sjames Senior Member Joined: 19 Dec 2001 Posts: 464 Location: Melbourne, Australia Expertise: Pro Barista
Espresso: Expobar eb-61 Office Leva Grinder: Mazzer Mini Vac Pot: Unibuy Syphon Drip: Are you talking to me????? Roaster: Genovese Coffee
Posted Tue Apr 12, 2005, 6:04am Subject: Does your Expobar run hot? The (possible) fault and the fix..... finally!
I have just discovered that my 4 month old Office Leva had a faulty return valve in the boiler. This was allowing hot water to flow back along the teflon inlet line and into the heat exchange. (Ouch!!!! That explains the line popping off the OPV nipple.)
A symptom indicating a faulty return valve is delayed water delivery through the group when the pump is activated (lifting the lever). It would sometimes take >5 seconds before water would flow from the screen. The longer the machine was left idle, the longer the pause.
I no longer have splutteirng and fizzing from the group. I'm readjusting my pstat, and when I have done some temperature checks, I'll post the results.
KopiO Senior Member Joined: 18 May 2004 Posts: 22 Location: Singapore Expertise: I love coffee
Espresso: La Marzocco GS3, Expobar... Grinder: Mazzer Mini E Roaster: Gene Cafe, IMEX CR100 (Caffe...
Posted Tue Apr 12, 2005, 8:03pm Subject: Re: Does your Expobar run hot? The fault and the fix..... finally!
sjames Said:
I have just discovered that my 4 month old Office Leva had a faulty return valve in the boiler. This was allowing hot water to flow back along the teflon inlet line and into the heat exchange. (Ouch!!!! That explains the line popping off the OPV nipple.)
A symptom indicating a faulty return valve is delayed water delivery through the group when the pump is activated (lifting the lever). It would sometimes take >5 seconds before water would flow from the screen. The longer the machine was left idle, the longer the pause.
I no longer have splutteirng and fizzing from the group. I'm readjusting my pstat, and when I have done some temperature checks, I'll post the results.
I am not sure if I have the same problem, but I have to do long cooling shots too. I get lots of spluttering and fizzing/steam after it has been left idle for some time. How can I verify the problem?
I have opened up the machine previously to adjust the brew pressure (was 12 bar down to 9+bar) but I have no idea which one is the return valve. DId you change the valve yourself?
Worldman Senior Member Joined: 16 Nov 2004 Posts: 1,791 Location: Pittsburgh, PA, USA Expertise: Professional
Espresso: Expobar Office Control Grinder: Cimbali 6/S
Posted Wed Apr 13, 2005, 1:20am Subject: Re: Does your Expobar run hot? The fault and the fix..... finally!
My Office Contol runs hot but I have no sputtering and not too much water comes from the OPV (unless I grind too fine and/or tamp to hard). I adjusted my P-stat from ~15.5 PSI down to ~14 PSI. Still, I must pull a 6oz. cooling flush before pulling a shot.
KopiO Senior Member Joined: 18 May 2004 Posts: 22 Location: Singapore Expertise: I love coffee
Espresso: La Marzocco GS3, Expobar... Grinder: Mazzer Mini E Roaster: Gene Cafe, IMEX CR100 (Caffe...
Posted Wed Apr 13, 2005, 7:18pm Subject: Re: Does your Expobar run hot? The fault and the fix..... finally!
sjames Said:
A symptom indicating a faulty return valve is delayed water delivery through the group when the pump is activated (lifting the lever). It would sometimes take >5 seconds before water would flow from the screen. The longer the machine was left idle, the longer the pause.
After double checking my machine I don't think I have the same problem. I have all the fizzing and spluttering but the water starts to flow within a second. I presume what I am experiencing is normal which is why the group is flushed after being idle.
sjames Senior Member Joined: 19 Dec 2001 Posts: 464 Location: Melbourne, Australia Expertise: Pro Barista
Espresso: Expobar eb-61 Office Leva Grinder: Mazzer Mini Vac Pot: Unibuy Syphon Drip: Are you talking to me????? Roaster: Genovese Coffee
Posted Wed Apr 13, 2005, 8:06pm Subject: Re: Does your Expobar run hot? The fault and the fix..... finally!
The return valve AFAIK is in the line at the boiler. It stops hot water from flowing back along the inlet line. (Probably called an anti return valve.)
I suspect this valve is common to all machines (not just my Office Leva) due to what it does. Especially machines with teflon/nylon inlet lines like mine.
I did not replace the valve myself. If it is faulty, it is a warranty issue.
Since replacing the valve, I have adjusted the pstat to cycle between 1.2 & 1.4 bar (edit: it's actually between 1.1 & 1.3 bar....sorry folks). After >30 mins warm up, the brew temp is 94-95C (measured during a blank shot with a k type thermocouple, inserted through the PF spout so it is close to the bottom of the filter basket, inside the PF.) This brew temperature is achieved without any flushing! If the machine sits idle for extended periods, it may require one extensive flush. That flush appears to be good for another 30+ minutes.
I am now concerned that my machine is running too cold, as I don't require any sort of cooling flush. I have run out of coffee at it's peak, so I'm having difficulty discerning the flavours, compared with the results I was obtaining when I had to surf the machine previously. However, the mouth feel seems to have improved (much richer).
Before having the machine repaired, the distributor told me that a possible cause for overly hot shots was an incorrect "Disc" in the group head. Apparently, there are different sized discs which help to control the final brew temperature. With my limited understanding of the e-61 group internals, I have no idea where the disc is located or how it works. When I've established whether or not my machine is operating completely correctly, I will contact the distributor to have them rectify the issue and/or explain in detail how thie "Disc" works.
KopiO, if water is not running from your shower screen immediately after activating the pump, I would suspect that you have the same problem. The spluttering and fizzing are not the only indicators of this particular fault.
sjames Senior Member Joined: 19 Dec 2001 Posts: 464 Location: Melbourne, Australia Expertise: Pro Barista
Espresso: Expobar eb-61 Office Leva Grinder: Mazzer Mini Vac Pot: Unibuy Syphon Drip: Are you talking to me????? Roaster: Genovese Coffee
Posted Wed Apr 13, 2005, 8:12pm Subject: Re: Does your Expobar run hot? The fault and the fix..... finally!
KopiO Said:
After double checking my machine I don't think I have the same problem. I have all the fizzing and spluttering but the water starts to flow within a second. I presume what I am experiencing is normal which is why the group is flushed after being idle.
KopiO, My distributor said that cooling flushes of more than 60mls are excessive (unless, perhaps, the machine has been idle too long). If your pstat is set appropriately, and it is still running hot, it may be another issue.
KopiO Senior Member Joined: 18 May 2004 Posts: 22 Location: Singapore Expertise: I love coffee
Espresso: La Marzocco GS3, Expobar... Grinder: Mazzer Mini E Roaster: Gene Cafe, IMEX CR100 (Caffe...
Posted Thu Apr 14, 2005, 2:12am Subject: Re: Does your Expobar run hot? The fault and the fix..... finally!
sjames Said:
KopiO, My distributor said that cooling flushes of more than 60mls are excessive (unless, perhaps, the machine has been idle too long). If your pstat is set appropriately, and it is still running hot, it may be another issue.
My cooling flushes normally take more than 60mls before settling down to a smooth flow (idle for 30 mins), but water does flow almost immediately (after an initial puff of steam!). I will have to check the temperature once I get the appropriate equipment!
Posted Thu Apr 14, 2005, 11:15am Subject: Re: Does your Expobar run hot? The (possible) fault and the fix..... finally!
The p-stat on my Pulser is set to 1.1Bar and it takes a 8oz cooling flush to get the brew temp down to 201F w/ a 25sec recovery time. The water in the reservoir seems to affect the temperature as well. If the water has been sitting in there a while it gets quite warm and results in higher brew temps. By refilling the reservoir with cool water from the tap, the resulting brew temps are several degrees cooler. I am definitely interested in what your distributer performed on your machine. Not having to go through this much trouble to get the temp down would definitely be nice. However, I don't belive my machine is defective, as I have tried two seperate Pulsers and they both perform identically. I also do not have the issue with the water delay from the group.
ev Senior Member Joined: 18 Sep 2004 Posts: 244 Location: Melbourne, Australia Expertise: I love coffee
Espresso: Vibiemme Domobar Super 2004 Grinder: Mazzer Mini
Posted Fri Apr 15, 2005, 3:59am Subject: Re: Does your Expobar run hot? The (possible) fault and the fix..... finally!
G-day Simon. Are you sure that the service agent didn't mod your machine? The fact that you have the PStat set to peak at a whopping 1.4 Bar and you still get perfect temp from start-up sounds strange (good strange!!). Have you tried doing a decent flush (300ml) and then checking the temp? If the temp drops too low, I'd start to question things. I believe there is a little trick used to reduce temp in HX mchines. A restricter disc (copper washer) is jammed in the HX. As you'd be well aware, most HX machines are set at around 1.1 bar and do seem to need a cooling flush. Mine starts at 100C and drops to 94C after a 300ml flush (PStat set to 1.1 Bar). If you find that the temp is pretty stable after a flush, consider yourself extremely lucky.
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