# OPV Adjustment



## StuartS (Jan 2, 2015)

Will i need to adjust my grinder after adjusting the OPV? I'm thinking lower pressure so coarser grind to keep the same flow but maybe this isn't the case. My normal tamp is "medium" - i guess around 20-25 lbs.

Also, i don't have a guage yet but I've read that 3/4 turn usually does the trick. I'd be happy to try say 1/2 turn and check for any improvement but only if i don't need to redial the grinder. Otherwise i'll do it once with a guage.

thanks

stuart


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## urbanbumpkin (Jan 30, 2013)

I'd wait till you get a gauge. Otherwise your just going to be doing twice.


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## StuartS (Jan 2, 2015)

Will i need to adjust the grind? The opv adjustment will take a few minutes but dialing in the ginder wil be much more time consuming.

thanks

stuart


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## colm1989 (Nov 17, 2014)

Yes, you will need to dial in your grinder again after adjusting your opv.


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## jeebsy (May 5, 2013)

It shouldn't too long to dial in your grinder either


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## StuartS (Jan 2, 2015)

Guage ordered with adapter, should arrive tomorrow so I'll have a go over the weekend hopefully.


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## StuartS (Jan 2, 2015)

I have just fitted the guage to my portafilter to see what pressure the machine is running at.

I start with the steam valve open, turn on the brew switch and then close in the steam valve to build the pressure. The pressure builds to aound 13 bar and then the pump appears to stop ( goes quiet). The pressure drops to around 10 bar and the pump starts again (pump noise comes back). Pressure goes back up and the pump goes off. It is cycling between 13 bar and 10 bar. It is cycling on/off every 2 secs or so. I thought it would just sit at a steady pressure according to the opv valve setting.

this behaviour is similar to what i get when the machine is choked.

is there something wrong somewhere - solenoid perhaps.

any advice welcome of course.

thanks

stuart


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## mremanxx (Dec 30, 2014)

I got a static pressure when I did mine, assuming the OPV works like regulators in hydraulic systems it should only dump the excess pressure and maintain what it has been set to. Have you dropped it to read 10 bar? If so what is it doing? You may just have a poorly seating regulator, it will basically be a spring holding a seated plunger and may be bypassing slightly. PM the gaggiaman if he doesn't respond, from what I've read he is a service engineer so will definetely know.


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## StuartS (Jan 2, 2015)

Update - tried with a backflush blank and it kept running. Tried again with pressure guage and it seemed to be running fine but the guage was moving rapidly between around 12 and 13.5 bar.

i then turned the opv 3/4 turn anti clockwise and now the pressure guage is moving rapidly between 10 and 11.5 bar.

is this normal - the guage needle is moving so fast it is blurred but i can see the upper and lower range clearly enough.


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## El carajillo (Mar 16, 2013)

The pump is vibratory which can give a slight gauge flicker, this can be exacerbated if there is any air in the gauge/PF or if there is any air in the boiler.

Check the gauge + PF are filled with water and run some water through the steam valve to ensure there is no air in the top of the boiler.


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## mremanxx (Dec 30, 2014)

I take it your gauge isn't glycerine filled? If not the needle will vibrate, gauges use glycerine as dampening. You will just need to try and guess it as near as damn it.


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## StuartS (Jan 2, 2015)

Initially i had filled the portafilter with water before fitting it - this gave me the problem i reported. I have just tried putting it on dry and closing in the steam valve after hitting the brew switch. The pressure rose steadily and the needle was stable at 11 bar (in the middle of where it had been vibrating).

I've now adjusted down to 10 bar with a steady guage so i'm sorted.

i had to grind finer with this lower pressure which is counter intuitive. Still need to grind a bit finer to get 1:2 ration in around 27s.

thanks

stuart


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