The machine is just 10 months old under my operation, so no need for the lubricants. The double-wrench technique was gold. I would have learned it through only one person within my entire social circle who's a mechanical engineer. Otherwise, none of my family and friends tinker around with much metal, so I'm greatful for your advice!

You guys are funny, all you have to do is hold the flow meter with another spanner. You see the flat part of the inlet and outlet, you can put an adjustable wrench right there. I have been repairing espresso machines for years and this is how I have always done it.

You guys are funny, all you have to do is hold the flow meter with another spanner.

Maybe yes and maybe no on both counts.

You, also, are missing the real problem this guy is experiencing. The tube adaptor fittings which are screwed into the flowmeter are sealed with a thread sealer/locker. Loosening those fittings may entail some extra work. The "backup" wrench should be on the adaptor's hex and NOT the flowmeter body.

The hex sizings on espresso machines is a jungle of inch/metric and sometimes an intentional compromise between those two. So, yes, sometimes a simple crescent wrench is the better choice for the tubing nut.

It is also helpful to use a tubing wrench. They give you 5 contact points on the fitting and help to prevent torquing the tube that you often get using an open end wrench which only gets you 2 contact points on the fitting.

HoldTheOnions wrote:You can also apply heat for a couple seconds to expand nut and try that. Heat too long though and fitting will expand too, defeating the exercise.

Heat and cold (heat nut and cold on tube) would be one method, BUT be careful about heat and penetrating oils. Flames are not the desired effect

A related question: is the 0.8mm giggler you are replacing with a 0.5 one - is it the giggler for the preinfusion - or is it the nozzle for the flowmeter. If it is the latter - it is very interesting to me if those are replaceable. Where do you buy replacements?

I always wanted to reduce the diameter of the nozzle on the gs/3 but didn't want to spend on a new flow meter.

It's after the flow meter so it's for a slower build up of pressure at the group.
Nuova Simonelli part number is 07300229 for 0.5mm gicleur. I forget what size they are, maybe M6 or M6. You can buy them from elektros.it.
Also Nuova Ricambi.de has LM gicleurs from 0.5mm to 0.8mm which are M4 size.

Ok. That is what I thought. If you want a smaller nozzle for the flow meter you must replace the flow meter body.

Thanks.