# What am I doing wrong - Pressure test Gaggia Classic



## Chris 81 (Jan 4, 2018)

Hey members!

I'm trying to test the pressure of my Gaggia classic with a PF and pressure gauge. The Gaggia has already (supposedly) been set to 9bar. (Static or dynamic?)

So I thought it would be good to test for myself.

Going by the very helpful post on this forum I made sure to have done the following before testing.

- no basket in PF

- Add some water to PF/gauge

- open steam wand a bit after turning pump on.

I'll try to upload 2 videos to this post. But basically I read that opening the steam wand will help stop the needle vibrating and let air out for a more accurate reading, then as water comes out of wand instead of steam turn wand off.

But water comes out straight away as the steam switch is not on.?

First attempt:

When I turn pump on reading flicks all the way to full within 3 seconds,then clicks off and stops moving.

Second attempt:

I open steam wand for 6-7 seconds the pump stays on during this time then clicks off when I close wand back off. The Reading was around 4bar during this time then dropping to 2 bar pressure.

As I said I'll set up a youtube account later so I can add 2 video clips to this post, but in the mean time if anyone can understand my ramblings and has an idea of what I'm saying, all feedback appreciated !

Am I doing something wrong or is the pressure of my Gaggia around 2-4 bar? Some videos I've seen online all seem to have a similar pattern, my results seem different.

Thanks!


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## Chris 81 (Jan 4, 2018)

Update!

I tried testing with the steam open slightly before switching pump on. This gave me a slower, more accurate reading. Which unfortunately was around 4 bar!

Best get tinkering..


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## AndyDClements (Aug 29, 2016)

Are you closing the steam wand before attempting to take the pressure reading?

You'd be opening it to allow out the air that would otherwise be in the PF, but that air may still be in there for a short while (think about moving a pocket of air in the system and you need it to work its way out of the wand). Once the air is either out of the wand, or there's no chance of it coming out then you can close the steam valve.

All the time the steam valve is open, you're not measuring the maximum pressure of the pump/valve.


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## Chris 81 (Jan 4, 2018)

AndyDClements said:


> Are you closing the steam wand before attempting to take the pressure reading?
> 
> You'd be opening it to allow out the air that would otherwise be in the PF, but that air may still be in there for a short while (think about moving a pocket of air in the system and you need it to work its way out of the wand). Once the air is either out of the wand, or there's no chance of it coming out then you can close the steam valve.
> 
> All the time the steam valve is open, you're not measuring the maximum pressure of the pump/valve.


Thanks for the reply. So the last test that I mentioned in previous post was with the wand slightly open.

I thought that may be wrong!


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## haz_pro (Apr 4, 2013)

Wand needs to be shut completely.

I never open mine at all when testing pressure. Maybe I'm doing it wrong though!


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## ashcroc (Oct 28, 2016)

haz_pro said:


> Wand needs to be shut completely.
> 
> I never open mine at all when testing pressure. Maybe I'm doing it wrong though!


I didn't bother opening the steamwand when I set my OPV either. Just filling the basket to the brim through the brewgroup immediately prior to fitting did the trick.


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## Chris 81 (Jan 4, 2018)

ashcroc said:


> I didn't bother opening the steamwand when I set my OPV either. Just filling the basket to the brim through the brewgroup immediately prior to fitting did the trick.


This is what I did initially. But all that happened when I turned pump on was the dial going straight to maximum pressure reading then back down to zero and clicking off. That took about 3 seconds!


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## El carajillo (Mar 16, 2013)

Chris 81 said:


> This is what I did initially. But all that happened when I turned pump on was the dial going straight to maximum pressure reading then back down to zero and clicking off. That took about 3 seconds!


When you say "clicking off" What is clicking off ?








Te pump ?


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## Chris 81 (Jan 4, 2018)

El carajillo said:


> When you say "clicking off" What is clicking off ?
> 
> 
> 
> ...







By 'clicking off' I just mean pump sounds muffled almost like machine has stopped pumping water and goes 'off' but still actually on.

That video is by forum member Pirate. That is like what happens to my Gaggia during test


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## Chris 81 (Jan 4, 2018)

Seems like from an old post by Pirate it could be the OPV valve 'sticking' not sure how I'd go about un-sticking the valve but I'll have a look over the week end & hopefully be able to get an accurate reading.

The gaggia is actually pulling shots fine. Especially now I have the Macap Xtreme off Jon. He's a top bloke & that grinder is a tank! Needs a bit of a clean up and I've not dialled it in with my set up yet. But it's grinding fine enough to pull a decent shot already so maybe I don't need to be too concerned with the Reading? I just wanted to check it was actually pumping out pressure around 9bar.


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## Chris 81 (Jan 4, 2018)

Here is a clip of pressure test. Water in PF. Air/water let out of steam wand beforehand then turned back off. No basket.


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## Chris 81 (Jan 4, 2018)

Clip 2. Same as above except steam wand opened during test.


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## ashcroc (Oct 28, 2016)

Chris 81 said:


>


Think your OPV needs a bit of adjustment.


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## Chris 81 (Jan 4, 2018)

ashcroc said:


> Think your OPV needs a bit of adjustment.


How would I do that? Just take it out & give it a clean?

Or do you mean adjustment as in change pressure by screwing to left/right?

Thanks!


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## ashcroc (Oct 28, 2016)

Chris 81 said:


> How would I do that? Just take it out & give it a clean?
> 
> Or do you mean adjustment as in change pressure by screwing to left/right?
> 
> Thanks!


Change the pressure by screwing the allen key left. At the moment the guage is going off the scale so it's definately too high. You want to aim for it to kick in at about 10 bar static pressure to give you a 9 bar flow rate.


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## Chris 81 (Jan 4, 2018)

ashcroc said:


> Change the pressure by screwing the allen key left. At the moment the guage is going off the scale so it's definately too high. You want to aim for it to kick in at about 10 bar static pressure to give you a 9 bar flow rate.







Made no difference at all unfortunately. I turned key anti clockwise 1 full turn (Thinking a 1/4 turn more than the recommended 270° would do the trick)

Should I keep turning anti clockwise until I see a change on the gauge? I'm pretty sure the gauge isn't faulty as when I open the wand it moves through the dial nice & steady and holds around a certain level.

Sorry for all the questions & vids!

Cheers, Chris


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## AndyDClements (Aug 29, 2016)

What pressure range is the gauge?


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## Chris 81 (Jan 4, 2018)

AndyDClements said:


> What pressure range is the gauge?


12 bar/ 180 PSI at the maximum level of gauge


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## AndyDClements (Aug 29, 2016)

Oh well, just a thought.

In that case, I'd suspect that the OPV is stuck.As you've been adjusting it anyway, your'e part way to removing the necessary components so you may as well just pull it apart to ensure that it does actually move.


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## Chris 81 (Jan 4, 2018)

AndyDClements said:


> Oh well, just a thought.
> 
> In that case, I'd suspect that the OPV is stuck.As you've been adjusting it anyway, your'e part way to removing the necessary components so you may as well just pull it apart to ensure that it does actually move.


It is stuck now! I let machine cool a bit then unplugged and opened back up. Can't turn opv either way now lol I could give it a bit more welly but didn't want to break anything..


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## AndyDClements (Aug 29, 2016)

The moving part may well be hotter than the outside, so stuck by heat expansion. Let it cool more, and if necessary, take the whole thing into a pot of hot water for a short while, that way the outside cannot be cooler than the inside.


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## Chris 81 (Jan 4, 2018)

Still won't budge. Is the end suppose to look like that?


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## Chris 81 (Jan 4, 2018)

View attachment 31505


View attachment 31505


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## El carajillo (Mar 16, 2013)

I think you will find that is the "flare" which helps to make the plastic pipe grip / hold in conjunction with the nut.

If you have enough length on the plastic pipe, cut about 6 mm off the end to provide a new section to grip, also clean up the taper (fine wire wool etc)

Can you show a photo down to the adjuster ?


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## El carajillo (Mar 16, 2013)

As it is probably scale that has seized up the adjuster and the workings. Block up the pipe spigot (tapered bit) stand the OPV in a mug or dish then mix some descaler with hot water and fill the opv up OR just put it in a tall mug and fill it with descaler / leave over night. Then try again.


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## Chris 81 (Jan 4, 2018)

El carajillo said:


> I think you will find that is the "flare" which helps to make the plastic pipe grip / hold in conjunction with the nut.
> 
> If you have enough length on the plastic pipe, cut about 6 mm off the end to provide a new section to grip, also clean up the taper (fine wire wool etc)
> 
> Can you show a photo down to the adjuster ?


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## Chris 81 (Jan 4, 2018)

It looks dirty in pics but it's not actually that bad. I put a drop of olive oil in to help losen it up over night. Will try the descale tomorrow night.

As stupid as this may sound, I'm not even sure what is suppose to be turning when I put a 5mm hex inside?!

Apologies but I am new to all this


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## SimonN (Feb 4, 2016)

Chris 81 said:


> It looks dirty in pics but it's not actually that bad. I put a drop of olive oil in to help losen it up over night. Will try the descale tomorrow night.
> 
> As stupid as this may sound, I'm not even sure what is suppose to be turning when I put a 5mm hex inside?!
> 
> Apologies but I am new to all this


Are you sure the hex hex key isn't just slipping? It looks like it's rounded off and slipping from the picture.


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## Chris 81 (Jan 4, 2018)

SimonN said:


> Are you sure the hex hex key isn't just slipping? It looks like it's rounded off and slipping from the picture.


It's definitely a bit rounded, but still holds a grip. The hex key doesn't move at all.


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## AndyDClements (Aug 29, 2016)

I'm thinking, try and cut a slot where the hex hole is / should be (so that a wide screwdriver fits) and heat the outside with a blow-torch.


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## ashcroc (Oct 28, 2016)

AndyDClements said:


> I'm thinking, try and cut a slot where the hex hole is / should be (so that a wide screwdriver fits) and heat the outside with a blow-torch.


Hammering a similar sized torx bit can work on rounded hex heads. It pretty much kills the bit for normal use though.


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## Chris 81 (Jan 4, 2018)

I'm thinking maybe buy one of these?

https://www.gaggia-parts.co.uk/epages/es147467.mobile/en_GB/?ObjectPath=/Shops/es147467/Products/11012627


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## John Yossarian (Feb 2, 2016)

Hi Chris, I remember quite a few moons ago I had to do the OPV on my Fracino Heavenly. I disassembled it, descaled it and put it back. Everything was fine afterwards. In your case it looks like the OPV does not do much and as other have suggested see how you can bring it back to live. Another option would be just to get a new one, I do not know how expensive these are but I would be surprised if they are more than £20 (I will stand corrected should I be wrong). This is one of the exercise that make you a seasoned Coffee Forum member and once in the bag you will be a very proud problem solver







.

Good luck! And please keep posting the good results.


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## El carajillo (Mar 16, 2013)

Chris 81 said:


> It looks dirty in pics but it's not actually that bad. I put a drop of olive oil in to help losen it up over night. Will try the descale tomorrow night.
> 
> As stupid as this may sound, I'm not even sure what is suppose to be turning when I put a 5mm hex inside?!
> 
> Apologies but I am new to all this


That disc (about 4 mm thick) moves up and down as you turn it (SHOULD) that applies pressure to a spring holding down a seal.

When the pressure goes above a certain point it lifts the seal, compressing the spring allowing the excess water pressure to pass through the centre hole and return to the water tank via the tube.

By rotating the disc you are increasing OR decreasing the spring pressure on the seal which controls the brew pressure.

If you need a new OPV contact markgaggiamanual serve on the forum


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## Chris 81 (Jan 4, 2018)

El carajillo said:


> That disc (about 4 mm thick) moves up and down as you turn it (SHOULD) that applies pressure to a spring holding down a seal.
> 
> When the pressure goes above a certain point it lifts the seal, compressing the spring allowing the excess water pressure to pass through the centre hole and return to the water tank via the tube.
> 
> ...


Very helpful thank you


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