adamgoldberg Senior Member Joined: 10 Mar 2004 Posts: 51 Location: Virginia Expertise: I love coffee
Espresso: Expobar Control Grinder: Mazzer Mini Drip: Technivorm KBT741
Posted Tue Aug 24, 2004, 6:16am Subject: Expobar Control - 'hissing' sound?
This morning my wife told me that the espresso machine was making a 'hissing' noise, so she had just turned it off. I turned it back on and made sure it worked - steam, hot water and extraction ... but then it started hissing and the pump was running continuously.
Actually it sounded like a steam leak.
I wonder if this is an overpressure valve operating or something? But why would the pump be running too?
gajetjunkie Senior Member Joined: 14 Nov 2003 Posts: 139 Location: Houston , TX Expertise: I love coffee
Espresso: La Valentina Semi-auto ,... Grinder: Mazzer Mini ,Capresso... Vac Pot: Not yet , French Press Drip: Technivorm Roaster: Behmor , SC/TO
Posted Tue Aug 24, 2004, 7:10am Subject: Re: Expobar Control - 'hissing' sound?
The Expobar does not have an overpressure release valve , it does have a vacuum breaker. If the vacuum breaker does not seal up when your machine is up to operating temp , it will leak steam and hiss. It could need replacing or it might have some scale build up on the valve.
Try removing the valve ,soaking it in descale solution and reinstalling it. That might do the trick. The valve is on the top of the boiler. It is made of brass it has a small brass rod sticking up in the middle , If the machine is up to operating temp you will see steam leaking from the little rod , if that is your problem. If not then the leak/hiss is from something else.
If you do remove the valve make sure you bleed all the steam pressure thru the steam wand first .
I'm not sure why the pump would be running continuously. If the wire to the refill sensor were disconnected this would cause the pump to run continuously. Look on top of the boiler , you will see a silver fitting with a silver rod sticking up , it should have a white wire connected to it , if it doesn't then you will need to find the white wire with a connector on the end and attach it to the refill sensor.
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