# Gaggia Classic OPV mod can be done without pressure gauge?



## JK009 (Apr 18, 2014)

Hi

Having read many threads about OPV mod, I found out 270 degree anti lock wise is for most of the cases

I think just turn the valve, then make a shot. Check the time, check to know how much coffee you have in 25-30second. Look at the coffee to check the cream, taste the flavour. Try and error....keep doing until you have good result.

Did anybody do the mod without pressure gauge? Succeed?

Thanks

JK


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## Hoffmonkey (Apr 28, 2014)

I did about 270 deg and then a bit more. Not sure you can be sure without a pressure gauge. I bought the bits for about 11 quid. There are people passing one around on the forum too. You'd only pay postage.


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## toString (Jun 18, 2014)

There's an easy portafilter version in the for sale forum at the moment too


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## froggystyle (Oct 30, 2013)

For the sake of £10 you are better off just picking up the three parts needed from Ebay...


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## NeilR (Oct 1, 2013)

I carried out the OPV mod without the gauge, probably turning about 225 degrees anti clockwise and I thought the coffee the produced tasted better than before the adjustment. I then got one of the gauges that was doing the rounds, which showed the pressure was 11 bar, so I turned it down a bit more. Therefore, a total of 270 degrees is going to be there or thereabouts. I guess, each machine will be slightly different and there will be a few variables when taking the pressure reading. Tasting the coffee is the key.


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## Neill (Jun 26, 2013)

I checked my pressure using the return from the opv and one of the charts available for pump info in the internet. It seemed to suggest the pressure was ok at the time. I then made my own gauge and it was high and needed reduced. I don't think I'd be keen on reducing without the gauge. If you turn it too low it'll cause problems.


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## JK009 (Apr 18, 2014)

toString said:


> There's an easy portafilter version in the for sale forum at the moment too


Thanks for your remind

i did make an offer . However, the seller was not interested. Now, he says " No offer" at all : £30

I think I should wait for " pass around gauge" from member here to pay the postage to borrow

With £30 in hand, I will pay

- £5 for delivery fee of passing

- £20 upgrade to VST or IMS baskets

- £5 for a bag of 250g Signature bean from RAVE


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## froggystyle (Oct 30, 2013)

I did have one, but i lent to another forum member some weeks ago, no sign of him now though!


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## El carajillo (Mar 16, 2013)

Adjusting by an angular adjustment is NOT accurate, you do not know what the pressure is running at in the first place therefore you have no idea what you have adjusted to.

I suggest you wait for the gauge which is being passed around, as this is really a one off adjustment there is no need to keep a gauge.


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## JK009 (Apr 18, 2014)

El carajillo said:


> Adjusting by an angular adjustment is NOT accurate, you do not know what the pressure is running at in the first place therefore you have no idea what you have adjusted to.
> 
> I suggest you wait for the gauge which is being passed around, as this is really a one off adjustment there is no need to keep a gauge.


Hi

thank for your advice.

You mean while the Gaggia is still in original, I should check the pressure first, then do the OPV mod after?

What will you advise me to do if the original pressure is:

1/ 11 bar

2/ 12 bar

3/ 14 bar

I saw the photo of the some pass-around gauge here only 11bar max


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## El carajillo (Mar 16, 2013)

The gauge needs to read up to at least 15 bar, any less and you could easily burst the gauge as when new Classic's are set to 15 bar.

As Classic's have vibration pumps which gradually ramp up the pressure it is normal to set to about 10 bar static (no flow through P/F) this then equates to approximately 9 bar when brewing coffee.


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## JK009 (Apr 18, 2014)

El carajillo said:


> The gauge needs to read up to at least 15 bar, any less and you could easily burst the gauge as when new Classic's are set to 15 bar.
> 
> As Classic's have vibration pumps which gradually ramp up the pressure it is normal to set to about 10 bar static (no flow through P/F) this then equates to approximately 9 bar when brewing coffee.


When looking at the photo in this link, I believe he turn the valve around 270 degree first , then fit the fit the ( PF + Gauge) after to check bar pressure

http://coffeeforums.co.uk/showthread.php?16407-Pressure-gauge-opv-for-Classic


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## JK009 (Apr 18, 2014)

El carajillo said:


> The gauge needs to read up to at least 15 bar, any less and you could easily burst the gauge as when new Classic's are set to 15 bar.
> 
> As Classic's have vibration pumps which gradually ramp up the pressure it is normal to set to about 10 bar static (no flow through P/F) this then equates to approximately 9 bar when brewing coffee.


How about this gauge:

http://coffeeforums.co.uk/showthread.php?16407-Pressure-gauge-opv-for-Classic


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## JK009 (Apr 18, 2014)

El carajillo said:


> The gauge needs to read up to at least 15 bar, any less and you could easily burst the gauge as when new Classic's are set to 15 bar.
> 
> As Classic's have vibration pumps which gradually ramp up the pressure it is normal to set to about 10 bar static (no flow through P/F) this then equates to approximately 9 bar when brewing coffee.


how about this gauge, it is only 11bar max?

http://coffeeforums.co.uk/showthread.php?16407-Pressure-gauge-opv-for-Classic


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## JK009 (Apr 18, 2014)

El carajillo said:


> The gauge needs to read up to at least 15 bar, any less and you could easily burst the gauge as when new Classic's are set to 15 bar.
> 
> As Classic's have vibration pumps which gradually ramp up the pressure it is normal to set to about 10 bar static (no flow through P/F) this then equates to approximately 9 bar when brewing coffee.


Hi

I have just received a pass-around pressure gauge . However, the max bar is around 13.8 bar. According to what you said, I have to adjust the valve first, before fitting the gauge. Is it true?


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## froggystyle (Oct 30, 2013)

open the OPV up and turn it half a turn and put it back together, then run the pressure test again and see what its reading, you may need to do the steps a couple of times to get it reading 10bar.


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## Kofe (May 4, 2014)

Just for reference and I know everyone's gaggia is diff. When I did mine it was reading 13.5 bar. So I turned counter clockwise 1 whole turn. And then another half a turn counterclockwise. Then clockwise 10 degrees. If that makes sense. : //


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## JK009 (Apr 18, 2014)

froggystyle said:


> open the OPV up and turn it half a turn and put it back together, then run the pressure test again and see what its reading, you may need to do the steps a couple of times to get it reading 10bar.


Please correct me if I am wrong:

1/ Open the Gaggia ( when it is cool) , open OPV, then half turn the valve

2/ Of course, fit all of them back.

3/Turn on Gaggia to warm it up ( without fitting PF+Gauge) for 15-20mins

4/ Attach the PF( no basket) + Gauge to the group head. ( Do I have to pour some water into the Gauge? How much?Or leave it empty)

5/ Press the pump on to check the pressure


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## Neill (Jun 26, 2013)

JK009 said:


> Please correct me if I am wrong:
> 
> 1/ Open the Gaggia ( when it is cool) , open OPV, then half turn the valve
> 
> ...


Yes, fill the pf with water, also bleed any remaining air from the system by running the pump with the steam knob open.


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## Kofe (May 4, 2014)

Someone more qualified than me will answer this. But yes fill portafilter with gauge. With water and attach it to group head. I also read somewhere just before you switch on machine. Purge steam wond. To make sure all air out of system.


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## El carajillo (Mar 16, 2013)

For the purpose of adjusting the OPV you do not need to heat it up. As Neill said fill the blind basket , run water through steam arm and brew head then fit PF. Operate brew switch untill gauge gives a steady reading (if it dances about it is usually because of air in system).

If adjustment is needed, switch off and unplug machine.Remove top cover if not already done, pull off OPV pipe and remove brass nut 17 mm I think ,insert Allen key and make adjustment (anti clock to reduce) (clockwise to increase). Fit brass nut finger tight ("O" ring under shoulder forms the seal) re fit pipe and retry pump.

Repeat the procedure until reading is approx 10 bar. RETIGHTEN BRASS NUT WITH SPANNER/SOCKET Refit pipe and replace top not forgetting the EARTH connection.


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## JK009 (Apr 18, 2014)

Neill said:


> Yes, fill the pf with water


please lemme know how much water ? Fill up nearly full of PF?


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## Neill (Jun 26, 2013)

JK009 said:


> please lemme know how much water ? Fill up nearly full of PF?


Yeah, full as it will go. I basically locked mine in while the pump was still running.


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## JK009 (Apr 18, 2014)

Neill said:


> Yeah, full as it will go. I basically locked mine in while the pump was still running.


I know priming by letting water coming out of the wand steam or the group head

you mean when water run through the group head, attach the PF in. Please tell me your reason of doing it

Thanks


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## Neill (Jun 26, 2013)

Basically you don't want any air in the group head as air is compressible and will affect the pressure reading. You need to top out the pf so that no air is contained. Lock it in place then run the pump with the steam knob open to flush any remaining air out.


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## JK009 (Apr 18, 2014)

Neill said:


> Basically you don't want any air in the group head as air is compressible and will affect the pressure reading. You need to top out the pf so that no air is contained. Lock it in place then run the pump with the steam knob open to flush any remaining air out.


Thanks for advice. Please read and correct me :

1/ Prime and warm up the machine (15-20mins)

2/ Fill the PF + Gauge full up water

3/ Turn on the switch pump

4/ when the water run through the group head, carefully attach the PF+ Gauge into the head ( do not let any water in PF come out)

5/ Lock the PF +Gauge in the head

6/ Switch the pump on. As the pressure rises open the steam valve a little, this will hopefully allow any remaining air out of the system. Once having a steady stream of water from the steam wand close it and allow the pressure to build until it settle


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## urbanbumpkin (Jan 30, 2013)

I didn't let my machine warm up when I did mine. I don't think you need to when adjusting the OPV.

It will make the OPV valve hot to handle that your going to be adjusting.


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## jeebsy (May 5, 2013)

http://coffeeforums.co.uk/showthread.php?3859-Adjusting-the-OPV-(over-Pressure-Valve)-Gaggia-Classic


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## Neill (Jun 26, 2013)

Sounds fine but you don't need to heat the machine up, in fact, don't as you need to handle the innards to do the mod. Also don't worry about some water spilling from the pf, it's going to happen.


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## jeebsy (May 5, 2013)

I've got a post in moderation - I'd do it warm. Opv valve will be easier to use and you want it operating under normal conditions


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## El carajillo (Mar 16, 2013)

jeebsy said:


> I've got a post in moderation - I'd do it warm. Opv valve will be easier to use and you want it operating under normal conditions


It does not need to be warm /hot as you are only adjusting to release excess pressure from the pump above what you require for brewing coffee.

The components get hot very quickly without providing any benefit or variation to pressure setting.


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## froggystyle (Oct 30, 2013)

I didnt warm up mine, it gets hot quickly.

4/ when the water run through the group head, carefully attach the PF+ Gauge into the head ( do not let any water in PF come out)

Didnt do this step either.

Thinking now i should check mine again, if i ever get the kit back!


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## JK009 (Apr 18, 2014)

First test. My Gaggia pressure is. 12.2 bar ( factory setting)

a bit confused. I read some one said 14 bar. The other said 12-12.5 bar

what is your Gaggia pressure?


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## Kofe (May 4, 2014)

Mine was 13.5 bar before. 10 Bar ish now.


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## froggystyle (Oct 30, 2013)

Dont worry about what it is, just get it to what it should be.


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## JK009 (Apr 18, 2014)

Having check carefully, I found that my new model Gaggia Classic's factory preset pressure was at 12 bar

I read a lot OPV threads before turn the valve. I decided to turn exactly 270 degree. Luckily, Just only one try, I had mine set to 10 bar

Reading the pressure when the machine is cool, the needle of the gauge vibrated not much. So I can read it easily 10bar max.

However, leave the Gaggia warm for 20mins, then check again the needle of the gauge vibrated too much. I could see that it was around 10 bar, but very difficult to read!

There is something wrong?


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## JK009 (Apr 18, 2014)

The 1st photo: the Gaggia before turning

The 2nd photo is after turn


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## Wilko 4473 (Dec 27, 2018)

So I've just stripped my classic. Don't think it had ever been done. I've ordered s complete set of seals, brass shower plate and screen. Once I've got it rebuilt I'd like to adjust the opv before doing some of the other rmods. Is the opv pressure gauge that was being handed around the forums available still? If so I'd love to have it so I can get mine set.


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## ashcroc (Oct 28, 2016)

Wilko 4473 said:


> So I've just stripped my classic. Don't think it had ever been done. I've ordered s complete set of seals, brass shower plate and screen. Once I've got it rebuilt I'd like to adjust the opv before doing some of the other rmods. Is the opv pressure gauge that was being handed around the forums available still? If so I'd love to have it so I can get mine set.


Put your name down on the list on this thread & it'll get to you eventually.


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