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Discuss unvented hot water system vs Combi, need help. in the Plumbing Forum area at UKPlumbersForums.co.uk.

  1. Al cw

    Al cw New Member

    Good afternoon everyone. Alex here and new to this site. I am not a plumber but would like some professional advice from the experts (you guys/Girls) I currently have a unvented hot water system with a boiler in the kitchen ( a glow-worm mk2 ) and hot water cylinder in the airing cupboard and 2 water tanks in the loft space. we are having a garage build very soon and the idea was to move the new boiler into the garage to free up some space in the kitchen. the boiler will go just the other side of the wall it currently sits at the moment so hopefully not to much messing about with pipe work etc. I though about replacing the cylinder as well with a bigger one as the one I currently have is a albion indirect 117 litres. which by the looks of it is pretty old. I friend said to get a combi boiler therefore getting rid of the water tanks in the loft space and getting rid of the hot water cylinder in the airing cupboard. we current have a power shower at the moment and the though of a combi sounds great. I just don't want to lose any water pressure with the shower by going with a combi. he said I wont lose any pressure as the cold water feed coming out of the kitchen tap is pretty good from what I see of it. and the though if having an airing cupboard to use as space again would be good.
    after talking to a plumber friend of mine he said that I will lose pressure with the shower. and the same for when the shower is on and someone runs a tap etc. can someone put my mind at rest and inform me the best way to go. some plumbers say go with combi others say stick to what I have just update boiler and cylinder. Many thanks look forward to hearing from you all.

    Alex
     
  2. Gasmk1

    Gasmk1 GSR

    how many bedrooms and bathrooms do you have. there are a few options, if you move the boiler to the garage and have an unvented cylinder installed and turn the system to a sealed system, this will do a way with the tanks in the loft this is assuming you have good cold water pressure. you could also move the cylinder into the garage near the boiler. you could have a storage combi boiler like the Viessmann 111 this is a great boiler if you have a good mains pressure as it is a small unvented cylinder that replenishes itslef while running hot water. i am sure others will jump in.
     
  3. townfanjon

    townfanjon Trusted Plumber GSR Top Contributor!!

    Combi verses unvented , ( assuming a unvented can be fitted ) usually boils down to hot water demand , if you need or use a lot of hotwater go down the unvented route , if you dont , go down the combi route .
    I do agree with gasmk1 ^^^ a storage combi may be the way forward
     
  4. king of pipes

    king of pipes Trusted Plumber GSR Top Contributor!!

    Recently did the alpha boiler course their flow smart system would be worth considering, boiler and 50 or 100 litre store of hotwater it can run three showers at once providing you have good incoming main pressure 20 + litres a minute cheers kop
     
  5. Al cw

    Al cw New Member

    Gasmk1. I live in a 3 bed semi with one bathroom so not using a lot of hot water. the washing machine is on during the day and the dish washer goes on last thing at night when we go to bed. we don't use that much hot water. wife might have a sometimes long shower but apart from that nothing crazy. was going to look at pressured system but all comes down to money at the end of the day. how would I find out how good my water pressure is apart from just turning the tap on. it might seem good to me but rubbish to others who knows this stuff.
     
  6. king of pipes

    king of pipes Trusted Plumber GSR Top Contributor!!

    Combi would probably do what you need then Al
     
  7. Al cw

    Al cw New Member

    Thank you king of pipes. can you recommend a half decent boiler. and how can I see what my water pressure is. is there a minimum that I will need so I don't lose the pressure in the shower. if not I there anyway I can get around it with a combi boiler like keeping a tank in the loft for the shower but losing the hot water cylinder.
     
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  8. king of pipes

    king of pipes Trusted Plumber GSR Top Contributor!!

    Worcester greenstar 34cdi classic will suit you nicely other will have their favorites 15 litres a minute cold main flow needed to provide a good hotwater flow rate this can be measured with a weir cup and suitable pressure gauge any decent engineer can do this for you cheers kop
     
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    Last edited: May 20, 2017
  9. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

  10. Al cw

    Al cw New Member

    thanks guys really grateful for all your info.
     
  11. Al cw

    Al cw New Member

  12. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Your best option would be to ask your installer which he option he would like (you or him buy the big items) most of us normally get everything we need, as we can make sure we have the right bits / everything but worth an ask
     
  13. king of pipes

    king of pipes Trusted Plumber GSR Top Contributor!!

    I have been getting the jobs quoted and getting the customer to pay for the bulk of the materials which are then deliverd direct for me to install , the main reason is to stay under the VAT threshold , go with a reputable local installer who will look after you and your boiler in the future , adding a worcester mag filter and controls it will add a years warranty for each heres one i did recently to give you some idea before and after best of luck kop.

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  14. Al cw

    Al cw New Member

    Thanks KOP works looks good by the way. sorry to nag you. if I did go combi boiler would I need to buy a new shower as we currently have a power shower.
     
  15. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Yes but could be changed easily ish
     
  16. king of pipes

    king of pipes Trusted Plumber GSR Top Contributor!!

    As shaun said yes you would but not a problem
     
  17. Al cw

    Al cw New Member

    Ok thanks guys really don't know what to do know. just had bathroom tiled so really don't want to start hacking about with new shower. have you guys every changed a gravity feed system like mine to a combi boiler. did you notice the pressure drop at all or was everything still the same as before.
     
  18. king of pipes

    king of pipes Trusted Plumber GSR Top Contributor!!

    Yes bud we do it quite alot it will be alot better , heat up time is quicker your bills will be lower heating is more controllable and you only heat the water you need post a picture of your shower and we can see what needs doing cheers kop
     
  19. Al cw

    Al cw New Member

    Iv got an aqualisa aqua stream it has 2 pipes coming in the back which I presume are hot and cold feed. and a small electrical connection for the pump which is in the loft. its only a small transformer. with a combi how is the water temp controlled from the shower is there is a cold water feed coming into the shower as well as a hot feed. sorry don't mean to sound dumb this is all new to me. i'm quite happy to go combi but the shower is the big one we have a nice pressure on it and have been having showers at my family's home while our bathroom was being pulled about. there pressure was really bad. hence i'm a little ocd on the shower pressure. :)
     
  20. Harvest Fields

    Harvest Fields Trusted Plumber GSR Top Contributor!!

    If you do not want to alter the tiles or remove the shower then stay with the system you have, ie boiler and cylinder. Your shower cannot run on mains pressure so that rules out a combi and an unvented cylinder. The smart option long term in my opinion, is to remove the shower and alter the pipework behind to fit a normal bar mixer shower. Fit something similar to a Vaillant 835. You will get a slight pressure drop in the hot water but it will still be very good.
     
  21. Al cw

    Al cw New Member

    Thanks you. that sound like a more suitable option.
     
  22. king of pipes

    king of pipes Trusted Plumber GSR Top Contributor!!

    Dont panic about it if you have a few tiles left or they are still avalible its a simple half day job to alter this many heating installer do bathroom fitting and tilng i do and its a simple job to do i would recommed the triton dene bar shower mixer solid brass construction very well built and under £100 cheers kop

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  23. king of pipes

    king of pipes Trusted Plumber GSR Top Contributor!!

    Post a picture of your shower so we can see whats worrying you cheers kop
     
  24. Harvest Fields

    Harvest Fields Trusted Plumber GSR Top Contributor!!

    It will probably look something like this. (Hopefully)

    image.png
     
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  25. Al cw

    Al cw New Member

    thank you KOP and yes Harvest fields like that but in silver. :)
     
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