# OPV has made things worse!



## jmc (Sep 13, 2013)

Hi all, bit of a newbie so my apologies if these are stupid questions.

Just bought a new Classic from SimonB which I'm very happy with (thanks Simon!)

I'm using a bottomless portafilter and the first few shots I poured were great. I don't have any photos but there was a good amount of crema, the flow from the portafilter was excellent and most importantly it tasted great. The only criticism was that it might have poured a bit fast (15 seconds).

I since did the OPV mod (just by turning 270 deg, not by measuring the actual pressure) and I've since found that the flow from the portafilter is pretty inconsistent - it takes longer for the coffee to begin to pour after hitting the button, there are often two streams etc. It still tastes pretty good but there's next to no crema now.

Obviously the simple solution would be to undo the OPV mod but so many people swear by it, I'm wondering if I'm dong something else wrong. I haven't changed the beans/grind but I have since bought a proper tamper, so perhaps I'm now tamping too hard?

Any tips/advice would be much aprpeciated - thanks!


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## The Systemic Kid (Nov 23, 2012)

You can't adjust the OPV blind - if you're going to do it, you need portafilter with gauge to set it accurately to 10bar.


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## Neill (Jun 26, 2013)

jmc said:


> Hi all, bit of a newbie so my apologies if these are stupid questions.
> 
> Just bought a new Classic from SimonB which I'm very happy with (thanks Simon!)
> 
> ...


Where are you based?


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## jmc (Sep 13, 2013)

Ah I'd read a few things that suggested a blind adjustment, while not as exact, would be "good enough".


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## jmc (Sep 13, 2013)

I'm in London SE1


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## Neill (Jun 26, 2013)

jmc said:


> I'm in London SE1


I have a pressure meter you can screw on to your standard basket if you take the spouts off. It's currently with my brother in Leyland. I could see if he could post it to you. They are pretty cheap to buy the parts for.


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## jeebsy (May 5, 2013)

I've got a gauge you can borrow too if you can get the spout off your portafilter. There's a way to do it without a gauge by measuring flow out one of the outlet pipes or something which might help in the meantime. Look it up.


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## El carajillo (Mar 16, 2013)

I have tried the flow measuring to compare with using a gauge and checking against ULKA pumps flow rate charts.I found it to be VERY inconsistent and in accurate.

For a temporary correction for jmc I would suggest turning back half previous adjustment, as it sounds as if pressure is too low.


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## jmc (Sep 13, 2013)

Thanks all! What do you mean by the spouts? It's a bottomless portafilter so there aren't any spouts? Or are you referring to something else?


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## Mrboots2u (May 10, 2013)

jmc said:


> Thanks all! What do you mean by the spouts? It's a bottomless portafilter so there aren't any spouts? Or are you referring to something else?


Do you have a standard portafilter too?


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## jmc (Sep 13, 2013)

Mrboots2u said:


> Do you have a standard portafilter too?


Yep got a standard one too


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## Mrboots2u (May 10, 2013)

jmc said:


> Yep got a standard one too


Then that will have the spouts on it . The spouts are the things the coffee comes out of ( will either be a double or single spout ). The spout itself is normally attached by a screw fittings. If you can get this out you can attache the pressure gauge to it people refer to. Unscrewing it may take a bit of elbow grease and possibly heating the spout bit if you can't shift it straight off.


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## El carajillo (Mar 16, 2013)

You need a standard P/F with a threaded section on the underside where you can screw on a two way spout used to fill two cups at once.You remove the spout and screw on the gauge in its place. Look online for OPV mod in a vid to see how it is done !!

On some P/F the spout seems to be locked on with adhesive it can be quite tight to remove but they do unscrew.


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## Mrboots2u (May 10, 2013)

I'm guessing but Neil is referring to something similar like this then being screwed onto where the spouts were...


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## jmc (Sep 13, 2013)

Got it, that makes sense, thanks everyone. Neill, that'd be great if I could borrow a gauge, much appreciated. El carajillo, I'll turn it back 180 in the meantime and see how that goes. Cheers!


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## Neill (Jun 26, 2013)

jmc said:


> Got it, that makes sense, thanks everyone. Neill, that'd be great if I could borrow a gauge, much appreciated. El carajillo, I'll turn it back 180 in the meantime and see how that goes. Cheers!


Right my brother is currently loaning it to another forum member but I'll try and egg it posted on for you once he's got it again. To use it get your standard portafilter and unscrew the spouts from the bottom. I did this by putting a screw driver through the hole on one side of the spouts and out the other. It only moved a bit so I stuck the spouts in boiling water for a while then it screwed off. Once off put a bit of ptfe tape around the threads and screw the gauge on. Take the basket out of your pf, fill with water and lock in to your machine. Purge any remaining air from the system by opening the steam valve whilst the brew button is on then close it off. The pressure your aiming for is 10bar as this is static so should work out around 9 bar if coffee is flowing. Pm me your address and I'll let you know when u can get if posted on.


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## jeebsy (May 5, 2013)

If you can get the spouts off I've got one you can borrow now.


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## Neill (Jun 26, 2013)

jeebsy said:


> If you can get the spouts off I've got one you can borrow now.


That'll work as mine may be in use for another week.


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## narc (Apr 25, 2013)

You can't just change the pressure and not have it affect the other variables in the extraction. After changing the pressure you will have to start from scratch re: dialling it in. I have a pressure gauge and the OPV adjustment is very sensitive, a small turn can change it by 0.5bar - measure the pressure and start again with dialling in your grind etc.


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## gaggiamanualservice.com (Dec 22, 2009)

why alter it, the pressure is set for a reason. if you alter the opv WRONGLY, machine broken and cost more to fix than you paid

make small mods, but DONT damage it because other people say its ok.

when I worked for gaggia, the Italians told to NEVER recommend back flush as it overloads the pump and fails the solenoid

people still do it !!!!!!!


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## Neill (Jun 26, 2013)

gaggiamanualservice.com said:


> why alter it, the pressure is set for a reason. if you alter the opv WRONGLY, machine broken and cost more to fix than you paid
> 
> make small mods, but DONT damage it because other people say its ok.
> 
> ...


But is the pressure on newer gaggias not set higher to allow for use of the pressurised baskets or pods? I thought the older machines ran at a lower pressure without modification


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## urbanbumpkin (Jan 30, 2013)

Neill said:


> But is the pressure on newer gaggias not set higher to allow for use of the pressurised baskets or pods? I thought the older machines ran at a lower pressure without modification


That was my understanding too


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## urbanbumpkin (Jan 30, 2013)

gaggiamanualservice.com said:


> why alter it, the pressure is set for a reason. if you alter the opv WRONGLY, machine broken and cost more to fix than you paid
> 
> make small mods, but DONT damage it because other people say its ok.
> 
> ...


Sorry if this is going off topic. But on the same note, how do you clean the machine if you don't back flush?


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## El carajillo (Mar 16, 2013)

Remove the shower screen and the block behind it , soak them in puly cafe.Clean inside the head with some P/C on a cloth or use a tooth brush.This is where the coffe residue collects.


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## urbanbumpkin (Jan 30, 2013)

El carajillo said:


> Remove the shower screen and the block behind it , soak them in puly cafe.Clean inside the head with some P/C on a cloth or use a tooth brush.This is where the coffe residue collects.


Thanks for the reply. The last couple of times I've done a back flush I've removed the block anyway, so this could be an option.

Does back flushing not clean anything else?


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## Glenn (Jun 14, 2008)

I still advocate backflushing the Gaggia Classic

My machine never failed once in over 8 years

Never let the pump labour, that will cause it to fail prematurely


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## Milanski (Oct 10, 2013)

Makes sense...

However, would be interesting to know what the oldest machine on here is that has been regularly backflushed.

I've only had mine a few months (so Phillips) and I backflush after every use and every three/four weeks with Full Circle.


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## jmc (Sep 13, 2013)

jeebsy said:


> If you can get the spouts off I've got one you can borrow now.


Thanks very much, I'll check to see if I can get the spouts off when I get back tonight.



Neill said:


> Right my brother is currently loaning it to another forum member but I'll try and egg it posted on for you once he's got it again. To use it get your standard portafilter and unscrew the spouts from the bottom. I did this by putting a screw driver through the hole on one side of the spouts and out the other. It only moved a bit so I stuck the spouts in boiling water for a while then it screwed off. Once off put a bit of ptfe tape around the threads and screw the gauge on. Take the basket out of your pf, fill with water and lock in to your machine. Purge any remaining air from the system by opening the steam valve whilst the brew button is on then close it off. The pressure your aiming for is 10bar as this is static so should work out around 9 bar if coffee is flowing. Pm me your address and I'll let you know when u can get if posted on.


Thanks very much for the offer Neill!


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## xiuxiuejar (Jan 24, 2012)

The OPV is just a valve which opens when the pressure hits a certain level so in theory reducing it shoul have no detrimental effect as the pump should be working with less pressure. As for backflushing, as long as you don't sit there for 30 or 40 seconds, I can't see it being bad for the machine - again, as long as you turn the pump off when the noise changes. I backflush almost daily and have never had a problem.


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## jmc (Sep 13, 2013)

urbanbumpkin said:


> Sorry if this is going off topic. But on the same note, how do you clean the machine if you don't back flush?


I came across this guide to dissasembly and cleaning when I was troubleshooting my machine: http://protofusion.org/wordpress/2012/04/gaggia-classic-disassembly-and-cleaning/

UPDATE:

Did a pretty thorough clean and descale and that seems to have improved things a lot. I can now at least get shots with decent crema, so perhaps it was just in need of a clean all along. That said, I'll try the OPV mod with a pressure gauge and see if I get the same problems, but it seems like it just needed a bit of TLC.

Thanks for all the advice everyone!


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## urbanbumpkin (Jan 30, 2013)

I used the longest thickest screwdriver / metal bar that I could fit through both spouts and used the leverage to undo the thread. I did leave the head of the PF in boiling water for 5 mins before trying it.

So wrap in a tea towel too.


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## xiuxiuejar (Jan 24, 2012)

jmc said:


> I came across this guide to dissasembly and cleaning when I was troubleshooting my machine: http://protofusion.org/wordpress/2012/04/gaggia-classic-disassembly-and-cleaning/
> 
> UPDATE:
> 
> ...


Don't use citric acid to clean the Gaggia. Get either the Gaggia/Saeco/Philips bottle cleaner or Puly Baby. Aluminium boilers are perfectly safe until they are treated incorrectlly!


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## jmc (Sep 13, 2013)

I used Puly Baby so hopefully no problems!


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