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Hardware Thread, do you keep projectors on all day? in Technical; Just had new projectors installed, want to prolong bulb life as much as poss so is it better to keep ...
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    chrbb's Avatar
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    do you keep projectors on all day?

    Just had new projectors installed, want to prolong bulb life as much as poss so is it better to keep projector on all day with blank screen saver so kids not distracted or to switch on and off (with remote) as required?

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    Re: do you keep projectors on all day?

    Yes we advise teachers to leave them on all day, and use the No Show/Blank function when they're not in use; as we were recommended by Promethean. The less the lamp has to warm-up-cool-down the longer it should last, in theory

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    Re: do you keep projectors on all day?

    God no I get furious at people leaving them burning away all day, its like the saying about flurencent lights are best left on all day etc its just not true.

    Fine going from period 1 to 2, but that room may be left empty from period 3 - 6 which may be a good few hours so you are wasting bulb life time. Remember these projectors count the hours they are used and even on "No Show" they are still counting so you are just kissing goodbye to bulb life as they will expire at the set level, fine you could reset the bulb life but that is running the risk of a H&S issue if it actually goes bang, and I can tell you that you don't want that, I've had that happen and it was not fun at all. So long as you turn them on and off correctly IE with a remote or projector buttons not just the mains switch on them, so that the fans continue to run etc you will be fine, but I would say going from P1 to P2 is fine, but think and use common sense.

    Oh and Craig, rule 1 of IT never listen to what the bloke that sold you it said, Mr Promethean is bound to say yeah leave it on 9-5 its better for it, no balls to that, he's thinking that bulb lasts 2500hrs, so 8hrs a day, 5 days a week so thats about 40hrs a week of on time a week = lots of spare bulbs needed! I've seen it happen and they go though bulbs left right and centre, where as my method I am still on the delivery bulbs in my IT centre 3 years on, and the units only do 2000hrs a bulb, and they get changed at 2000hrs so thats not bad at all.

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    webman's Avatar
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    Re: do you keep projectors on all day?

    Well we must have extra-tough lamps up't north, we're only just replacing lamps in our projectors that were put in 5 years ago

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    Re: do you keep projectors on all day?

    Think of all that energy you are wasting they draw a lot of current them things, think green or else we will garnish ur salary for the electric wastage

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    Re: do you keep projectors on all day?

    @John

    Here I go again....

    Thermionic devices don't like thermal cycling e.g switching them on and off

    If you leave a bulb on for 1 hour - it reduces its life by 1 hour - I think we can all agree on that

    If you switch it off and switch it on again 1 hour later you will have reduced the bulb life by X hours (where X is a variable from 0 to >>1 hour)

    So, you;ve the choice between a known reduction in bulb life over an unknown reduction in bulb life.

    There is no way to properly determine which is correct approach but having had years (nay decades) of experience with thermionic devices (large, expensive, transmitter valves) I go for the known reduction over the unknown

    My advice to my teachers (primary who use them most of day) is to turn the projector on when you want to start using it and only turn it off when they've finished using it for the day (or if PE last lesson - turn it off before lesson)

    I leave it up to them whether to turn off at lunchtime - some do - some don't - I only offer advice - I don't control them

    Unless someone actually runs proper tests with statistically valid numbers of projectors over several years then I don't think we'll ever know the true situtation.

    OF course, the latest variable is that the bulbs are a lot cheaper now (£150 instead of £300) so if you worked out the total cost then it might be cheaper to reduce the bulb life.

    But then the monies come from different budgets and ... and ... and ...

    Minefield

    Nobody is stupid for employing either policy and IMHO no-one knows who's right

    regards

    Simon
    PS and you really should leave fluorescent lights on

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    Re: do you keep projectors on all day?

    also, the gauze filters get bunged up quicker if they are on all the time, resulting in overheating/shorter bulb life etc.

    it's easy to forget about these but they get REALLY blocked with dust sometimes and can be a pain to reach if mounted 12 feet up in a studio/hall with a 25 ft ceiling etc - of course they get installed with the assumption that
    'someone' will clean the filters now and then .....

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    Re: do you keep projectors on all day?

    Quote Originally Posted by SimpleSi
    Thermionic devices don't like thermal cycling e.g switching them on and off
    But how many of us are still using CRT projectors? Very few I'd guess, the rest are using short-arc lamped LCD or DLPs.

    Our teachers don't use the projectors intensively, so I go for the "Off, unless you are going to use it" approach.

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    Re: do you keep projectors on all day?

    There is another aspect to leaving the projectors on all the time; the electronics get well & truly 'cooked'. We have had a significant number of projectors that have suffered significant image quality issues as a result of being left on all day, despite keeping their filters clean. In each case the small LCD matrix closest to the lamp has become discoloured, we suspect due to heat. We have had these problems with both Infocus and various models of Sanyo projectors.

    The economics of projector ownership is not straight forward; leave them on, prolong the lamp life & toast the electronics vs switch them off, shorten the lamp life but extend the projector life. As it is very difficult to obtain projector spare parts & having them regularly 'deep cleaned' or repaired by specialists is prohibitivly expensive I tried (& failed) to persuade staff to switch them off & preserve the projector life.

    We now have a rolling program of replacement; we are planning to replace up to 10 projectors (25% of our installed base) this year because of degraded image quality. Many of these are only 3 years old, & the real nuisance is of course that they are models which are no longer made, and the ceiling mounts don't fit the new ones so we are having to pay for new mounting plates & even move some mounts because of issues with distance and lens offsets.

    To our cost we discovered that even though many of our projectors came with a three year warranty they have in their small print 'or xxxx hours', which means you can easily reduce the warranty period by leaving them on all the time.

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    Re: do you keep projectors on all day?

    Quote Originally Posted by broc
    Many of these are only 3 years old, & the real nuisance is of course that they are models which are no longer made, and the ceiling mounts don't fit the new ones so we are having to pay for new mounting plates & even move some mounts because of issues with distance and lens offsets.
    Proper PITA isn't it? Try to ensure next time that the plates are universal (or at least semi-universal). The focal length issue is more of a problem, especially when you have to buy cheapest each time!

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    Re: do you keep projectors on all day?

    We follow the 'turn em off if you aren't using them' policy.

    One of the issues we all have to look at now is environmental damage caused by the school through IT. Reducing electricity usage in any way is a positive thing, even at the expense of a slightly shortened life span on the bulbs (which is yet to be shown, as we are replacing bulbs at the end of their 2500hr lifespan).

    Just make sure they don't just switch off the mains. Turn them off using the remote/on the projector itself.

    And regarding fluorescent tubes - Read http://www.consumerenergycenter.org/...nt_lights.html which has a full explanation of the urban myth.

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    webman's Avatar
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    Re: do you keep projectors on all day?

    We've found that with our oldest ones and degraded image quality - all they need is a good blowing out inside.

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    Re: do you keep projectors on all day?

    Quote Originally Posted by webman
    We've found that with our oldest ones and degraded image quality - all they need is a good blowing out inside.
    Strangely enough, that sentence could be applied to me , as well as to projectors

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    Re: do you keep projectors on all day?

    Quote Originally Posted by pinemarten
    also, the gauze filters get bunged up quicker if they are on all the time, resulting in overheating/shorter bulb life etc.

    it's easy to forget about these but they get REALLY blocked with dust sometimes and can be a pain to reach if mounted 12 feet up in a studio/hall with a 25 ft ceiling etc - of course they get installed with the assumption that
    'someone' will clean the filters now and then .....
    Don't mean to take this off topic, but how often DOES everyone clean the filters in their projectors? I have it easy compared to most, as I only look after about 26 projectors. For those of you with more, do you go around by yourself cleaning them all?

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    Re: do you keep projectors on all day?

    Quote Originally Posted by Jake
    Quote Originally Posted by webman
    We've found that with our oldest ones and degraded image quality - all they need is a good blowing out inside.
    Strangely enough, that sentence could be applied to me , as well as to projectors
    You're old and have bad eyesight? 8)



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