Combi or heat only?

Discussion in 'Plumbers' Talk' started by Hunters123, Jul 15, 2014.

  1. tom.plum

    tom.plum Screwfix Select

    Mr Devs, it is a store but under pressure, like a pressure vessell it stores the water like a big balloon so it increases the pressure but only for a short period, like a balloon will deflate so will the acumilator, ;)
     
  2. tom.plum

    tom.plum Screwfix Select

    also someone mentioned a combi but with a storage vessel and why were there not more of them, well because they are troublesome, they are 'half way house' systems, you are losing the benefit of only heating the water you need for having hot water a little bit quicker, and all the time the boilers switched on its heating the stored water just in case you might need it,
     
  3. Sean_ork

    Sean_ork Screwfix Select

    that's a bit misleading

    the small tank is heavily insulated, so it's effectively just a smaller cylinder - so it will retain it's desired temperature for most of the day - so the only heating required is when the store is depleted through use

    the advantage being that you get hot water at the tap a little quicker

    they aren't at all troublesome, oil fired boilers have had then as standard for decades
     
  4. Thanks Mr Plum - that makes sense.

    Hey, Sean, my GlowWorm has one of them little stores I think - gawd knows where inside, tho'. It certainly has 'pre-heat' or whatever it's called; darned thing comes on every few minutes to keep the bludy DHW water warm, and I can't turn that feature off without turning the DHW control to the section where it only provides one temp and that's 'bludy hot'.
     
  5. Sean_ork

    Sean_ork Screwfix Select

    there's something wrong there then DA, it should not be doing that - unless you have it in a cold unheated area such as a garage so it's loosing it's heat very quickly
     
  6. Sean_ork

    Sean_ork Screwfix Select

    what's the model number I'll bet you a pound to a penny that there is an option to turn this ''feature''
     
  7. tom.plum

    tom.plum Screwfix Select

    like I said Mr Devs they're troublesome, :(
     
  8. Yeah, and my boiler is too... :rolleyes:

    It' a 30CXi.

    Ok, I exaggerate about how often is comes on, but it must be every 20 mins or so?

    I think it also has a programmer built in so it knows when demand will be and triggers it around these times. So very possibly it's only at times of anticipated 'demand'.

    The pre-heat can be turned off by turning the DHW temp control down - ie there's a point around a third of the way round where it goes into the 'pre-heat' setting and the further you turn it the hotter the water, with pre-heat. If you turn it below this marked 'point' the pre-heat goes away. But, here's the thing, even tho' the control has a good third of travel in this non-pre-heat position, the water temp is always too far hot - it doesn't appear to be adjustable.

    Hey - I'm happy - I love my combi... :)
     
  9. Sean_ork

    Sean_ork Screwfix Select

    delete the zero change the mins for hours and times the 2 by 3 more like - and it'll cost you about £20 a year for the gas :rolleyes:
     
  10. Pfffft.

    Anyways, I'm happy with my combi - it's awesome.
     
  11. plumberboy

    plumberboy Well-Known Member

    Dev's,the good thing about accumulators are that you can have combi's and unvented cylinders even with poor mains pressure and flow.You can install as many as you like so someone with poor flow and a few bathrooms I may install two 500L accumulators,that's over sized but will give great flow rate all day especially if they have poor flow rate incoming from the main.;);)Also Tom was spot on with his description .
     
    Last edited: Jul 17, 2014
  12. selqes

    selqes New Member

    By saying accumulator he probably means a water storage. You can customize a combi-boiler by having a storage tank with an immersion heater at the inlet. It takes in the cold water and heats it up. So this implies the boiler does no work. I have seen a similar system along with solarimmersion at my friend's place.
     
  13. Crowsfoot

    Crowsfoot Screwfix Select

    Domestic accumulators will be an expensive addition to what is already a pretty expensive layout.
    I would say at the reserve of only the most affluent members of society and perhaps a few folk who are always seduced by gizmo's and gadgets (more money than sense brigade).

    Methinks here's one destined for the plumbing museum of "obsolete oddity's" in just a few years time.

    Keep plumbing as simple as possible is a golden rule.
    Tappy,
     
  14. plumberboy

    plumberboy Well-Known Member

    Tappy,I agree keep plumbing simple,but accumulators do offer some people with poor flow and pressure a greater system.
    There are lots of them out there now and they work well,but you can't beat your standard plumbing systems to work on.
     
  15. tom.plum

    tom.plum Screwfix Select

    I agree with the keep it simple rule, but an accumulator is a good gizmo, you can zone it as well, for instance if you have an attic area with a poor flow you can 'aim' the accumulator at that area using non return valves so that if somebody turns a tap on downstream the attic is unafected
     
  16. Crowsfoot

    Crowsfoot Screwfix Select

    I can now see there is a nitch in the market for an accumulator and that they're not a new idea either.

    I can't recall ever fitting one nor even coming across one fitted in over 40 years of plumbing!

    Having said that there's always this coming week.................
    Tappy,
     
  17. G&W Plumbing & Heating

    G&W Plumbing & Heating Active Member

    A good combi will deliver around 15l/min, unvented 26l/min or 80+l/min with accumulators connected.
    There's only one answer in my opinion, go unvented but check the mains 1st to see if you need accumulators
     
  18. How will an 'unvented' deliver 26lpm when the mains is only, say, 16lpm - which is very typical?

    For how long will an 'accumulator + unvented' deliver 80lpm if, again, it's fed by only a 16lpm mains?

    Genuine Qs - I wanna know.
     
  19. tom.plum

    tom.plum Screwfix Select

    a unvented has a built in accumilator/expandtion vessell, so that boosts the standing pressure, then if you add other accumilators you are adding more banks of built up pressure,
     
  20. Oooh, you are sooooo avoiding my question... :p
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice