I recently bought a used (less than a year) Appia 1 group after having run an Expobar Pulsar in my small café in South America for 10 years. The Appia seems like a nice step up and also seems like it'll be easier to work on. However, after repairing a leak in the water inlet, spending a week tracking down a replacement for a missing head gasket and, backflushing and descaling the boiler so that the water coming out of the group head finally tasted decent, I got ready for a test extraction and...complete failure. The espresso was weak, sour and blah. Seems like the temperature is too low, but since I didn't have gauges on my Expobar I'm not that familiar with the gauge on this machine.
It's a dual gauge. The upper needle is hanging around at 1 bar or a bit more. However, the lower needle is at just below 5 bar and only moves to around 6 bar when I backflush. I'm not sure if it should show 9 bar at idle, or while extracting, or what? Something is obviously wrong. I might have thought it was a bad gauge if the coffee tasted right, but instead I tried to adjust the pump pressure, first up (clockwise) -- nothing changed on the gauge. Then way up, like 3 revolutions -- and nothings seems to change. There's not a lot of information in the user's manual so I thought maybe someone here would be kind enough to give me some ideas.
The top gauge is the temp of the steam boiler, it should be about 1.1 to 1.3 bar.
The bottom gauge is the brew pressure, it should read your line in water pressure if you are plumbed in. If disconnected from the water supply or if operating on an internal water tank (I do not think that is an option on the Appia) it should read 0. When brewing, it should be about 9 bar. Yes, you should see 9 bar when back flushing.
The gauge can be reading off though and may not be a true picture of what is happening. You should test the brew pressure by taking the spouts off of the Porta Filter and screwing a gauge to the PF. Leave the grounds basket in the PF but do not put coffee in it.
If reading bar, it should be around 9, if reading PSI, then about 130 and in KPA 900
In real life, my name is Wayne P. Anything I post is personal opinion and is only worth as much as anyone else's personal opinion. YMMV!
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Thanks Wayne, I just tried reading the pressure with a gauge on the portafilter, but for some reason on these new simponelli portafilters I'm getting a lot of leakage between the filter cup and the handle which must be bringing down the pressure -- and which never happened on the Expobar portafilters. The reading was 4 bar for what it's worth. Also, last night a friend, who runs a larger 220 machine here in town, came over and looked at it and he commented right way that he's had lots of problems with low municipal water pressure with his machine as well which doesn't get over 7 bar. We did tests last night in my shop and found that when the kitchen had two water taps open, the pressure dropped to 4 or 4.5 bar, but when no water was being used it crept up to just over 5, into the green area. So basically the water pressure might be low, and fluctuates quite a bit. I also temporarily removed my secondary water filter to see if that helped pressure and it seemed to raise it bit, but not much. I'm going to try to get an accurate reading from the group head just to dis cart the possibility of a bad pressure gauge, but it's getting me thinking about a booster pump with a pressure regulator....
Incidentally, I just came across this post from Brady at: Click Here (www.baristaexchange.com) which states that: "On hx machines like your Appia the resting pressure reading is determined by incoming line pressure to the machine. The internal pump only serves to temporarily boost this pressure - usually from 2-5 bars to 9 bars. Once the shot is finished the exhaust on the 3-way valve returns system pressure to match incoming line. Adjusting the pump only effects this "boost" pressure on the machine. For example... Lets say your incoming pressure is 4 bars. You adjust the pump so that while you are pulling a shot it goes to 9 bars."
If this is true, and my machine at rest is showing 4+bar. Then it seems that my pump is barely able to add anything to that? Does anybody have any information on this? Is Brady correct? And if so what does that mean for my pump? Thanks in advance for any assistance.
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