite quickly and suddenly.
there is no blockages in the bleeding valves in the attic. I took the caps off the ones that were dry. They had black plastic covers over the top once the metal cap was removed. I took the plastic top off and water came shooting out. I managed to put the cap back on but it does not seem to be flush anymore as i could not get the plastic stopper on as well. I have emptied the pressure from the expansion tank to stop the water leaking out anymore. I think i will have to call a plumber tomorrow as i dont want to touch any other valves.
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think the 2 of u aare confusing each othe. if you have a header tank then ur systems pressure is comming from the 'head' of water above. the water naturally takes the easiest route which is down creating ur sys pressure. the other guy right in what he says bout the auto air vent is i think assuming it is a 'sealed' system in what case u would have a auto air vent. without knowing ur sys i could confuse u even further but i take it becuse u said u tried to bleed the pump of air you have acces to it?! therefore not a combi! Turn the t/stat on ur boile right down to 0, but keep all external sources (eg.programmer, c/h t/stat etc calling for heat. this will make the pump run alone without running the risk of itoverheating whilst airlocked up! on the flat side of ur pump there will be a little dial with 3 speed settings on it, u wiil be able to hear the pump running let it run 1st for least 4/5 mins @ speed3, then turn thelitte arm on the dial in between speed 2nd 3. the pump in this position with u controlling it will stop the piump runnig,. this will take a few attempt till u get the feel of it. listen to sound of pump running and sound as u approach speed 2. u will see what i mean. repeat stopping pump then letting run 4/5 mins several times. when it starts to work u will clearly be able to hear the air bubbling back up the expansion pipe! honestly in an open sys propperly locked, this is the only way. may take a wee while but it all the good things do! Beanie(B.G. Engineer)
Surely not?
Yeah, turning the boiler stat to zero will stop the boiler firing up whilst allowing the rest of the system to run, but that alone won't stop the pump from overheating if it is airlocked.
The majority of the pumps run wet bearings, that is, they are lubricated by the water flowing through the pump. Running the pump whilst airlocked and dry will overheat it and knacker it.
OP: You mentioned removing the bleed screw from the pump in order to check that the shaft was rotating. When you did this did you get water come up? There should be a continuous little stream, if you don't get this then there is a good chance the pump is airlocked. You can try leaving the cap off for a while, (whilst you watch it with a towel), to see if you can start to get a water flow.
If you can get the water coming out the bleed screw then it is worth slowly rotating the shaft a couple of times (make sure the power is off first, you don't want the pump starting mid turn!), and then you will know that the pump has flooded. Refit the bleed screw and then do the pump pulsing as described above.
If you can't get the pump to flood then the next step I would take would be closing the isolation valves on either side, and removing the pump, then opening the isolation valves VERY carefully & SLOWLY & SLIGHTY with towels and bucket on standby to check whether there is water in the pipe either side of the pump. Of course you may want to get a plumber to do this if you are not comfortable doing it yourself.
An airlocked pump can be a swine, but it's not the end of the world
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