Carimali Lever Boiler Repair Question

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RKRobinson
Posts: 33
Joined: 2 years ago

#1: Post by RKRobinson »

Im now working on this Carimali and after cleaning the boiler have discovered a leak that the previous owner couldnt fix. In one of the lever brackets, the dipper pipe seems to have a bad solder. Ive poured water in from the group side and it doesnt go through the dipper as it should, instead it flows into the boiler around the dipper pipe. As I cant fully see the joint Im not sure how to fix it. Is it possible to remove the nut without damaging the boiler and repair it? Should I just try to add some silver solder to the joint and see if that seals it? Anybody know of schematic that shows this joint? This view shows how the joint works though the leaking one is in the back (of course). with a view from the top The previous owner I dont think opened up the boiler and didnt understand where the leak was coming from. The solder on top doesnt seem to serve any purpose.

This is how the solder looks. Pretty much like the other one. No obvious cracks.
This how they look together.
Its a nice machine but the previous owner tried a number of ill advised repairs to fix this problem that made the boiler a mess. Im hoping to avoid that.

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dmccallum
Posts: 136
Joined: 11 years ago

#2: Post by dmccallum »

Hello Richard,

Just to clarify, you say when water is poured through the external grouphead feed hole that:
1) no water flows back down the feed pipe (Suggesting a complete blockage?), and
2) water does flow into the boiler but via the feed pipe to boiler joint (Only via this route? At what rate? Freely or just a little?)

Some of my thoughts and approach.

Assuming a crack in the feed pipe joint: I don't think silver solder is an option here. You'd have to heat the joint to 650degC for any silver brazing work and given the size of the boiler and fact that it's copper, you'd need a tremendous heat source capacity to get it to that. There's also the fact that you may not get the surfaces clean enough for the braze to take, and there's also a larger risk of damage to other parts of the boiler given it's size than I'd be comfortable with.
There's another approach that may be applicable and it assumes the crack is small. Anearobic sealants are the penultimate solution for boiler cracks when brazing is not practical/possible. Anaerobic sealants/adhesives cure on contact with metal and in the absence of air. The product therefore cures between the mating threads, while the escaping product stays liquid. A small bottle of Loctite 290 is what you'd need. I've used it several times on boiler leaks - heat the piece to dry the joint and while still warm apply to the crack. It wicks but I also try to encourage it into the joint applying a small suction on the other side.

On the feed pipe blockage. That sounds a bit odd if it is completely blocked. Does that big nut on top act as a tap for servicing purposes I wonder? I'd be reluctant to move it regardless, and if I did explore this I would certainly bolt the flange to a substantial metal bar to leverage on rather than the boiler casing and use a good ring-spanner. Careful application of heat may help it on its way.
Otherwise strong citric acid solutions fed into the feed pipe way unblock it (that would be a long process of fill/empty/fill... given the small volume of solution, but you'll get there. Heat the thing to speed this process up). A fish tank pump with silicon tube if you have one can be useful to flow active acid solutions over parts in tight spaces.
I'd go through the citric-acid clean process first. It should clear your blockage, and clearing any scale will likely help with that top nut disassembly should you go down that route.

Good luck!
Derek

grinser
Posts: 33
Joined: 1 year ago

#3: Post by grinser »

Without knowing the machine, it looks to me like the nut on top could be connected to the dipper tubes, and the dipper tubes could be removed if the nut is opened.

In the boiler it does not look like the dipper tube is soldered to the group connector. Maybe there is an seal between the tube and the group connector wich failed...

RKRobinson (original poster)
Posts: 33
Joined: 2 years ago

#4: Post by RKRobinson (original poster) »

Thanks Derek and Grinser, The feed pipe is not clogged. But when I block the dipper tube and blow through the port of the group there is a detectable small leak (there is no similar leak on the other dipper). The group probably wasn't filling with water properly (if at all) and getting a lot of steam. Derek Ill take your recommendation and try the lock tite. Before I saw your response I did try silver plumbing solder with no success. I thought I could treat it like a regular copper pipe joint and sweat the joint but your right I couldn't get it to the right temp. Now after cleaning my mess Ill go out and get some lock tite. Im able to see the joint a bit better with a mirror. Its a strange and difficult design. Not at all like my gaggia where the dipper just bolts onto the group. I suspect its prone to blockage if not cleaned regularly. Ill leave the stuck bolt for now.

RKRobinson (original poster)
Posts: 33
Joined: 2 years ago

#5: Post by RKRobinson (original poster) »

Here's some better pictures. My dilemma is that I cant see the leak. When I pour water into the spout it comes out somewhere below the pipe that I can see. What I thought was solder seems to be brazed and appears fine. I have been able to get silver pumbers solder to stick and I might just see it I can seal the leak by putting solder in the gap around the brass fitting that holds the dipper. Or possibly jb weld. I think Id have to use too much lock tite.

Should I go back to working on the bolt to see if I can gain access that way? Its a real conundrum.

grinser
Posts: 33
Joined: 1 year ago

#6: Post by grinser »

If it was my machine, i would definetly ipen the big nut and see what it does. For me, the joint between the dipper tube and the group connecting piece inside the boiler does not look like it is supposed to be brazed completely shut.
If you bridge the whole gap with solder or what ever, it might work fine, but it would not be how the machine was designed originaly...

You could try to heat the group connecting piece with a heat gun and then try to cool down the bold/nut with some ice and immediatly try to open it again

But in the end, it is your machine, not mine.

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dmccallum
Posts: 136
Joined: 11 years ago

#7: Post by dmccallum »

Hi Richard,
When you refer to silver solder, I think of silver brazing which is quite a different process to plumbers 'tin' solder. Theres a significant difference between their required temperatures.

I suppose having seen the additional photos and your comments, I'd try the loctite and then the top-nut disassembly (try and remove that existing solder 'bridge' first with a dremel tool of some type. It looks like it might be soft plumbers solder going by the colour difference relative to the joint braze but you have to check. If it is braze then it will be hard and may hamper any disassembly). Clean with citric acid first if possible.

RKRobinson (original poster)
Posts: 33
Joined: 2 years ago

#8: Post by RKRobinson (original poster) »

Thanks. I think Ill go back to working on removing the nut. With the mess that I had to clean to get to this point it seems the previous owner went into panic mode to try to stop the leak. There was a lot of mysterious hardened adhesives in the boiler. With my Gaggia its worked well (so far) to spend the time cleaning things out and just use the proper gasket. With two working machines I have the time.

RKRobinson (original poster)
Posts: 33
Joined: 2 years ago

#9: Post by RKRobinson (original poster) »

Okay I found I was able to undo the nut on the other dipper spout. It was tight but nothing like the problem one. It revealed the problem and what Im up against. I have a few more options on how to undo the nut. Basically it is a gasket problem thats never been replaced but just patched. Rather than replace the gasket it seems they instead always tightened the nut and/or threw in some gook to seal it. Its a relief to finally see what Im dealing with. Let me know if you have any insights. Basically there's three gaskets. Two that seal the dipper tube on the boiler side and one that seals it under the nut. They all were bad in the good dipper and probably dont exist on the bad dipper. Now I just need to get that nut off without further damaging it.

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dmccallum
Posts: 136
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#10: Post by dmccallum »

Well that's a good start. It looks like you'll have to source appropriate viton-rubber/silicon/PTFE o-rings to replace the existing ones. Got some close up shots?