Central Heating pump orientation

Discussion in 'Plumbing and Central Heating' started by Anastasia, 30 Dec 2005.

This topic originated from the How to page called Problems associated with noises from the central heating system.

  1. Anastasia

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    I am having trouble with a noisy C.H system and reading some of the other comments got me thinking. I have had my C.H pump off for flushing and have now got doubts that I put it back the right way round. Should the arrow point away from the boiler or towards it?(and towards the header tank in the attic) :rolleyes:
     
  2. weareleeds

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    What kind of system is it gravity or fully pumped where is pump is it upstairs or down etc etc etc
     
  3. Anastasia

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    weareleeds

    I believe my system is gravity fed. The header tank is in the attic and is open i.e. just got a plastic lid on it. It is topped up via cold water mains through a normal ball cock system. The outlet is at the bottom to one side.

    The pump is at the top of the stairs in the airing cupboard with the boiler and the hot water cylinder. The boiler is at the highest point then the pump and lastely the hot water cylinder.

    I am not happy about turning this pump round in case I cause irreverible damage. I have this vision of my boiler going into orbit one of these days. :LOL:

    What do you think. Have I explained my system correctly. :confused:
     
  4. Softus

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    Follow each pipe from where the pump fits, as far as you can reasonably see it, and post back with what you find along the way and at the end of it. For example, if one pipe leads to the cylinder then it would be good to know which part of the cylinder it connects to. A photo would be good too.
     
  5. Anastasia

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    Softus

    Sorry, I do not know how to post images to this forum, but if you send me you E mail will send them to you.
     
  6. Softus

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    How to post a picture
     
  7. Anastasia

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    Re: Posting Pictures

    Thanks Softus for the advice. Let me know if you can see these photos.

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  8. JohnD

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    You say it is noisy. Do you mean gurgling and rushing noises, or do you mean clonks and bangs, or do you mean ticking?

    (edited to say, was confused by that white airing rack with the blue plastic fittings)

    You also have a long-term leak from that thing that might be an automatic air release, that wants fixing more urgently than anything else I can see.
     
  9. Anastasia

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    That brass thing (release valve?) was changed by British Gas about 12 months ago. I think the leak stains occured before it was changed.

    Getting back to my original question - From where the pump is situated, which way should the flow be going? (arrow on pump body). Currently it is flowing away from the boiler i.e down. Is this correct.?

    The noise is definately banging in the boiler / pipes
     
  10. JohnD

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    Sorry for avoiding the question. The more important thing about the pump is the relative position of the cold feed/expension and the vent pipes. Preferably these should both be on the suction side of the pump, and close together. Numbering your visible pipes from left to right, top ones first, as seen in your second picture, and expecting the clean ones to be hot and the dirty ones to be cold. To give the correct answer I think we need to be sure what each pipe does:

    1 is a cold 15mm pipe, probably the cold water main to a big tank in the loft

    2 is a hot 22mm pipe, I see it comes from the hot water cylinder, so must be going off to feed the bath taps.

    3 is a cool 22mm pipe, what does it do? Does it bring cold water from the big storage tank in the loft and deliver it to the bottom of the hot water cylinder?

    4 is the air release when it goes upwards, and also goes into the boiler. When it goes downwards, is it bringing the water from the radiators (so will be cooler than pipe 5)?

    5 (RHS of your picture) is a very hot pipe, comes out of the boiler and then goes upwards, is it the vent pipe that is bent over the small tank in your loft? Or, does it got into the bottom of the tank in the loft, to supply water to the system? The downwards run of this pipe goes to the pump, then a relief pipe with control valve. It continues down, can't see where it goes, can you have a look please? I would expect it to go to the 3-way valve but for some reason it does not go directly there.

    In the lower picture the pipe going into the bottom of the boiler looks like the gas supply, so not relevant here.

    Can you have a look round the pipes and see where they go please?

    Also, have a look in the small feed and expansion tank, see what colour the water is, and what colour is any sediment on the sides and bottom of the tank.
     
  11. Anastasia

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    Thanks John D for you thorough posting.

    I have invented a good New Years Eve party. This is how it goes. Get all your family round and ask them all to go up into the loft and identify what all the pipes do and where they go :LOL: It makes it more fun if you haven't got a loft ladder and the only lighting is from a torch with fading batteries. I must admit Grandma wasn't for going up there until we gave her another sherry!

    Seriously though I have worked through your posting and these are the answers to the best of my knowledge.

    No 1 pipe is from the cold water feed which goes to the header tank (small) and one of the two big tanks

    No 2 pipe I assume you are right here. It drops back into the top of the 2nd cold tank in the loft.

    No 3 pipe does go to the bottom of the cylinder. It comes from the bottom of the 2nd big tank in the loft When the red tap is turned off then no water comes from the hot taps in the bathroom

    No 4 pipe goes through the floor and is cooler than pipe 5)

    No 5 pipe goes to the bottom of the small tank in the loft, and does go to the 3 way valve, but a smaller pipe goes off through the floor

    I hope all that helps. I have added more pictures of the lower half of the system. Happy New Year to all fellow sufferers ;)
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  12. JohnD

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    OK then. It appears that pipe 5, which looks to be 22mm, is a combined feed and expansion pipe, and vent pipe (inless you can find another pipe bent over the small tank?)

    So I see no reason why the pump direction (flow is downwards) should not be OK. I was particularly anxious that you might have a separate feed and and expansion pipe, and vent pipe, and their arrangement would have been critical. But yours appear to be combined, which is OK. If it was on the pressured side of the pump, you might get water going up the pipe on start-up, but this is not a prob on your installation.

    BTW, get a green pot-scourer and some fairy liquid on pipe 4, it will always worry anyone who sees it, and if you get a fresh leak, it won't show.

    If your boiler is making bumping and clonking noises, it is more likely scale inside (like a kettle) which will be worse because additional water will have gone in to replace that lost through the leak. You usually hear these start after the flame has fired up as it gets hot, and stop shortly after the flame goes out, until it starts to cool. Get some chemical cleaner and follow the instructions; after flushing use an inhibitor and a boiler noise reducer.

    Can anybody spot anything I've missed?
     
  13. Softus

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    When you say that pipe 4 is cooler than pipe 5, is this with the pump running or not running?
     
  14. Anastasia

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    Happy New Year everyone.

    Softus - Yes Pipe No 4 is cooler than pipe No 5 with the pump running (which it does all the time by the way whilst the heating is on)

    The thing that raises doubts with me regarding the boiler "kettling". Why does it only do it after the first 10 minutes of the heating coming on and never again. I know for a fact that when the banging starts, the pump stops (or maybe stalls possibly due to it getting filled with a slug of air). The banging stops when the pump noisily starts up again. Then everything is fine.
     
  15. bab

    bab

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    Taking at face value that the boiler flow is on the right on the boiler yes the pump is on the right way.If the header tank in the attic is sat on the joists then u have very little static head between where the combined feed & vent tee off on the top right of the boiler.Is the pipe coming out of the small tank in the attic 15mm or 22mm ? Is there a t joint close to the tank with a vent going up & over the top of the tank & if so is that 15mm or 22mm. Did u flush the system your self or did BG do it 4 u. Did u alter the Ballancing valve on the by-pass(re headed gatevalve to the left below the pump) while flushing.The Myson Appollo is low water content alloy heat exchanger that will over heat & kettle quickly.If the system needed flushing it probably needs the boiler descaling. The boiler has a low & high switch thermostat inside the slide window do u get the same problems when its on low?
     

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