Nuova Simonelli Oscar pump cycling for no reason

September 9th, 2013, 11:49 am

I have had my Oscar for about 13 months and am experiencing a problem where the pressure pump comes on intermittently (every hour to hour and a half). It is driving my wife crazy and hence me too! I perform regular maintenance and use water that is at least less than 51ppm per the manual. Lately that figure has been around 10ppm since I installed an RO filter. I cant really find a leak in the machine. Anybody have any ideas?

#2: Post by **kize** » September 9th, 2013, 5:35 pm

Pull the cover off. Something has a slow leak somewhere. Use a small mirror and check all fittings,valves ( breaker and safety) . Steam will show on the mirror were otherwise cannot be seen. If no luck, time to dig deeper.

#3: Post by **jeebsy** » September 10th, 2013, 6:23 am

I've got this since installing the opv. Pump fires every 15 mins or so for a couple of seconds. Will have a look for a leak tonight.

September 10th, 2013, 11:17 am

Kize: That was a good idea. Thank you. I tore the machine apart and sort of loosened and re-tightened whatever I could get at. Seems to have worked as it hasn't done this again. We shall see in a day or two. Thanks again.

#5: Post by **jeebsy** » September 10th, 2013, 6:07 pm

I'm getting some condensation on a bit of mirror at the fitting holding the pipe going from the boiler to the anti vacuum valve. Awkward to tighten as is so going to take it apart tomorrow. Will it be OK to use PTFE on that to get a better seal given it gets really hot?

#6: Post by **kize** » September 10th, 2013, 6:46 pm

Are you saying the vacuum valve is not on the boiler ? But remote via a piece of pipe ? Generally the Teflon thread tape is ok to use on high temp stuff - on the threads. But used in the wrong places and it will end up everywhere in your machine. Just don't over do it.

#7: Post by **jeebsy** » September 10th, 2013, 7:17 pm

At the back of the boiler there's a copper tube coming out to the left which curves round and then has the anti vac attached. Isn't directly attached. Is this an issue? Guy I bought my machine from installed it and he's a coffee machine engineer.

#8: Post by **kize** » September 10th, 2013, 7:48 pm

Not an issue- as long as it doesn't leak or vent onto electronics

#9: Post by **jeebsy** » September 11th, 2013, 1:43 am

Boiler is up to temp now and not getting any condensation from that seal any more, and touch wood the pump hasn't fired so far...

#10: Post by HB » September 11th, 2013, 8:53 am

Sounds like you're in business. For future reference, in addition to using a mirror to find leaks, try using a paper paper tube as a stethoscope. No matter how small the leak, you'll be able to hear it. As a final reminder, don't mess with fittings on a hot espresso machine. Unplug it, wait for the steam boiler to depressurize, and let the machine cool. You don't want to risk tightening a fitting on a pressurized boiler and have it snap off!