# Classic Problem



## m4lcs67 (Mar 16, 2014)

Hey folks,

Have just made a coffee this morning and I have noticed that when I switch the pump off there isn't a release of water down the venting pipe into the tray at the bottom that there should be. Can't remember it happening before, but I have recently done the opv mod. I don't know if that is something to do with it, or is there another problem?

Thanks for any advice


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## oracleoftruth (Jan 15, 2014)

Do you have a blank backflushing basket? Worth trying that.


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## froggystyle (Oct 30, 2013)

Mine does that everytime Malc, think its just a release of pressure from the head as the water is dirty it doesnt really want to go back into the clean water....


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## coffeechap (Apr 5, 2012)

there is or there isnt a release?


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## froggystyle (Oct 30, 2013)

ahh i read that wrong, mine does it still after the OPV mod.


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## m4lcs67 (Mar 16, 2014)

There isn't a release of pressure as there used to be.


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## m4lcs67 (Mar 16, 2014)

Great idea, Oracle. I have just put my blank basket in and set it going and when I switched the pump off it did shoot some water down the venting pipe albeit at a reduced velocity.

I then put my normal basket back in tried it again and the problem persists. Nothing out of the venting pipe. Obviously there must be a problem, but I am at a loss to think what it could be.


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## froggystyle (Oct 30, 2013)

Malc, Have you changed anything since the last time you noticed it, took the plate off? Messed with anything inside? changed the baskets? changed your portafilter?


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## m4lcs67 (Mar 16, 2014)

Hey Froggy,

Nothing that springs to mind. Have just backflushed it with water using my blank disk and it did force some water down the venting pipe, but at the reduced pressure. Don't know if there is a blockage somewhere?


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## froggystyle (Oct 30, 2013)

Hmm maybe, how are the shots tasting, any big difference? are you seing any difference in the puck when removing?


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## The Systemic Kid (Nov 23, 2012)

Malc - your OP mentions making your morning coffee - was it any different to other shots - i.e. was it OK? Also, when you removed the portafilter was there anything unusual about the puck - was it soggy or relatively dry.


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## m4lcs67 (Mar 16, 2014)

To be honest everything does seem ok. I have started recently having my coffee ground, by my local coffee shop until I can get my grinder sorted, but surely that wouldn't cause the machine to block as the water is going out via the portafilter and not into the machine?


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## m4lcs67 (Mar 16, 2014)

The puck was dryish. Certainly more dry than it has been in the past.


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## The Systemic Kid (Nov 23, 2012)

If everything seems OK - shouldn't worry. Purpose of the vent is to release excess pressure so you can remove the portafilter without getting splattered.


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## The Systemic Kid (Nov 23, 2012)

Just as a matter of interest - how much are you dosing and what weight are your extractions? How long is an extraction taking?


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## m4lcs67 (Mar 16, 2014)

That's a relief. I was a little worried that there might be a problem with the pump or something. I am putting in 15g of coffee and getting around 24-26 liquid out in around 23-26 seconds at the mo. Once I have my own grinder I will be able to tinker with the grind, but for now I am kinda stuck with it, although it isn't a million miles away.


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## froggystyle (Oct 30, 2013)

m4lcs67 said:


> The puck was dryish. Certainly more dry than it has been in the past.


And these shots took the same time, weighed and taste the same as before?


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## m4lcs67 (Mar 16, 2014)

Yeah, pretty much. Obviously it a pressure release valve, so my first thought was is there a problem with the pump internals that is causing it to not vent anymore????? I have a Gaggia service centre just a few miles from where I live, so If there was something seriously wrong I could have got them to take a look, but that costs money and my first port of call was the forum to see if anybody could shed some light on what could be wrong. Maybe a full on backflush with some Caviza might do the trick. In the past I have also used the bottled Gaggia cleaner (the stuff that goes in the watertank), but would it be advisable to dilute some Caviza with water and pass it through the whole system???? I know the boiler is only made of aluminium and the Caviza is quite heavy duty, so I don't want to damage the internals.


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## froggystyle (Oct 30, 2013)

When did you start using a new batch of coffee, before you noticed the change or after?


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## m4lcs67 (Mar 16, 2014)

I got some yesterday. I got them to grind it a little finder this time as the last batch gushed a little. This lot came out pretty much spot on in terms of weight in, weight out and time. I'll try some different coffee and see if that makes a difference.


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## froggystyle (Oct 30, 2013)

I dont know a lot about my gaggia just yet, but maybe if the grind is right you get less back pressure!?


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## m4lcs67 (Mar 16, 2014)

Yeah I think you could be right. Also thinking about it might be a contributory factor switching to standard non pressurised baskets and the opv mod as there won't be as much back pressure to divert down the vent pipe?


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## froggystyle (Oct 30, 2013)

I have only used the non pressurised baskets, so cant comment on that part. But the OPV mod, i have not noted any difference since doing it, but then i have dumped my drip tray and now use a piece of hose from the pipe to the sink....


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