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No Central heating without turning hot water on

Discussion in 'Plumbing and Central Heating' started by shan70, 23 Jan 2016.

  1. Echo the husky

    Echo the husky

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    It would have to be otherwise the cylinder stat wouldn't be able to close the 3 port valve. Who is going to bet it is wired in 3 core flex using the earth as one of the live cores and with the stat left un-earthed? It could be ok providing the stat is class II and the earth core is correctly identified at both ends.

    Some more photos would help confirm. Apologies if I sounded unnecessarily aggressive in my last few posts, I spend my entire life correcting s*** wiring similar to what has been shown in your photos, I don't wan't to see it being made worse!

    I have literally just got back from a call out which would have been avoided if it wasn't for the incompetence and laziness of the previous person who worked on the installation.
     
  2. shan70

    shan70

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    Thanks for all information. Before doing anything I will take the picture of junction box's inside. It is in the loft. I need to wait till Tuesday to arrange battery operated light and right time to switch off whole house power. I think my main problem will be taking cable from programmer to junction box, accessibility is not good. I noted stardanny's point that I can move programmer to more better location. The programmer is currently screwed in the kitchen tiles, so if I move it then I need to hide the holes in the tiles. Also I need to route the thermostat wires as well. So, my option is to use single core cable (with additional layer of insulation off course) and run to the junction box. Taking the cable though ceiling is the main obstacle.

    2 more questions,
    1) My intention is to reduce gas bill. Is it worth the trouble? My house is 1930 solid brick, 4 bed detached dormant bungalow. Sat-Sun-Tues-Thursday heating run 24 hours, Mon-Wed-Fri run except office hours. I have a baby boy and an older boy. My wifee always complain it's cold even I am sweating.

    2) LP241/LP522 back there are six more holes, can I convert it to a LP722? I can only think the difference between all these programmers are the firmwire, different module of the software is activated and sold as different product. I can solder 3 x 2 pins there and find jumpers and see the effect. Do anybody have a LP722 programmer? Can you share the back picture of LP722?
     
  3. shan70

    shan70

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    Hi,
    I took a picture of the inside of juction box, everything seems connected except terminal 8 which should connect to programmer HW-OFF. In terminal-16, GY colored cable is already used for non-earthing purpose. Is it really "prohibited" to use other purpose even it's labelled/marked properly.

    The lifestyle programmer manual written, "Lifestyle units are double insulated and need no earth connection, but an earthing continuity (loop) terminal is provided for convenience". Easiest solution is, using the GY wire of programmer cable (yellow label) to terminal-8 in junction box and other end to terminal-1 of programmer. Then getting another earth wire connected to any of the bottom six terminal. I found there is a 3 pin socket terminal near. I have hand held DVM which I can use to check continuity between socket and earth terminal in the junction box. But if it's really not allowed or, illegal then I need think route to use a 6 core cable or, a single core cable from programmer to junction box.
    20160126_133244.jpg
     
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  4. Echo the husky

    Echo the husky

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    Oh look, the cylinder stat is wired in 3 core flex with the earth used as HW satisfied, what a a surprise. It's nice to see the wiring centre fixed to a wall as well.

    At least all the other wiring is there and you only need to get a wire to terminal 8. I use 7 core cable between the wiring centre and the programmer as it's easier to get hold of than 6 core. Any decent wholesaler will stock it and sell by the meter. The unused core being put into a small connector block at each end to keep it safely out of the way.

    That joint in the 3 port valve flex just visible in the left of the photo needs properly enclosing as well. What cylinder stat do you have fitted? If it requires an earth you will need to change the flex to 4 core.

    Thanks for posting a clear photo of the wiring centre.(y)
     
  5. chipcutter

    chipcutter

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    This may have been the original post you saw? positive result, but you will need an electrician. See Fault 2, may be helpful, but check your Grundfos pump?

    This was the outcome...

    ...things were really getting bad with the heating so my son came round on Tuesday and went through the electric circuits (he's an electrician). CH had been very intermittent and only coming on, to some degree, when water was called for as well, except that it totally failed on Tuesday!!
    After one and a half hours of diagnostics he had found TWO faults - one was quite surprising; the pump. We have never heard or felt the Grundfos pump working although the little LED would come on when engaged with the hot water being switched on. Fault 1 - The pump was in fact FAULTY; it has only been in use for about 7 weeks since we switched it on in late November. All that could be heard was a little dull tick every 2 seconds and we think it was only rotating, if at all, very slowly.
    Fault 2 - The other main fault was the programmer on the wall, a relay had failed on the CH side although the LED came on as normal. My son realised this and simulated it by making two conections on the separate box assembly that joins all the wires together into one box (the one with all the long row of connector points); it had something to do with the white cable, however, to cut a long story short he got a new programmer box and a new pump in case. He fitted the programmer and immediately ALL functions were re-instated. We changed the pump and immediately realised that the old (but new last year) one was obviously faulty. You can quietly hear the latest one happily turning at speed and gently feel the vibration of its movement.. result happiness!
    Not very happy with the original fitter that fitted the duff one as he couldn't have checked it very well, he could have cost me a fortune trying different things. Just shows how important electricians are and how some problems can be found purely through electric diagnostics... lessons learned.
    We have subsequently found out that there was a bad batch of Grunfos pumps of this type last year - looks like we were unlucky.
    EVERYTHING works now as normal. Thanks again.

    Read more: http://www.diynot.com/diy/threads/c...til-hw-switch-activated.447814/#ixzz3yXrsKVzW
     
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