Breville Dual Boiler...

Contrary to popular belief, there _are_ some repair parts available for these from ereplacementparts.com. I just ordered a new 3-way solenoid for mine, which has become buzzy after 5 years of good service... Still works, just buzzy now, and I don't know how much longer it will last.

But that's not what I'm asking about here. I'm asking about something much more mundane, the little O-rings that seal the hole where the probes enter the boiler. Those are bound to leak one day, but they are SUPER easy to check and replace, so it's probably not worth sending the machine back to Breville for their $350 "fix it or replace the machine" repair service. Yeah, you'd get the latest firmware update if you did it, but mine works fine without a firmware update. Not worth the $350 to me, for easy things I can fix myself.

Anyhow, I can size out the O-rings easily enough. Just asking for a little guidance on choosing the right material. Viton? Buna-N? Other?

-Peter

On machines I've seen (not a lot), it's normally teflon or copper washer. I don't see why (hi-temp) viton wouldn't work though - except that requiring more effort in removal when it's old and baked hard onto the surface.

I don't have any experience of your particular machine, but based on other machines I've worked on, Viton (or equivalent) has been specified for o-rings attached directly to brew boilers and silicone for steam boilers. I think either is rated higher than the temps. that will be encountered, but silicone much more so. There might be a hardness specification as well as size, but I doubt that the machine manufacturer has had anything exotic produced for their particular application and they use standard off the shelf stuff.

I assume we are talking about proper O-ring applications where they are fitted into a machined groove and not subject to any possible tearing. If so, it is unlikely either material would deform over time and become difficult to remove if ever needed.

I'd try it and see if the time comes.

Thanks, guys. That's more than enough good info to get started. If they don't last as long as OEM, at least they are easy to change and I can try different variations of compounds until I get the most durable.

-Peter

Of course Viton will withstand the temperature - but doesn't the choice of a seal also depend on the mechanics of the clamping mechanism?

I always assumed copper (as well as Teflon) were used if the surfaces rotated against each other. Like sealing a fitting.

Orings are used if there is a groove an if the surfaces do not rotate - as in a heater tightened by 3 screws.

If one was to tighten a fitting against a Viton seal it would tear apart.

Peter,
Will you describe the procedure for removal and replacement?

In answer to both John and Assaf:

No turning involved, so no worries about tearing the o-ring. You press the wire with the sensor into a short tube on top of the boiler, with the probe itself going through the o-ring. The probe/wire assembly has a flange that bottoms on the o-ring, compressing it, and preventing further insertion. The sensor-wire assembly is held in compression against the o-ring, and prevented from backing out, by a simple spring clip that engages grooves in the short tube on top of the boiler that aligns the probe.

Remember, the actual factory o-rings are not readily available to the general public, so their composition is unknown. Viton would just be a first, best guess. Unless I'm failing to consider something, at the worst, they might not last as long as the factory o-rings, in which case they are easy enough to replace, and there's always the option to experiment with more exotic compositions, as well.

John, I'm assuming you are at least comfortable taking off the back and top covers, which is super easy. But you will need a Torx bit for the outer bolts (I forget which size, but it's common). Removal of the top cover gives wide open access to the tops of the boilers (steam and brew).

-Peter

Peter,
How do you remove the tubes inserted in top of the boiler?

https://goo.gl/photos/GrZWyBJusWKCvRgb6

If you expand the pic to look closely, you can see the little spring clips (shaped roughly like an open ended peanut). You take your needle nosed pliers or sturdy tweezers and pull the clip back or out completely. Then you just lift out the probe directly. The O-ring lies beneath it. Is that what you were asking?

-Peter

Yes thanks.