Questions - my first day with Mini V2

Post general questions about operation of your new Mini here. Due to many similarities with the original VII you should also check the VII forum.
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AndyPanda
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Questions - my first day with Mini V2

Post by AndyPanda » Wed May 31, 2017 8:54 pm

OK ... I purchased a used Mini V2. The seller claimed it was 2 years old and the brew boiler heater had failed. I ordered the brew boiler heater and got it installed and working today. While I was waiting for the part to arrive, I cleaned the machine up --- the group was filthy with old coffee but nice and clean now.

The steam boiler looked very clean without any scaling - but the shower screen for the hot water nozzle was completely crusted with white. I thought it was dried milk from splashes while steaming --- but nothing would clean it off until I soaked the nozzle in white vinegar and then it dissolved and the screen is nice a clean now. So based on that, I'm assuming that was scale crusting the screen. There was no scale to be seen in the steam boiler when looking through the hole for the anti siphon valve - so previous owner probably descaled the boiler but didn't run any descaler through the hot water dispenser.

I hear a fan whirring whenever the steam boiler is heating. I thought the fan was only on the older machines and newer ones had a solid state relay board without the fan. Does that mean my machine is older than the seller claimed? Anyone know what year they stopped using the fan?

The hot water dispenser sputters and spits and shoots water and steam out at high speed - is that normal? I made a youtube video in the hopes that someone here can answer if this is normal or not.
https://youtu.be/8jDCOBy7sbQ

AndyPanda
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Re: Questions - my first day with Mini V2

Post by AndyPanda » Wed May 31, 2017 9:45 pm

I just noticed that my steam pressure gauge is registering really low (though I seem to have lots of steam). It's only registering in the blue (.5 bar) even though the steam temp offset is adjusted to +3. I also notice my brew pressure is registering 2 bars even though I'm not pulling a shot - so I'm not putting a lot of faith in these gauges.
Gauges.jpg
Gauges.jpg (54.54 KiB) Viewed 3640 times
hmmm ... while looking at the gauge, I see the mfg label showing it was built in 2008. So much for the trustworthiness of the previous owner who told me this was a 2 year old machine :) unless it sat in stock at Chris Coffee for 7 years before it was sold. But that explains why it has the fan on the steam boiler triac board.

AndyPanda
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Re: Questions - my first day with Mini V2

Post by AndyPanda » Wed May 31, 2017 11:23 pm

I found that letting the boiler just stay up to temp for a few hours ... eventually the gauge starts reading up around 1-1.2 bars. And then, even after turning the machine off and purging all the steam pressure thru the wand - the gauge stays up at 1-1.2 bars. So I'm guessing there is some scale that made it into the tubing or the gauge is just old. Probably not worth trying to fix since the steam wand seems to be producing plenty of dry steam.

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chas
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Re: Questions - my first day with Mini V2

Post by chas » Thu Jun 01, 2017 9:51 am

AndyPanda wrote:I just noticed that my steam pressure gauge is registering really low (though I seem to have lots of steam). It's only registering in the blue (.5 bar) even though the steam temp offset is adjusted to +3. I also notice my brew pressure is registering 2 bars even though I'm not pulling a shot - so I'm not putting a lot of faith in these gauges.Gauges.jpg

hmmm ... while looking at the gauge, I see the mfg label showing it was built in 2008. So much for the trustworthiness of the previous owner who told me this was a 2 year old machine :) unless it sat in stock at Chris Coffee for 7 years before it was sold. But that explains why it has the fan on the steam boiler triac board.
The way the gauge is plumbed into the Mini the group gauge value is meaningless except when pulling a shot while the machine is on. There are only two times when it is (or should be) accurate:

1) While pulling a shot
2) When the machine is cold it should be exactly on zero

Definitely check the machine over well. If the previous owner was able to lie about a 9 year old machine being 2 years old you never know what other information he stretched or omitted.
Chas
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Lav
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Re: Questions - my first day with Mini V2

Post by Lav » Fri Jun 02, 2017 10:34 am

I agree to Chas' observations and also my hot water tap deliver water as yours - and really should as the pressure has been increased (+3) and the water will come out overheated and flash boil.
I also got quite an amount of wet steam to begin with. Using that to wetten my cloth so that the steam wand can be cleaned after use....
Check the manufacturing date on the inside of the plastic panel to the right (hidden by the drip tray)


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AndyPanda
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Re: Questions - my first day with Mini V2

Post by AndyPanda » Fri Jun 02, 2017 9:09 pm

I've been reading thru the archives and learning a lot. I thought I'd post a list of what I've found and learned so far.

So ... currently I have the steam offset off (neither + nor -) and if I heat up the steam boiler and leave it heated up for an hour or two, the pressure gauge reads normally. It just takes a long time as it very gradually comes up (the gauge I mean - the boiler comes up to heat quickly) - and then when you turn the boiler off the gauge takes an hour or so before it gets back to zero (even if you open the steam valve and let all the pressure out of the boiler). No worries - but I'm just curious if this is by design (does yours behave that way?) or an indication that something is restricted in the line to the gauge? (BTW - I noticed that the brew pressure gauge eventually goes to zero when the machine is off. It reads correctly when pulling a shot, it just doesn't go all the way back to zero).

I noticed a bit of smell/taste to the water from steam boiler (smelled like some scented descaler had been used in the past - flowery/perfumy) - so I did a thorough descaling of the steam boiler with white vinegar (siphon and funnel method) and several rinses and flushes and now I get clean tasting water from the hot water spigot. I still notice a tiny bit of the funny scent from the steam wand but that is fading fast as I run a lot of steam thru.

Then I noticed a different smell/taste in the water from the brew boiler - so I opened that up again. Remember this machine had a bad brew heater when I bought it so I put in a new heater from Chris Coffee. I didn't think to wash the heater before installing it (it arrived in a plastic bag) - but when I took it back out, I could tell that the smell was coming from the new heater. So I scrubbed the heater down with a toothbrush and detergent and got the smell off of it (something from where it was manufactured I guess) - and I scrubbed out the brew boiler while I was at it. Now I get fresh smelling/tasting water from the group.

I've got a 58mm thermofilter - but I don't have a 53mm. I do have a nice instant read thermocouple probe -- so I did the cut down styrofoam testing and got a feel for how much pre-shot flushing is required to get the temp stable. Surprising to me just how much fussing around is required to get a stable shot temp (especially since the touted temp stability was the whole reason I bought this machine). But I'm gradually settling into the routine. In order to do a cross check against my thermocouple in styrofoam cup tests, I used the extreme temp function to set the brew temp to 100c (I'm at sea level - so that should be boiling) and found that it took a +4 offset to see/hear steam sputtering at the grouphead (after 2-3 warming flushes) and +3 offset just stopped the steam at the grouphead. So I think that confirms that +3 is a good spot for the offset (+3 was where I had determined when using the styro cup test) - and I've got the brew temp set back to 93c for now.

Water reservoir valve was leaking when tank was pulled out - so I pulled that apart and cleaned it really well and now it's working. So pretty much everything is working well and now I just need to learn the routine to start pulling great shots.

Staypower
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Re: Questions - my first day with Mini V2

Post by Staypower » Wed Jan 22, 2020 2:32 am

I've recently bought one and fortunately, it is absolutely ok.

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