Fumehood Gas problems

[bigmack]

Hi all .
Used the Gas in our Fume hood yesterday for the first time .
Turned on the power. Fan and lights come on and pre-purge is done in a minate.....all very normal .

Press the Services button and the Gas Solenoid valve clunks on.
Turn the gas knob but the Bunsen , he no light .

Then try an hour latter and it lights and runs for several hours . Then I notice the flame has gone out .

so this morning , go to light it up again , but the same thing happens .....no gas .

Call the Work Dept and they laugh and say the gas bottle is empty . fair call

But then with a new gas bottle , still can't get the Bunsen to light , or any of the other two I tried ( that work in the Labs OK)

So do I have a dodgy Fumehood , or is there something quirky about this model that I'm not aware of ?

Fumehood.jpg

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Control panel.jpg

[Anna Z]

Maybe there is a safety cut out on it... will only let you run for a few hours... maybe after 2hrs go in turn it off and then on again. I don't know why...seems a bit silly. Ours are mains gas, so turn them on and their ON....

[RosalieL]

The draught created by our fume cupboard makes it really hard to get a good flame - it messes with the air/gas ratios. I hate that it has to be turned on to make anything work - like when you have to weigh something in a fume cupboard but the draught means you can't zero the balance.

[bigmack]

Maybe there is a safety cut out on it... will only let you run for a few hours... maybe after 2hrs go in turn it off and then on again. I don't know why...seems a bit silly.

That is quite possible Anna . I didn’t check to see if the Services on light had gone off .

The draught created by our fume cupboard makes it really hard to get a good flame - it messes with the air/gas ratios.

You’re not wrong Rosalie . It’s hard enough to get them to light at the best of times .
Alas I don’t have any other gas outlet in the Pre-rooms or Chem store . So forced to use the one in the Fumehood .
I was just boiling down several litres of CuSO4 so I don’t have so much hanging around . I wouldn’t trust setting it up in one of the labs .

I remember the gas outlet at my old school was a royal pain in the butt and we had so many contractors come to sort it out but in the end I think it ran for maybe 3 months in the whole 9 years I was there .
We’d have the fumehood tester come out . Then he would flag it as defective . Then the electrician would come out and say it was a gas issue . Then the plumber would come and say the gas was fine , it was an electrical problem .

So I’m reluctant to play this game again

[Anna Z]

Can you use a hot plate to boil off ?? still doesn't fix your gas problem though. FWIW I light my Bunsen outside the fume hood then duck it back in.

[Pm706Narrogin]

I remember the gas outlet at my old school was a royal pain in the butt and we had so many contractors come to sort it out but in the end I think it ran for maybe 3 months in the whole 9 years I was there

We've got an innovative solution to that at our school - it's called they never finished the fume hood when it was installed so we have no water or gas in ours.

We've got a plughole (complete with plug) ready to go. Only problem is there are no taps and the plughole leads nowhere. No gas either. In hindsight, I'm amazed they went to the trouble of hooking up the electricity for the fan cause everything else about the fume hood is just for show.

[bigmack]

What
Thats crazy
You’re DOE school . Don’t they come each year and test it .

[Pm706Narrogin]

We had our guy come in during Term 1 for its annual test and it passed. I don't know what he tests but presumably he's been passing it based on the fact the extraction works.

Even the Regional Technicians when they did their last comprehensive audit didn't mention it, merely marked it as not having water or gas and collected that data for designing future schools. They didn't actually make a comment or recommendation about having it properly plumbed and having a sink added

[Labbie]

WOW that is crazy

[bigmack]

Well I reported mine as still Nogo .The Works fella come around and after talking to the fume hood folk , started checking things and it seems there is no gas coming into the Gas shut off cock from outside . We are scratching our heads wondering how this main gas line which comes straight from the bottles to the preproom is blocked while the classrooms are getting gas .

Looks like the Gas fitters are scheduled to come look .

In the mean time , my CuSO₄ is slowly evaporating on an electric hotplate .

[bigmack]

Gas man come around . Climbed around in the roof and informed us that the adjacent Labs master gas shut-off cock needs to be on as well as the one next to the Fume hood .

Well don't we feel like fools .

It now explains why it randomly worked and then stopped . Teacher was turning on the Gas next door .

A big sign will now be fitted to the Fume hood

[Pm706Narrogin]

Wow that's a really inefficient system.

So if a teacher is using the gas in the next room and doesn't realise you're also using gas in the fume hood they could accidentally cut you off?

[bigmack]

Wow that's a really inefficient system.

So if a teacher is using the gas in the next room and doesn't realise you're also using gas in the fume hood they could accidentally cut you off?

Yup ,dumb , and I think that is exactly what happened on the day I was using it and realised after a few hours it was off . She had done the right thing and turned the gas off when she left the classroom .

I may have to hang a sign on the gas valve when I’m using it .

[Anna Z]

At least you have an answer now