Bianca making hissing noise when idle

Ernie1

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

MediumRoastSteam

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.

Ernie1

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.

dutchy101

I’ve noticed my Minima doing the same

DavecUK

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

Ernie1

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.

DavecUK

Ernie1 Just need to find out which one now.

Ernie1

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?

MediumRoastSteam

Ernie1 What are the two fittings there?

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

CoyoteOldMan

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.

Ernie1

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?

DavecUK

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.

Jollybean

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

Waitforme

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

MediumRoastSteam

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.

Ernie1

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.

MediumRoastSteam

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.

Ernie1

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.

DavecUK

Ernie1 Just contact them…..they might even simply send you the part. At least you’ve covered yourself then.

MediumRoastSteam

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.

coffeealex

Ernie1 If you contact them 9 times out of 10 they will send you the part. They deal with some warranty work that way, or at least they did in the past with me.