Just when I thought I’d made a year of trouble free ownership my Bianca has starting making a subtle hissing noise when warmed up. It’s definitely quiet but noticeable.

I haven’t taken the top off yet but wondered if there’s any common issues to watch for when I open it up.

Thanks

take the top off and check things. It’s normal for the machine to make a hissing noise when warming up - that’s the boiler getting to temperature and the vacuum breaker shutting. Maybe you never paid attention to it?

Apart from that, hard to tell exactly as there’s not enough detail to follow.

    MediumRoastSteam

    Thanks, it’s more after the machine has warmed up, I noticed it just today and yesterday.

    I’ll have a quick look under the hood and report back.

    I’ve noticed my Minima doing the same

    Top off time and an examination. One quick check…does it do it with steam boiler off. If no…then off with the top and search around.

    Look in bottom plates for evidence of weeps which heat expansion turns into hisses/stops altogether. Check

    • Fittings
    • Vacuum Breaker
    • Safety Valve

    Ok had a look this morning.

    The hissing appears to be coming from one of these fittings. It stops when the steam is activated and then starts again when the steam tap is off and then remains constant.

      I’ve got my ear as close as is safe with the heat and really struggling to determine.

      Also no evidence of air bubbles or leaks from either.

      What are the two fittings there?

        Ernie1 What are the two fittings there?

        • Top picture: Anti-vac valve (aka Vacuum breaker);
        • bottom picture: Safety valve.

          MediumRoastSteam great, thanks.

          Does the safety valve work somewhat constantly to allow an escape of pressure? Or is it a failsafe only active under problematic circumstances?

            You may find using the tube from a roll of kitchen paper as a stethoscope helps to identify the culprit

            Ernie1 Does the safety valve work somewhat constantly to allow an escape of pressure? Or is it a failsafe only active under problematic circumstances?

            It’s a fail-safe and requires replacement if it constantly leaks under normal pressures.

            Ernie1 Have you tried with a long-ish screwdriver used as a stethoscope? Just put the tip of the screwdriver on a metal surface near the fitting (or on the fitting), and your ear almost against the handle. It transmits vibration/noise, but not heat - I learned this from a mechanic who would use it to locate the source of noises in engines.

            Are they far enough apart to put a wee bit of soapy water on them to see which one creates bubbles ?

            Pull the hoses out of the fittings carefully. You’ll know pretty quickly which one is the culprit.

            Remember the vacuum breaker will “spit” immediately after warm up. So be really to catch the water if you follow that route.

            Ok thanks for the further replies.

            It’s the vacuum breaker. It hisses noticeably louder when the steam boiler is heating up but I’ve just monitored it for half and hour or so and it keeps hissing constantly.

            No evidence of damage on the tube itself and the noise is coming from the fitting.

            Also no signs of actual moisture but I’m guessing given how hot it is any slight moisture would evaporate quickly.

              Ernie1 if you are sure it’s the vacuum breaker, you can try cleaning it or just buy a new one and replace it. It’s an easy job. Check Lelit Insider on YouTube I’m sure there’s a few videos there on the matter.

              Thanks.

              Removed it, gave it a clean and still the same. I see it’s a £9.99 part so I may as well swap it myself.

              It’s still under BB warranty, is this going to void my warranty?

              Seems a bit excessive to send it to them for a £10 repair.

                Ernie1 - back in the day they send me a whole gicar box and tank assembly to replace it myself on a Pro-700.

                Hopefully they will just send you the part.