Flow issues with V2 Mini!

[brandon]

Hi,

I posted this in Home Barista as well but figured I'd start an account here as you guys are the experts. I bought a V2 Mini a couple years ago but have had it in storage for the last ~15 months (I was in an apartment which had 0 space for it). I just took it out of storage this weekend and am having obvious flow problems. I started with the "reboot" of holding the on/off and hot water buttons at the same time, but no water came out of the grouphead and the machine automatically shut itself off after a minute, leaving only the boiler light blinking. I tried this several times, including trying to pull blank shots. A couple times, *some* (but not much) water came out of the grouphead, but it hasn't happened since. Most of the time lights 14-16 are blinking after I try this, which I believe indicates a flow problem.

I've had flow issues before but they were always easily solved by (re)moving the water softener. So I did that and still no luck. Then I tried cleaning the valve inside the reservoir (which connects the water supply to the machine) by poking through it with the wires on the steel brush grouphead cleaning accessory. Still no luck. I took off the machine casing and noticed two things: The lower tube which I circled in red had water in it and no apparent blockage and the upper tube circled in red appeared to be pumping something slowly into the boiler -- water or air I'm not sure.

I am not a very handy person, so detailed help is much appreciated. Thanks!

IMG_000001331.jpg (390.44 KiB) Viewed 9931 times

[chas]

First let me caveat this response by saying I have owned all three models of the plumbed S1, but never a Mini. So everything I say here is based on what I have learned about the Mini from other users on the Forum and my overall general knowledge of the S1 design.

Did you follow the steps below exactly starting with the machine in Standby mode? I can see where you might get to the point where the device would shut off after one minute if the steam boiler didn't complete filling if you pressed these buttons starting with the V2 Mini in the ON mode, but I would not think it should do this if you pressed them starting in Standby mode. Your symptoms sound like this pump priming and boiler filling process is not working successfully. As noted below in Step 5 if you are correctly in the priming mode, the Empty lamp should be blinking.

4.4 Filling the Water Tank
1) Remove the drip tray (1)
2) Remove the water tank (4) and fill with soft water to ensure against mineral buildup in your boilers
3) Replace the water tank (4) and the drip tray (1)
4) Insert the plug into the 110V AC socket, the On/STBY light (22) starts flashing. (Stand-by mode).
5) Press the ON / OFF (27) and Hot Water (23) buttons simultaneously. During this stage, the control lights EMPTY and On/STBY (22) blink while the pump runs
6) Once you see water coming from the group (10), release both buttons. The unit is now in Standby mode with the On/STBY light

[brandon]

Yes, that's what I've done and all three of those lights are blinking until the auto shut off, at which point only the boiler light flashes.

I'll add that I disconnected the hose attached to the pump on the right side (as viewedfrom the back in the photo...the one wrapped in coil) and water poured out of it, implying there is flow to the pump...

[chas]

This is pretty far out there as a possibility but at least it's easy to check. The vacuum breaker valve is on top of the steam boiler closest to the front of the boiler. It's surrounded by a copper cup and there is a cut-out in the top chassis frame bar so that it can be accessed for removal and replacement, when required.

There is a pin in the middle of the vacuum break valve. When the temperature comes close to boiling, that pin pops up and closes so that the pressure can build to the point where the temperature of the boiler can go above 100C. When the boiler is off and cooled down, that pin is supposed to open back up and let air into the boiler. When the boiler is empty it is probably necessary for this pin to be down in the open position so that water can fill the boiler while letting the air escape.

Maybe that pin is stuck in the up/closed position. You should be able to press down on it to check. If that valve is open you should be able to grab the pin and freely move it up and down.

[brandon]

Pin is down. It's easy to pull up (no resistance) but definitely down. Also would that explain the lack of flow to the grouphead?

[chas]

You may need to pull a line from the output of the pump to see if the pump is working.

[brandon]

What do you mean? How do I "pull a line"?

Isn't the tube I disconnected from the right side of the pump (covered in the coil) from the output?

[chas]

I thought that was the input line from that tank. Perhaps I am wrong.

Unless an actual Mini owner comes through, you may be best served by talking to a Chris Coffee tech tomorrow morning. Even if your warranty has expired they will certainly give you suggestions about what to check for free.

[brandon]

Nope, you are right. I think that is an input. There is some circularity in the connections that I don't seem to understand. (Not necessary for fixing the problem at hand.)

[chas]

Yes, if you look at the flow diagram in the Mini user's manual, there is a feedback path from the output of the pump back to the input. The group pressure regulator is in this loop. With the regulator set for 9 bar, when the pressure exceeds 9 bar a little valve opens and passes water from the output of the pump to the input, this lowers the pressure then the valve closes. So in order to keep the pressure at 9 bar this valve is opening and closely at a rapid rate. This is why the needle on the group pressure gauge vibrates around 9bar when pulling a shot rather than showing a nice steady reading.

[brandon]

Fixed it. Disconnected the hose coming from the reservoir and attached it to a turkey baster to force-prime the pump.

A little tricky putting the damn case back together, though...

[chas]

Ha! Often when doing repairs or adjustments that part has taken less time than getting those damn side panels realigned and reattached.