What is wrong? Please HELP!!

Discussion in 'Plumbers' Talk' started by nfollows82, Oct 14, 2014.

  1. nfollows82

    nfollows82 Member

    Might be a stupid question, but if I do the drain with the valves shut, will that still drain the rads?

    With us now looking at circulation, could this actually be time for a replacement pump?

    I know I've read previously that hot upstairs/cold downstairs points to the pump not working, and especially when I can't get any circulation downstairs with the upstairs rads closed.

    Now, with the pump replacement I'm sure I've read that it's possible to just replace the front bit of the pump rather than removing the whole thing from the pipework and refitting the new one..........how true is that?
     
  2. If you drain down the system with both rad valves on each rad fully shut, then whatever water is in the rads should stay in the rads.That keeps them out of the equation for the moment.

    What I'm suggesting is to try and limit the purging (for that is what it's called...) to the basic flow and return pipes only. Mind you, the flow and return do need to be looped at the ends or else nothing will flow! If they don't have a by-pass loop at the end, then you'll need to open one end rad instead. Do this only when the system has been fully refilled - open the bleed nipple, and hopefully you'll hear air when you open the valves. Open the valves on this one rad fully.

    By back-filling dead slowly, any air bubble sitting in a high spot in a pipe might be tempted to be teased along and out rather than being 'locked' in there by water coming at is from both sides (pure guesswork - that might not work...)

    As for your pump - when you turn it on does it go whoooosh?! I guess it is possible for the pump vanes to be worn or corroded? I dunno. Does it have isolating valves on either side?
     
  3. plumberboy

    plumberboy Well-Known Member

    If the pump runs OK just try the pump jam trick it never fails when needed,I used it on a friend of mines system he had spent all day messing around trying to get circulation I went round done the pump jam trick and system was running 5 mins later.;)
     
  4. tom.plum

    tom.plum Screwfix Select

    I've never heard of the pump jam trick before now PB, how does that free an air lock ?:confused:
     
  5. plumberboy

    plumberboy Well-Known Member

    Hi Tom.Is it wet in Wigan today.:(
    An old plumber showed me it years ago, I'm guessing because the pump has a capacitor and you jam and release a few times that sudden woosh of circulation seems to move the air lock,I must say seems to work well but only if you have no circulation going on at all.
    That's all I know about how it works.;)
     
  6. Try it, Mr Fellows - try it try it try it!

    I can see it having a very percussive effect on the water - when a pump just starts up normally with lecccy power, it is probably a wee bit 'soft start'. By doing what p'boy suggests, it's a very on-off effect, and that might be enough to push - shock - the air bubble along.
     
  7. tom.plum

    tom.plum Screwfix Select

    I'll try it next time i'm stuggling with an air lock and report back, everydays a skool day, and if it works i'll make a video and give you the credit PB,;)
     
  8. plumberboy

    plumberboy Well-Known Member

    Cheers Tom.You're right everyday is a skool day the more I read DA's posts each day my grammer gets just a little bit better,and I do mean a little bit.:)
     
    Last edited: Oct 15, 2014
  9. tom.plum

    tom.plum Screwfix Select

    yea that Mr Devs has helped me a lot in the last 10 years, he's a good skool teecher he learned me that its you're right, not your right , and lots of other stuff too (not to) that i never knew (not new), ;)
     
  10. plumberboy

    plumberboy Well-Known Member

    Ha Ha!!! See I just had to edit my post,I'll get there one day Tom.:(:oops:
     
  11. tom.plum

    tom.plum Screwfix Select

    we are what we are PB, we're plumbers and no-one with a decent education wants to be a plumber and we would never want their life iether, we can't write proper,they can't plumb proper, and this forum helps us to help them,and them to help us, nowt wrong with a bit of trading off hey, :)
     
  12. Glad its Friday

    Glad its Friday Active Member

    Air locks aren't usually this hard to shift.
    I reckon that when you first drained down, you dragged a load of sh!t down from the F&E. When we have to drain older systems, we always check how much crud there is in the F&E first and siphon it all out before draining down.
    So rather than an air lock, you've got a blockage (maybe).
    Try switching the pump from low to high speed and back again quickly. This will create a kind of surge in your pipework (lot less stressful than jamming a screwdriver into the pump!).
    Otherwise, drain down and start replacing pipework round the pump and valve area.
    One other thing to check is the gate valves. Sometimes they shear off inside when you open them. So you think you've opened them up but actually they are still shut. Check the one on the CH flow.
     
    Jitender likes this.
  13. plumberboy

    plumberboy Well-Known Member

    Very very true Tom.;)
     
  14. nfollows82

    nfollows82 Member

    Morning,

    So last night I thought I’d give it another go so before I touched anything I just fired up the boiler to see what happened.

    On the lowest temperature setting, the boiler ran for maybe 5 mins and then shut down.

    I checked the pipework at the top of the boiler which was hot, the flow into the pump which was hot, as was the pump body and maybe a foot of pipework after the pump.

    Checked all rads upstairs and downstairs and they were all filled, no air came out same with the pump.

    Someone else suggested I try to drain with the mains water on so the system would keep filling in a loop, so I thought why not! This time I used the drain point on the boiler, which as soon as I opened it there was an initial whoosh of water out the hose, followed by a steady stream but eventually the water ran out!

    I thought that with the mains still on, I’d just be pulling new water through the system but I’d ended up emptying all the upstairs rads again – which I didn’t think was a good sign!

    Turned off the drain and tried to fill the rads from the F&E, got a small spurt of air followed by nothing – started to think blocked cold feed again.

    I turned the drain back on and there was a small trickle until I put a separate drain on the flow of the kitchen rad and there was a sudden whoosh of water through the drain on the boiler and the flow was far better than the last time, I could actually hear the water rushing into the boiler.

    So off went the drain, back upstairs, and the rads hissed like crazy and one by one filled back up from the F&E tank.

    At this stage the system was in this state: rads had filled from F&E, all the rads had been bled, the pump had been bled.

    At first I thought I’d try to get the flow to the furthest rad so closed all the others off – nothing, not a thing. Went back to the rad in the same room as the pump and with everything else shut off even that wasn’t getting hot.

    I didn’t dare do the screwdriver in the pump, but I sat and turned the pump off and on to 3 for about 10 mins and finally got one single radiator hot – then I just gave up because it wouldn’t flow anywhere else. Did a quick fire up this morning and, as above, boiler fired for a couple of minutes and pipework up to, including and a foot passed the pump hot – everything else cold.

    Is there anything that is pointing to the pump being knackered? That seems to be the one thing that has been a constant in everything I’ve tried and everything else I’ve tried, draining, filling, draining, filling, getting air out etc etc just hasn’t made a difference – I’m thinking if it’s the pump, I could be doing this until Christmas and the water is never going to go anywhere!!
     
  15. Does the pump have isolating valves on it? If so, it can be quickly removed.

    How to test? Not sure, but perhaps - if you are careful - you could immerse the inlet/outlet in a pale of water whilst keeping the leccy section well clear? (Shoot me down for that one...)

    Akshully, if you do have isolating valves on the pump, then could you contrive a fitting to connect your hose to the outlet side with a short hose to a bucket from t'other side, open both valves and use mains flow to force through? The problem with a pump is that as soon as it hits an air pocket, it stops pumping as it has nothing to 'catch'. Mains water would still push through, tho'.

    Or, before even that, run your system as before for a couple of minutes until it gets to the point that it clearly ain't pumping, and then slacken one end fitting and see if air comes out?

    Wait a minute - have you had the end screw off at all to see if air comes out? Ie - the bleed screw on the pump? Is the pump fitted so that the end with the bleed screw is slightly above horizontal (er, after checking that that is the way it's meant to be...)?
     
  16. nfollows82

    nfollows82 Member

    There are isolating valves on either side. They are the ones that look like old fashioned taps with the wheeled head. No idea if they close properly.

    I'm pretty sure there's no air in the pump as soon as I unscrew the front screw it releases water and I can hear water in it when it's on.
     
  17. It's a bleedin' mystery!

    Any chance of a photo of the boiler/cylinder/3-port valve/pump area?
     
  18. nfollows82

    nfollows82 Member

    Hi all,

    So I decided to have one more go at this damn thing and I thought I'd managed to fix it but it's still not working as it should.

    I've bled again, tied up ballcock and drained the dropfeed rads. Filled via the tank and bled each rad in turn starting downstairs and working my way upstairs including the pump.

    Turned it on with all valves fully open and I got 3x hot rads upstairs and nothing downstairs. The rads downstairs had hot flow pipes and started to warm up a little so I thought it was a balancing issue.

    But I've tried turning the rads off upstairs to force the flow through the rads and I can't get them hot.

    I've even had the pump off this time and made sure it was rotating and it is/was when I'd got it off.

    The problem is still that the temperature at the boiler is too high preventing it from firing and even with the pump running and the boiler not fired up the temperature isn't really reducing that much.

    The system is full of inhibitor now so I really don't want to go through another draining process so has anyone any ideas now?

    The only thing that hasn't been changed is the pump but with it spinning I thought that meant it was working so I have left that alone.

    There's no air in the system, I've bled the rads again and there is no air in the system and there's no air in the pump so I don't see how this can still be an air lock problem.

    Before I go out and spend £100+ on a new pump is there anything else I can try?
     
  19. plumberboy

    plumberboy Well-Known Member

    Have you tried my trick??
     
  20. nfollows82

    nfollows82 Member

    No not yet. Just so I'm sure what you're saying, when I remove the bleed screw from the pump there is a spinning part of the pump with a flat head screwdriver thread. Do I just put the screwdriver in here and hold it shut? What's the difference between this and shutting the pump on and off?
     

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