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demand

In economics, demand is the quantity of a good that consumers are willing and able to purchase at various prices during a given period of time. The relationship between price and quantity demand is also called the demand curve. Demand for a specific item is a function of an item's perceived necessity, price, perceived quality, convenience, available alternatives, purchasers' disposable income and tastes, and many other options.

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  1. Ted808

    combi fires up - without demand

    Went to a main combi, not serviced or looked at for years- can't be that old 5-7yr but shoddy install. Expv flat as per. Got the beast going but it fired once or twice without demand. Dirt in the system right? Sticking flow switch or ....? any thoughts? :eek:
  2. F

    Grohtherm 3000 (19665) - Boiler not recognising demand for hot water

    When attempting to use the shower our combi-boiler does not fire up in response to the demand for hot water. However, if using the Exafill to run water into the bath then the boiler DOES fire up - as it does also with other hot taps in the house. British Gas service engineer has checked the...
  3. T

    Should Ideal Logic Combi ESP1 35 show demand for heat when thermostat esrpt4 doesn't need it?

    Hi all, I've just moved in to a new build with the above boiler and two thermostats (one upstairs, one downstairs). The other day we had an issue where the heating upstairs stayed on no matter what the thermostat said, I managed to factory reset the upstairs thermostat and since then the rads...
  4. C

    Opinion request on hot water demand

    Looking at something like a megaflo unvented, typically you heat this to 65 degrees. Most of the day, I have hot water sitting in the tank not being used, and if I do not draw any off, the insulation is very good and keeps it at 65 degrees. If I draw hot water from the tank it gets colder as...
  5. M

    Grant Vortex Combi 21e Constant Demand

    Hi Folks, I'm new on here and this is my first post. I have one of the Grant combis, and wish I'd never had it fitted :disappointed: The latest one is no hot water :disappointed: I've noticed over the last few weeks that the temperature of the hot seems to be hot to start with, and then...
  6. K

    Unvented hot water system noise when hot water demand is made

    Hi all, Ready for War and Peace ? Hope you are all sitting comfortably, so let me begin...p.s. I am not a plumber, I work in IT so sorry if incorrect or wrong terms used ! We have a unvented hot water system, installed in Jan 2014. FlowMaster cylinder; Zilmet 11H HY-PRO (18ltr / 3bar...
    • kirks06
    • Thread
    • demand expansion hot hot water hot water system noise plumber pressure system unvented vessel water
    • Replies: 11
    • Forum: Plumbing Jobs | The Job-board
  7. P

    Ferroli Optimax - heating staying on permanently with NO demand

    Hi guys, I know, ferroli again(bag of s**t) seems to be operating the heating constantly but stat is not set to call, Hot water demand symbol appears to come on though, with no taps open. Any suggestions? Cheers Pooly
  8. W

    Glowworm Energysaver - always on / reporting demand

    Hi! I can't find another post on the same subject but apologies if I have missed one. i moved house last November and soon after had a free BG boiler service which reported no problems. recently we had a surprisingly large gas bill and it got me thinking: * the boiler is in the attic above the...
  9. L

    Ideal Vogue C32 hot water demand

    Hi all, just to say I'm not a heating engineer nor gas safe registered and I am not going to attempt any gas work on the boiler. We've just had a new ideal vogue c32 commissioned. Noticed today that the boiler fires when cold water taps are used. Even the outside tap which is just after main...
  10. C

    What size boiler do I need?

    I am a newly registered gas engineer and I am getting a quote together for a job in an industrial unit. There is an old floor standing boiler, which runs 11 rads. It is roughly 21 meters to the furthest rad. The customer would like to fit a Worcester Bosch Combi boiler but I am unsure what size...
  11. finchy01

    Power tripping when dhw/ch demand.

    Evening all, I had a call back today from a month ago or so. The power trips when a) immediate demand for dhw and b) a few seconds after demand for ch. We replaced the programmer, cylinder stat and 3 port before (a different reason). This has only started a couple of days ago so I know it's...
  12. G

    worcester 24 cdi - after hot water demand noise

    sorry, thought I was logged in :smile5: Hi, just looking for opinion on a tapping noise our boiler has only recently started doing..Only happens just after hot water is turned off, and is loudish tapping noise for maybe 1 minute with time between tapping getting longer till it stops...
    • greenockboy
    • Thread
    • after boiler coming demand happens hot hot water noise tapping water worcester
    • Replies: 3
    • Forum: Plumbing Jobs | The Job-board
  13. C

    Glow-worm Flexicom 18 sx 'No demand for hot water/heating' can you help?

    Hello there, I have a Glow-worm Flexicom 18sx boiler which has stopped working while we were on holiday. I.E. everything seems fine with the controls & bolier but there is no longer hot water or heating on demand. Now, as we were away, obviously nothing has changed, so I've tried to diagnose...
  14. T

    Heat slave II nosie when HW demand

    Ughhh annoying, literally just fitted this boiler 2 weeks ago, got a call today ''Its making a whooshing noise when we run the HW tap'' So I'am going out to look at it for the 2nd time same problem on a bank hol monday :( First time I went it was just a load of air in the heat bank so I just...
  15. H

    Vaillant ecoTEC plus 612 query

    Hello I have a new Vaillant system boiler which is very slow to respond to heating demand. When it starts in the morning and there is a high demand for heat it only fires up to about 1/3 power and stays there for about 30 minutes, or more, before going up to full power. I touch the return pipe...
  16. J

    Worcester Condsen. Boiler. Intermitten CH failure. Me and Gas man at witts end

    Sorry to be long winded but..... Holiday Flat. 5 year old Boiler in loft space. Working Perfectly until Oct 2013 -Worcester/British Gas fit Model ZWB 7-29 CC1 Background - We have the thermo set for practically 24 hrs over 2 cycles at 15c. 08.30am -20.29 & 20.35 - 08.25am. (specific reason...
  17. J

    What system would you recommend for this hotel?

    I'm interested to hear what boiler cylinder or cylinders etc you would recommend for this hotel. They currently have low pressure system, with old open flue boiler. They looking to have the lot completely replaced and upgrade to a unvented system. The hotel has 20 radiators, 8 Mixer showers, 4...
  18. M

    BAXI 105e Instant hot water getting colder as demand goes up

    HI I have a baxi 105e instant, if i open the Hot water type slightly i can get continuous very hot water but if i demand more flow (ie open the hot water tap more) the temperature decreases. I have checked and changed both the DHW and divertor valve diaphrams (both seemed ok) Thanks
  19. galaxy_plumbing

    chaffo. britony 2t pilot on when no demand

    Hi guys, absolute pain this one. Went to change diaphragm but none of my ones I had would fit. So put it back together and this bugger wouldn't work correctly. Spent 4 hours there today, had everything apart, cleaned, but no joy. Ignition is ok but as soon as you twist the knob anticlockwise it...
  20. D

    Boiler fails to switch off when CH and HW demand removed

    I have a Worcester Bosch 18Ri boiler which was installed about 3 yrs ago. Recently the system pump failed and was replaced.I then noticed that the boiler and pump were occasionally coming on in the middle of the night(Temperature in loft about 50 degs F, too high for Froststat) even though...
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