# Rancilio Silvia boiler element repair (Tripping RCD/GFI)



## cyberdemon

Hi Guys,

I'm new here, but I thought you might like to see the repair job I've just completed on my Silvia.

A few weeks ago, my Silvia started tripping the RCD (Apparently the Americans call it a GFI). It would trip as soon as I turned it on and knock out the whole house!









I suspected the heating element, but never did I imagine how difficult it would be to change that in a Silvia. It turns out the element is welded to the boiler, so normally in order to replace the element you have to buy a new boiler, which costs about £100.

I noticed someone on eBay (Peter) who used to offer a boiler repair service for the Silvia. He would drill out the old element and fit an element for a different machine (La Pavoni Domus) which is a bolt-in type. I contacted him but sadly he no longer does it. Instead he advised me to either get a new boiler from somewhere like Ferrari Espresso, or try the procedure myself.

I disassembled the machine, and as predicted, the element was shot. It was registering a healthy 53 ohms between terminals, but a dead short (zero ohms) to ground on one of the terminals. Hence the RCD issue.

The element itself was looking much like the multicolour effect here indicating that it had been overheated (but with water still inside the boiler). There was quite a lot of water that came out when I disassembled it, so it looks as though it wasn't my fault. The machine is way out of warranty though sadly.









Peter (the guy from ebay) said that there was a small chance of saving the element if the resistance wire was intact, which it was.

Since the element consists of a copper tube filled with magnesium oxide (MgO) as an electrical insulator, and the resistance wire in the centre, it was possible that the fault was due to a very small amount of moisture seeping into the element through a crack in one of the ceramic seals. MgO is hydroscopic, and only has dielectric strength (i.e. insulation resistance) when it is completely free of moisture.

It is possible to remove the moisture by placing the boiler in an oven at 175C for three hours, allowing it to cool, and then breaking off the ceramic seals and re-sealing the element with anti-creepage paint, epoxy, or some other insulating sealant. I used white enamel paint.

I tested the insulation resistance by connecting mains live to one side of the element and earth to the brass chassis and measuring the current on a multimeter. Stand back and wait for the bang.. It read as zero! Success!

However, filling the boiler with compressed air (to check my plumbing) resulted in this after a few minutes:









Clearly the element was infact cracked somewhere. I filled it with water and pop goes the RCD again.









However, if you have an RCD issue with your silvia where it had *gradually* started to trip the RCD, over the course of weeks/months, as opposed to suddenly as in my case, then *I would very much advise you to try baking your boiler in an oven before you buy a new boiler or element*.

Since the element was indeed knackered, I hacked it off with a hacksaw and drilled it out:









Since MgO is abrasive, you need to use either an old drill bit that you don't mind blunting, or an expensive tungsten carbide bit.

More in my next post.

- Tom


----------



## The Systemic Kid

This sort of post gladdens the heart - fascinating account. Take my hat off to you. Look forward to reading the next chapter.


----------



## cyberdemon

(continued)

So I ordered a Pavoni element from Ferrari Espresso along with a new gasket and some other bits and pieces, and I immediately got a phone call from Frank, the owner of Ferrari Espresso, asking if I really meant to order a Pavoni element with a Rancilio gasket!

I explained what I was attempting to do, and he was very interested indeed. He said that the Pavoni element would fit but it is a bit too squat for the Silvia and would be quite high off of the bottom of the boiler, and so would be vulnerable to overheating during steaming.

He suggested that a better fit might be the element for the Isomac Venus, which will go all the way to the bottom, and he even said I could send it back if it doesn't fit. (normally, elements would be non-returnable)

So I got the Venus element, but the screws on that one are a whopping 13mm, compared to the 8mm holes for the La Pavoni element. This starts to create issues with the lumps and bumps on the inside of the Silvia boiler (e.g. the ridge where the thermostats are fixed on)









(Yes, my Silvia's steel frame is a bit rusted. Better do something about that too!)









Judging by the washers, this element is only JUST going to fit. In fact if you look at my previous picture of the drilled-out boiler, simply enlarging the holes to 13mm on the same centres would leave them perilously close to the bumps on the inside of the boiler, and would risk not getting a seal.

Besides, I don't even have a 13mm drill, so I had to bodge it by expanding the holes with a milling machine. This meant I could shift the centres of the holes away from the bumps and edges like so:









The element itself is quite flexible, so it doesn't mind being bent slightly to fit holes slightly closer together than normal.

Removing the burrs from the inside wasn't easy either. I had to use a dremel-like tool with an abrasive point, as well as a wire brush and a bunch of other rotary toolbits to try and clean out the burrs and limescale around the holes as best as I could.

More in a bit (I can only post 5 photos at a time apparently)

P.S. At this point I've probably used up more time than it was worth in saving the 60 odd quid for buying a new boiler, and I've probably used more tools than the average coffee enthusiast has in his garage. So if you are doing this yourself,* I cannot recommend the Isomac Venus element*. Either use the La Pavoni element (which has 8mm screws, so much easier to fit) and accept that it will sit a little high out of the water so you must be extra-careful about making sure your boiler is full, or just take the £100 hit and buy a new boiler. Or even better, fix your old element if you can using Peter's the bake-in-the-oven trick in my first post.

The Pavoni element is also slightly lower wattage than the original Silvia element (900W vs 1100W) so maybe less likely to fail, but it also means it will take longer to go from brewing temperature to steaming temperature.

The Isomac Venus element on the other hand is 1200W. Overpowered, but I plan to use it with a phase-angle controlled (i.e. dimming) PID controller.


----------



## cyberdemon

Ok so I have milled out my holes and enlarged them to 13mm. They are actually more-or-less circular, which I think is impressive given that it is a manual milling machine!

The element fits beautifully, and I tighten up the nuts.









I then assemble the machine, and run the pump to take it up to brew pressure.









You can just about see a tiny bit of water seeping from under the half-nuts. Rats. Not one but two leaks!!

Much cursing and more dremel-polishing later, I flip the PTFE washers over and try again. (the teflon washers have to be deformed in order to seal)

Run the pump and.. It works! No leaks.









That is until I hit the steam switch:









At this point I am cursing like a pub full of Motherwell F.C. fans.

However, when dealing with teflon washers, the answer is usually "more compression". So a healthy dose of rage is actually useful here.

I tightened up the nuts as tight as they would go, and tightened them some more. No more leaks!

It works! I make myself a nice coffee (not the best, as I don't have my grinder with me at this point), but after living off instant for weeks it's like Mana from Heaven.









I should probably tidy up my garage at this point.. Bah sod it.


----------



## glevum

An excellent read.....and what a commitment to getting it finished. The money saved can go to a grinder fund. Well done


----------



## The Systemic Kid

You deserve an award!


----------



## cyberdemon

Glevum: Thanks!

The money saved isn't so much going to a grinder fund. (I have a grinder, but it was in my student house in Reading. I had brought the Silvia back home to Southampton (on the bus/train!) in order to fix it, but couldn't carry the grinder too) Instead the money is going towards repainting the chassis, adding a pressure gauge, and a few other nice-to-haves.









So, I said I was going to do something about that rusty old frame.

I got a quote to shot blast, zinc prime and polyester powdercoat the frame from A1 Powder Coatings near where I live in Southampton. £30. Not bad!

That means I'm going to be without my coffee machine for another week though, and it's doubly bad because I have brought my grinder back from my student house in Reading now.

What shall I do?









Measure the holes on the back of the boiler (M6, 40mm spacing, 15mm from edge, iirc.) and drill them into a bit of wood, of course.

Clamp the wood in a vice, and I have a working coffee machine!

A bit of old innertube zip-tied around the solenoid relief outlet keeps it from dripping down my workbench.

You can also see I've added the pressure gauge I got for 15 quid off eBay. Not sure where to mount it for the finished product though!

Mind you, I quite like the machine in this state. It's quite steampunk! (literally I guess, since there's actually a boiler and steam involved)

Some really good coffee too!









The chassis finally arrives back from the powder-coaters.

I was going to get it done in the same black as the original. But seeing as I'm going to be adding a pressure gauge and PID, I might as well go for the modified look. So I asked for bright (RAL 3020) Ferrari Red:









Millie likes it! (as a scratching-post)









So does Pingu. (Millie doesn't like Pingu)

My last few pictures will be of the assembled machine!


----------



## Glenn

Thankyou for sharing the steps so far.

Looks like the steam wand could do with a good clean


----------



## coffeechap

fabulous i love it when people use a bit of inginuity to solve a problem, well done and enjoy the silvia.


----------



## cyberdemon

So yes, last few pictures and I'm done.

Putting the machine back together:









And now settling in and making some coffee.









The red is much subtler with the stainless steel panels on, but I think it's still quite striking.

Now I just need to work out where I'm going to put my PID controller and pressure gauge!

I just can't bring myself to start drilling holes in my nice pristine Silvia!


----------



## glevum

Cant wait to see the finished version now. Ive never seen a resprayed Silvia frame.


----------



## cyberdemon

glevum said:


> Cant wait to see the finished version now. Ive never seen a resprayed Silvia frame.


Well now you have!









You'll notice I left off the group head cover. My original is flaking and looks horrible, so i'm thinking of leaving it like that.

I might even take a rotary wire brush, sandpaper and a bit of brasso and give it a good polishing up, what do you think?

By the way, when I was pressure testing it with the air compressor, I noticed that the OPV lets through a very small amount even when it is well under pressure. Is that normal?

It brews at around 8.5 bar, according to my pressure gauge. That seems high enough..

Any ideas on what to do with the pressure gauge and PID?

I'm thinking of making an external box out of either wood or aluminum, and running a conduit containing a small pipe and a few wires through the main cable entry of the Silvia.

You'll notice in my assembly picture I have a green pipe and a brown wire. The pipe goes to a compression T fitting which is currently blanked off - a placeholder for the pressure gauge, and the brown wire is a loop connecting the original thermostat circuit to the live side of the boiler.

I will eventually cut that, perhaps adding a double-pole switch so that I can disconnect the PID for reprogramming.

The thin green wire is the thermocouple, which is clamped round the middle thermostat screw on the top of the boiler.


----------



## coffeechap

whats up with the steam wand?


----------



## cyberdemon

As Glenn said, it could do with a good clean.

In my last picture set it is wrapped in a wet dishcloth to soak into all the dried crusted milk.

When I take the cloth off after an hour or so, the crud just peels off really easy. There was about a 1mm thick layer of it!!


----------



## glevum

Myespresso sell thoses chrome / plastic group cover for about a tenner. Seem to last a few years before they peel again


----------



## cyberdemon

The Systemic Kid said:


> You deserve an award!


Cheers!









Though I should say that none of this would have been possible without the help of Peter (eBay/laptitude) and Frank from Ferrari Espresso



glevum said:


> Myespresso sell thoses chrome / plastic group cover for about a tenner. Seem to last a few years before they peel again


So I see. Ferrari does them too, but I prefer the brass if I'm honest! Even before it started peeling, the plastic cover seemed a bit, well, plasticky!


----------



## painty

Super project thread, well done. That re powder coating looks good and a reasonable cost.


----------

