Ponte Vecchio Export: how is the pressurestat connected to the bottom plate [SOLVED]

Equipment doesn't work? Troubleshooting? If you're handy, members can help.

#1: Post by Remco »

HI Coffees,

I'm rebuilding my Ponte Vecchio Export (around 2015). I've no idea how the pressurestat is supposed to connect to the bottom plate. I don't see any screw thread. It looks like it was welded or soldered..? In that case i've destroyed it. Chances are I'll be drinking tea for the rest of my life... :shock:


#2: Post by JRising »

It looks like the hex fitting should be brazed in place, but someone didn't hold it securely when wrenching the p-stat out of it and it has broken free.
It's probably repairable if you can find someone you can trust, capable of working on boilers to braise it in place again. Alternatively, the hole could be tapped and the fitting on the p-stat could be replaced with something that threads in.

La Marzocco · Home: customized for espresso aficionados
Sponsored by La Marzocco · Home

#3: Post by Pressino »

The female connector that attaches to the plate looks soldered...you could try reattaching by silver brazing with one of lower temperature silver-bearing rods...(i.e. lower temperature than bronze rod brazing). :)

Remco (original poster)

#4: Post by Remco (original poster) »

@JRising That someone was me! I finally managed to separate the hex bolt, but the 'little pipe' inside is more or less stuck.

@Pressino, when 'brazing' do you use a solder iron or a flame?

Update: I managed to loosen the little pipe and it was pretty scaled...



#5: Post by Pressino »

Actually it may have broken off because the piece was originally soldered with something like ordinary plumber's solder (in fact that's exactly what it looks like in the picture), rather than brazed. Such solder joints melt at lower temperature than brazed joints, but for the usual temperatures and pressures you encounter in a coffee boiler it may have worked OK. If it were mine I'd clean up the copper pipe and boiler plate and silver braze the joint. You might be able to get away with plain soldering if you're able to do it. Otherwise take it to a shop to be done. Shouldn't cost too much.


#6: Post by Pressino »

Remco wrote: @Pressino, when 'brazing' do you use a solder iron or a flame?


You will need to use a flame to either solder or braze it...the critical part is getting the base hot enough to bind with the melted filler material (solder). An iron will not be able to supply the necessary heat. For something that size I'd use a Prestolite type air-acetylene torch for lead free plumbing solder, but to silver braze I'd use oxygen-acetylene with a small tip. Some folks find MAPP gas in a Turbotorch works as well. You need to get the soldered surfaces very clean and use an appropriate flux. With a good enough prep and well-fitting parts you may be able to get away with regular soldering.

Remco (original poster)

#7: Post by Remco (original poster) »

Ok good to know! I'll try to find someone with skills..

Baratza: skilled in the art of grinding
Sponsored by Baratza

#8: Post by Pressino »

I think you'll also need a new gasket when you reattach the plate to the boiler body after both are cleaned up. Assume you've got some sort of gasket.

Remco (original poster)

#9: Post by Remco (original poster) »

Instead of looking for someone with real skill, I realised that I could try something myself: heating the bottom plate, so the hole gets larger and I could stick the pipe inside.

I used a heat gun and a torch for creme brulee. The bottom plate was originally flush with the pipe, but now you can see it sticking out a little. I don't think this will ever come loose...


#10: Post by Pressino »

Looks like you actually melted the ring of solder that was visible on a previous photo. That's good, but it's hit or miss whether there was enough solder there to make a good joint. It might be OK as it is, but I think you'd be more certain by cleaning it up and applying flux and heating it up again while adding a bit of plumbing solder. Wouldn't be at all difficult to do. Just a suggestion. Others may want to chime in.