beero Senior Member Joined: 16 Feb 2011 Posts: 11 Location: london Expertise: Just starting
Posted Mon Feb 28, 2011, 5:30am Subject: Zaffiro - problems and help needed
Hi all
I bought a lightly used Isomac Zaffiro and intially im having some problems with it that i would like some advise on.
Brew temp seems to be too hot. If i leave the machine to warm up and flush water through it seems to be coming out way over temp with water spitting from the shower screen and flashing to steam. It takes allot of flushing to get it back down to what i consider normal temp (going by eye) say about 30-40 seconds plus. Is that normal ? I need to do a quick check with a thermometer to confirm what i think but if i brew a shot at the top of the boiler cycle i get espresso spitting out the portafilter half way through the shot !
2 Boiler pressure seems off. The pressure gauge stays at about 4bar even when the machine is off sitting idle and i open the steam valve then when i have fully warmed the machine and pull a shot it goes right up to 13bar. The OVP kicks in at 14.5.
Are both these issues related and should i adjust a few things myself to correct these ? Im reluctant to fiddle with two parameters on a machine i dont know allot. need advise so please help if you can.
bluehaze Senior Member Joined: 9 Feb 2011 Posts: 119 Location: Florida Expertise: Just starting
Espresso: Isomac Rituale Grinder: Baratza Vario
Posted Mon Feb 28, 2011, 8:41am Subject: Re: Zaffiro - problems and help needed
Not sure if you are confusing brew pressure with boiler pressure? Boiler pressure should be around 1.1-1.2 bar. I had the same problem with my rituale, the previous owner had the pstat set to 1.5 and the machine would flash boil for 10-15 seconds LOL I dialed it down to where it bounces between 1.1 and 1.2 and only get a couple seconds of flash boiling. Sounds like you have a similiar issue.
beero Senior Member Joined: 16 Feb 2011 Posts: 11 Location: london Expertise: Just starting
Posted Mon Feb 28, 2011, 9:27am Subject: Re: Zaffiro - problems and help needed
looking into it i think the Zaffiro only has a thermostat not pressure stat so ill have a go at turning this down. sounds like the thermostat on these machine is unreliable - are the symptoms above what youd expect if the thermostat was set too high ?
bluehaze Senior Member Joined: 9 Feb 2011 Posts: 119 Location: Florida Expertise: Just starting
Espresso: Isomac Rituale Grinder: Baratza Vario
Posted Mon Feb 28, 2011, 10:11am Subject: Re: Zaffiro - problems and help needed
Well the higher the temp the higher the pressure. I am still pretty new to all of this myself though so hopefully someone more experienced with your machine can jump in here and help you out.
JGG Senior Member Joined: 31 Mar 2006 Posts: 1,343 Location: Kentucky, US Expertise: I like coffee
Espresso: PID Silvia; PID Alexia Grinder: Mazzer Mini E (A), SJ; Rocky... Roaster: Hottop D w/PID; Thermometric...
Posted Mon Feb 28, 2011, 11:08am Subject: Re: Zaffiro - problems and help needed
I'm almost sure the thermostat on the Zaffiro/Amica is adjustable, and it sounds like it yours may be set too high. Make note of the current dial position, then turn it down a little.
If your pressure gauge is reading 4-ish while idling (also see below), then that is consistent with the thermostat set too high. In fact, that would also be consistent with a shorted (i.e. failed closed) brew thermostat. I think the steam thermostat on these machines is set for a temperature corresponding with between 3 and 4 bar gauge pressure.
A quick word about interpreting the readings on the pressure gauge. This machine doesn't have a vacuum breaker, so there will be so-called "false pressure" in the boiler as it heats up. Once it is up to stable operating temperatures, you can relieve the false pressure by cracking the steam valve for a few seconds, then closing it again. At this point, your pressure gauge reading can be matched up with standard steam tables to give you an estimate of the boiler temperature. If you look up 4 bars gauge pressure (approx. 5 bars absolute pressure), you'll see that this corresponds to a little more than 150C (300F). A properly adjusted thermostat should be closer to 105C (221F), which would read just slightly over 0 bars on the gauge.
The high reading (14.5 bar) during brewing is not related to temperature, but does suggest that the OPV should be adjusted (loosened) for a lower pressure.
beero Senior Member Joined: 16 Feb 2011 Posts: 11 Location: london Expertise: Just starting
Posted Mon Feb 28, 2011, 2:44pm Subject: Re: Zaffiro - problems and help needed
thanks for the reply JGG!
The thermostat is definitely adjustable so i will try that first.
As for the pressure gauge though this reads at 4.5bar when the machine is left off and not warmed up , even if i open the valves the pressure valve doesnt move - is that normal.
JGG Senior Member Joined: 31 Mar 2006 Posts: 1,343 Location: Kentucky, US Expertise: I like coffee
Espresso: PID Silvia; PID Alexia Grinder: Mazzer Mini E (A), SJ; Rocky... Roaster: Hottop D w/PID; Thermometric...
Posted Mon Feb 28, 2011, 3:49pm Subject: Re: Zaffiro - problems and help needed
beero Said:
As for the pressure gauge though this reads at 4.5bar when the machine is left off and not warmed up , even if i open the valves the pressure valve doesnt move - is that normal.
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