# Anyway to test/benchmark the Solenoid?



## Stu (Jan 3, 2018)

Hi all, I've had a used Gaggia classic (2005 model) since christmas and having gone through a full stripdown, service, descale and rebuild I'm now trying to work out if my solenoid is functioning fully.

I took the solenoid apart as part of the service and after recomissioning the machine and pulling a few shots, I noticed a small puddle of water around the pump/back of the machine internals. With help of a mirror, I could see it was the solenoid weeping out from where the brass 'post' screws into the brass bottom part.

Having trained as a plumber I decided to use PTFE tape to seal the brass connection which did stop the leak. Since then I've been wondering if the machine/solenoid is working as well as it should. I didn't notice any water coming out of the chrome pipe to the drip tray when killing the pump at the end of a shot pull and the puck was quite wet.

I decided to pull the solenoid back out and change the PTFE tape for a small o ring. This also sealed the unit and now when i pull a shot, I do get a small dribble out the pipe but nothing close to 1oz or so like I've read or seen on some people's technique videos. The puck is also still quite wet.

So now I'm wondering if there's anyway I can test the full (or not) functioning of the solenoid. Should there be an o ring anyway between the brass body bits? The solenoid itself isn't shown on the exploded diagram of the classic and the WholeLatteLove video showing the solenoid stripdown isnt clear enough to see the presence of an o ring. That video also says about lubricating the internal piston with food safe grease... I couldn't do this as didn't have food safe grease... would this help?

Any ideas and input appreciated!


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## ChiangMaiKevin (Dec 18, 2017)

Are you referring to this solenoid - That has two o rings?

http://thehippy.net/nucleus/media/1/20090122-gaggia_3way_valve.jpg

A rebuild kit would have had those o-rings...

http://thumbs2.ebaystatic.com/d/l225/m/mYLa-KJhezzHunMFa9KTJOw.jpg

I think you need a couple of these...

https://www.wholelattelove.com/o-ring-red-silicone-2025-c45c5085-6ffc-4e5c-892c-5bdcea5b5c15


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## Stu (Jan 3, 2018)

Here is what my solenoid looks like, with some added indications...

(Photo from espressoshop, hope that is ok)









The red dotted line shows where the two brass pieces separate and where I placed an o ring to seal the joint.

The blue rings show where I witnessed small drops of water weeping out of the join, hence needing some attention.


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## espressotechno (Apr 11, 2011)

If there was no o-ring present when you first opened the valve, then an o-ring isn't needed. Teflon tape will work well.


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## Stu (Jan 3, 2018)

Frank has sugested it is possibly a very thin teflon washer. I seem to recall there was a mangangled plasticy bit when I took it apart that I thought was calcified crust (as there was a lot of it!) Unfortunately that has long gone now and I can't guarantee it was sufficient anyway as the valve & boiler had clearly had a leak at some point woth lots of scale/black oxidisation.

This was a second-hand purchase so cannot guarantee any parts as being original.


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## Stu (Jan 3, 2018)

UPDATE: Now that I have some food safe grease, I've taken it all back apart, lubed up the central 'piston' and reassembled, this time back to using PTFE tape to seal the threads so that i can make sure the brass parts screw down to their full depth (so to speak.)

I pulled a test shot last night after this and still had a bit of a soupy puck after. The solenoid definitely works to some extent as it did discharge a small amount of water after killing the brew switch.

I do notice that when I have the steam switch on I often get a dribble of water from the grouphead and/or discharge pipe - is this normal?

Also last night whilst steaming milk, I noticed there was quite a few drips occuring out of the discharge pipe into the drip tray which seemed unusual - does this happen to anyone else? Is it normal? or is my solenoid actually not behaving very well?

Any help would be appreciated, thanks!


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