Good Day All,

The last few times I've turned on the steam boiler on my Duetto, steam has been escaping from the hot water return hose (name?) that feeds back in to the tank reservoir. The vacuum breaker valve is closing correctly but this line is venting steam and becoming very hot.

I've never been sure the purpose this line is supposed to serve. Is it simply an emergency overfill line in case the auto-fill sensor doesn't stop the boiler from being filled or if the solenoid fails open? There must be a valve in the U-shaped section of the copper pipe shown in my (sorry for the image quality) photo that prevents steam from continuously venting. Is it simply a matter of taking this "valve" apart and cleaning it up?

Thank you for your input!

If steam is coming out of there then you vacuum breaker valve is NOT closing correctly.

That valve is an "OPV, for safety purposes, should the balanced bypass pressure regulation on rotary pump fail."
See pg 5 http://www.bellabarista.co.uk/pdf/IzzoA...lookv5.pdf

Could be stuck or have some crud in it.

It is NOT the OPV it is the vacuum breaker. There is not a tube connected on top of the OPV valve from the top.

I'm going by this image :



From the arrow in the OP, the view is over the steam boiler toward the brew boiler.
The steam boiler vacuum breaker would be outside the lower right of the OP image.

that pic is for the old duetto.... one at the top is the new style...

This new vacuum breaker is mentioned among the Izzo Duetto new features ("New Vacuum Breaker Valve that diverts steam back to water tank" on this page). This change routes the initial sputtering during the boiler warmup back to the reservoir, reducing the risk of an electrical problem due to errant drops of water. Evidently the OP's valve is not closing properly.

OK, but approximate location is for the OPV, pointing down rather than up as in the OP.

EDIT : By downloading and lightening the OP, I can see the pipe from the steam boiler gauge T to the vac break.
Mea culpa

chris wrote:If steam is coming out of there then you vacuum breaker valve is NOT closing correctly.

Thanks Chris. I bought the machine from you. I was first going to call your shop for assistance but I thought I would crowd source. Little did I know you'd be the first to answer!

Thank you everyone else. I will disassemble the vacuum breaker and give it a cleaning. I will report back.

HB wrote:This new vacuum breaker is mentioned among the Izzo Duetto new features ("New Vacuum Breaker Valve that diverts steam back to water tank" on this page). This change routes the initial sputtering during the boiler warmup back to the reservoir, reducing the risk of an electrical problem due to errant drops of water. Evidently the OP's valve is not closing properly.

I didn't connect the dots there. Thank you for clarifying the function of each piece.