do you keep projectors on all day?

[chrbb]

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?

[webman]

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

[john]

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.

[webman]

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

[john]

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

[SimpleSi]

@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

[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 .....

[Andrew_C]

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.

[broc]

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.

[Andrew_C]

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!

[localzuk]

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/myths/fluorescent_lights.html which has a full explanation of the urban myth.

[webman]

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

[Jake]

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

[_Bat_]

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?

[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)

[Jake]

Indeed..and the odd blowing out doesnt hurt

[SimpleSi]

@localzuk

For example, turning off an F40 fluorescent lamp for only one-half hour a day can save about $4.00 (based on 8 cents/kWh) in energy over the life of the lamp. In fact, the money saved by this routine is typically more than the price of a new lamp.

 

Even an enviromental, lets save the planet, no doubt vegetarian eater with the wind behind them, living in California eco land can only bring themselves to say the money saved is "typically" more then the price of a new lamp

 

@Andrew_C

the rest are using short-arc lamped LCD or DLPs.

 

All the projectors we've got up here have got have a lamp that gets hot and emits light and is cooled by a fan- I look forward to seeing one of these new ones

 

regards

Simon

[bishopsgarthstockton]

We ask the teachers to switch leave on during, when not in use to just 'no show' the projectors and when there done at the end of the day to just switch off

[MkII]

Our installers across Wales when each school was given a couple of projectors and interactive whiteboards, we were left instructional laminates to turn off the projectors to save lamp life.

[localzuk]

Even an enviromental, lets save the planet, no doubt vegetarian eater with the wind behind them, living in California eco land can only bring themselves to say the money saved is "typically" more then the price of a new lamp

 

How expensive are your fluorescent tubes? They are about £2 each are they not? How long would you say the life of such a tube is? 3 years average? At 9p a unit for electricity, a 36W lamp costs ~£17 to run for 3 years for 9 hours a day. The saving of turning one off for half an hour a day would be 90p. So, yes the saving wouldn't quite be the cost of a new bulb but spread that across the 4 - 6 bulbs per class room multiplied by classroom and you have a significant saving - in our school that would be £157 over 3 years (aka 1400kWh's of power). I think our bursar likes that kind of saving, especially as it costs absolutely nothing to implement.

 

And also take into consideration that if they are turned off during breaktimes and lunchtimes, the 'half an hour' should be turned into an hour and a half really. So you can multiply that by 3.

 

Combine this with turning computers off when they aren't being used, ensuring heating isn't on when the windows are open etc... and the cost savings are considerable.

[DMcCoy]

Hmm, I think my server room is using around 87360kWh a year. Can I turn those off?

[cooper]

I have put all the projectors on to low power, this saves bulb life and uses less power. The only draw back is the image isnt as bright, but the fan i quieter

[Andrew_C]

@Andrew_C All the projectors we've got up here have got have a lamp that gets hot and emits light and is cooled by a fan- I look forward to seeing one of these new ones

As I remember it thermionic refers to the emission of electrons from a hot cathode. In televisions and Barco projectors,those electrons are guided down a tube where they strike phosphors which in turn give us light. The elements in these may well not like repeated heating and cooling, just like valves didn't.

 

A short-arc is fundamentally different, even if it does get hot as a secondary effect. Oh, &btw I do understand that heat=light.

[localzuk]

Hmm, I think my server room is using around 87360kWh a year. Can I turn those off?

 

I've actually been considering doing this. Turning our 6 servers off for even 2 hours would save us a large sum of money each year.

[Sylv3r]

Personally I prefer teachers here to turn them off when not in use, as I feel if they are not using it lesson 5 (last lesson of the day) they are less likely to leave them on, when they leave school at the end of the day. Its generally the same people all the time, but thankfully the cleaners are generally flexible and will turn the projecotor off if the teacher is no longer in school. Via the correct route with the remote also - not just with the on / off switch at the wall (we use a key switch in most rooms so its not possible anyway).

 

It appears that the only projectors here are more 'heavy duty' and the bulbs appear to have lasted for ages - I dont remember ever changing one particular projector bulb and it must be over 7 years of age and still going strong.

 

However the projectors that have only been put in 2 or 3 years ago have possibly had a new bulb installed.

 

In september we will be looking at having around 65 - 85 installed projectors across the school and at present the job of cleaning the filters is not done reguarly enough - once a half term, I will be looking at putting together a program where we try to clean each projector on a 3 - 4 week basis.