Hello. I am new to this post and would like some advice regarding my 13yr old Paddle GS3 that is plumbed in.

I purchased the gs3 new 13 yrs ago and have done some routine repairs as needed. My concern today is the brew pressure I am getting when I pull a shot has drifted up to 15bar!

When the machine has heated up my preferred temp of 198deg f, the pressure is 12 bar. When I move the paddle slowly to begin water flow , the pressure drops to 3 bar. When the pump comes as I begin to pull a shot the pressure moves up to 15bar! There is no leaking out the pressure release valve.

My set up is 18 gm of coffee for 25 seconds give me a 35 gm shot. And tastes good.

With no coffee in the bottomless portafilter the gauge reading is 12 bar when I opened the paddle and it drops to 9bar when when the water was running.

Any suggestions as to the cause?? Trouble shooting ideas??

I look forward to any help.

Paul

Barista1225 wrote:Any suggestions as to the cause?? Trouble shooting ideas??

I look forward to any help.

Hey Paul,

Welcome to HB!

I split your post into its own topic since it is separate from the other GS/3 topic.

Since your free flow pressure is 9 bar, but it spikes to 15 bar when brewing, I'd start by lower your brew pressure at the pump to read 9 bar when brewing. That will correct your brewing pressure, but I suspect you also have a worn gicleur which is leading to a much lower pressure during free flow.

To lower your brew pressure, remove the left side cover by first taking off the chrome beauty nuts on the side and then the 13mm half nuts securing the panel, if they are still there.

Once the panel is off, you can locate the pump, loosen the black plastic lock nut on the bypass valve and then turn the threaded relief valve stem counterclockwise to lower thevbrew pressure.

Feel free to post some pictures if you have specific questions. There are also a few good videos on YouTube showing how to adjust the brew pressure on your machine.

Cheers!

- Jake

Thank s For the quick response Jake.

I will lower the pump pressure during brewing to 9bar and see what happens.

Regards
Paul

Jake. I adjusted the pump pressure back to 9 bar. The flavor profile is back to where I like it!!!

A lot of espresso through the group head these past 13 years. You mentioned that the gigleur may be the problem. Is it time to replace it?

Thanks very much for your help.
Regards
Paul

Great news!
I'm happy to help.

What is your pressure in free flow now that you have 9 bar when pulling a shot?

Also, if you run the group wide open into a vessel for 10 seconds, how much water comes out?

Cheers!

- Jake

Jake.

The pressure is 9bar free flow.

10sec run gives me 80ml

Thoughts?

Paul

That seems like you are in good shape!

I'm a bit confused as to how your pressure was 9 bar before during free flow, but 15 bar when brewing and you lowered the pressure to 9 bar while brewing and the free flow pressure is still 9 bar. The only thing that makes sense to me is that your bypass plunger was stuck on the pump. In free flow, it was bypassing as designed and the pr3ssure was 9 bar, but when you put a puck in the flow, much more water needed to bypass in order for the pressure to remain at 9 bar, but the bypass was stuck and that didn't happen. By cracking the nut and adjusting the pressure, you freed up the stuck plunger and now everything is right as rain.

In either case, your numbers sound perfect, so I think you are good to go!

Cheers!

- Jake

Thanks for your expertise Jake. I'm thrilled just an adjustment was needed. I think your right about the bypass plunger. The pump sounds different with the adjustment. The pump had made a different sound when it began pumping into into the coffee puck pushing the pressure up. Now it's a consistent sound and a constant 9 bar pressure.

We just returned from italy and had some good coffee, but noted there was not much regard for dosing and tamping! Two doses from the grinder and a quick touch with the tamp!

Ciao
Paul