I'd really appreciate some advice on the performance of my 9 month old Quickmill Anita HX machine.

Background: The machine has a PID'ed boiler that is set on 250* and that results in about 1.1-1.15 bar pressure. This has been and is constant. I get nice overheated water from the HX and steam with no problem. The NY reservoir water I use has 30-35 ppm solids and much of the early 9 months of use I've Brita filtered it resulting in about 20-25 ppm solids. I've stopped using Brita filtered water the past couple of months. Therefore, I doubt I have problematic scale buildup after 9 months BUT who knows.

The Problem: My grouphead temperature using Eric's probe had always been 213.5 to 214* This was pretty darn constant and my flushes and recoveries had been calibrated on this and all was working well with my drinks. Lately however, the grouphead temperature is down to 210.5 and has even been as low as 209. The boiler temperature is still 250 and the pressure remains 1.1-1.15 bar. I get good overheated water when I initiate a flush and good steaming. My recovery time between drinks is affected and the grouphead temperature measured by the probe seems to get significantly lower after pulling a shot then it did before.

Something seems amiss and it is affecting my espresso. I would not think I need to descale but I really don't know. The ambient temperature in the room is not affected and if anything its warmer now in spring then it was in winter. The only other recent "symptom" I've had was after taking some (250-300 ml) hot water from the tap. The pump continued longer then I expected so I shut the machine down and started it up after a minute of so. It continued pumping and I noticed as much hot water returning to the reservoir as being drained. The boiler therefore was not filling. After shutting down again the pump worked properly and filled the boiler but I do note that the water reservoir does get warm from returning water and I can't say I've seen that much previously.

Can anyone think of what might be lowering my grouphead temperatures and how I can fix it? Could I have a problem with the thermosyphon loop in a QM Anita? Many thanks.

When was the last time you chemically backflushed? My guess would be a coating of coffee oils on the probe...

Tim

Thanks or responding. I religiously backflush with Calfiza every three to (at most) four weeks. I last did it on 4/30. I can check the probe for residue.

In a way your theory might be interesting as I thought it very difficult to believe that the mass of the grouphead could get cooled as easily as it seemed from my temperature readings after flushes. They are not nearly as "off" as in cases I've read here of thermosyphon stall on other brand machines (VBM ?) therefore I don't think that air bubbles or such is my problem.

Geoffrey -

I would check the water level in the boiler immediately after it goes through its "cold fill" - like in the morning. I just measured the boiler and probe dimensions and the numbers work out such that "design" water level is 4.40" in the boiler. This info contradicts some numbers I provided in a previous post but keep in mind that actual water levels will typically be a little higher than the 4.40" depending upon electrical circuit sensitivity. You can measure water level with a 1/16" wooden dowel, lightly sanded to enable the wood to show the water better.

A water level higher than normal, as would be encountered with some corrosion buildup on the level probe, will reduce grouphead temperatures.

edit - drawing dimensions changed slightly

Eric

Thanks for going to the trouble to post that diagram. I'm away from home this weekend with the machine off. I'll get to it when I'm back. I assume I need to remove the water level sensor and use the dowel in its place to do this?

No, the water level sensor can be a toughie because of access. Of course it can be done but . . .

I would undress the machine a little and turn it on from cold. The fill should come on for about 3 to 4 seconds. Now shut her down and unplug and loosen/disconnect the hot water spigot tubing. You don't need to remove the tube that extends into the boiler. Now simply stick a wooden dowel into the hole and let it go to the bottom of the boiler. Remove & measure. Repeat for good luck.

Hi Eric

Still not home by my machine. I assume the hot spigot outlet with hoses is on top of the boiler where I can get a probe down into the boiler.

If there is corrosion on the sensor probe might that have caused my temporary problem with refill (described above) where hot water continued to flow into the reservoir at the same rate as fresh water was being pumped into the boiler?

Thanks

Yes, the hot water outlet is on top of the boiler. A 6" long, 8 mm tube extends into the boiler to draw water from the bottom. This tube does not need to be removed as your homemade dipstick (1/16" dowel) will be inserted into the above tube till it touches bottom. Once you check the water level this way, you will be amazed as to how simple it really is.

When you use the expression "hot water", is that water you could not hold your finger under? If so, that is water getting past a malfunctioning OPV and NO WATER should get past the OPV under simple flushing or boiler filling conditions. Water does flow from the pump priming valve at all times (except brewing) but this water is at reservoir temperature, i.e., not hot. Anita's water reservoir can reach ABOUT 100 F after being on for, say 8 hours.

Eric

My impression was that the water returning to the reservoir was VERY hot and quickly made the temperature of the reservoir well above 100*. After shutting down and turning on the machine again it seemed to reurn to "normal" with short bursts of refilling and shut off.

Could an OPV problem affect boiler fill levels and might that be the source of my grouphead temperature fluctuation?

Could an OPV problem affect boiler fill levels and might that be the source of my grouphead temperature fluctuation?

No, OPV and boiler fill are unrelated, sorta.

HOWEVER, it certainly appears as though you have a leaking or intermittently leaking OPV and that would, in fact, flow water through the hx and out the OPV back to the reservoir even during a boiler fill - see schematic below.

The now cooler hx would remove some heat from the group and lower its temp. So, time to remove the OPV. But before you do, order some replacement parts from CC (new OPV "rubber" insert, new o-ring, food-safe grease).

I'd like to update my problems with the QM Anita as I described above so others might diagnose potential problems with their machine.

It turns out that I had two distinct and different malfunctions.

The problem with the grouphead temperature being lower and drink brew temperatures being too cool especially on second and third attempts after an initial one when the group was hot turned out to be a PID tuning problem. I had never actually stood by my machine and followed its heating progress from a cool start. I have a PID'ed boiler from Dave at Hitechespresso and typically set it at 250* F resulting in about 1.1-1.15 bar and 213* F or so grouphead temperature on EricS's probe. Well, after nine months of use I discovered that on heating from a cool machine it would go all the way up to 265* F and as much as 1.55 bar into the red. I have a time course of this and it slowly went down to proper 250* temperature but fluctuated more then I initially ever recall the PID readings doing before. Dave suggested an automatic retuning of the PID which I did using his instructions. Low and behold the temperatures behave as they should. I don't know how the PID became so lax in temperature response but it was easily solved.

The other problem of the pump running without shutoff and recycling VERY HOT water to the reservoir tank was not a problem with scale or the OPV valve. For this solution I would like to give my gratitude and heartfelt thanks to Eric Svendson who is an incredible resource for this community and who gives his time and spare parts in a most generous manner. Eric had me isolate the two water lines leading to the reservoir from either the priming valve line or the OPV line using tubing and connectors that I luckily had in my lab at work. Recreating the problem where the pump continued to try to fill the boiler after removing some H2O from the tank showed/proved that H2O was flowing through the OPV and at exactly brewing pressure. The only way for that to happen according to Eric was if the boiler refill valve or solenoid was defective and preventing entry into the boiler. This is an intermittent non-actuation of the boiler fill valve on my machine and after switching the power to the machine on and off several times while allowing it to cool a bit the boiler refill functions properly.

Eric provided me with a complete photo and arrow documented idiots guide to replacing the solenoid which he also by the way mailed me a spare he happened to have around. How nice is that! I have not yet proven that I am an idiot by actually showing I am capable of replacing the solenoid but I am confident that this will solve my second problem. Apparently this is not an uncommon problem with the QM Anita and Chris Coffee even sells a new and upgraded valve/solenoid as a replacement but that is a bit trickier to install.

Many thanks to a great coffee community that even makes problems educational. I have a hugely increased knowledge of how my machine functions and how to take care of it from opening up my Anita and working with her in a productive way - thanks to Eric.

Might I suggest (given EricS permission) that you post the former mentioned online?

-Cecil

I just got around to replacing the boiler-fill solenoid as per Eric's detailed instructions and my (second) problem is solved.

For those with QM Anita's (or perhaps even other QM machines?) if you see symptoms as I described you likely have the same problem.

Here are Eric's instructions.

It is a PITA to replace the entire valve because of working clearance in and around the valve and the fact that QM uses a thread sealant on the fittings screwed into the solenoid valve body.

So, the idea is to replace just the upper half as that is the problem part anyway. With the machine cold, unplugged and undressed:

a. syphon water out of the boiler after removing the copper tubing to the hot water spigot (tilt machine as necessary)
b. remove solenoid coil - keep wires attached or not
c. put some paper towels below valve
d. remove upper half of valve using a 17 mm deep socket (preferably a 6 point socket)

The actual size is 21/32" but a 17 will work -

e. some water will probably leak out of the 1 mm center hole in the valve body (paper towels)
f. Install replacement upper half with NO SEALER - the teflon washer does all the sealing
g. replace solenoid coil - just snug the nut - don't crank down hard
h. replace hot water tubing

TEMPORARILY disconnect one of the heating element leads
Plug her in and boiler will autofill.
UNPLUG machine, reconnect heating element.

She should be good to go.

Photos by Eric available if necessary.

The problem that Geoffrey experienced (and that I experienced a year or so prior) was that the boiler fill solenoid was "sticky" and would not open when a "fill signal" was sent. This would shown by the brew pressure gage easily hitting 8.5 to 9.0 bar when the pump gets activated with the brew lever in the down position. Under these conditions, there is no flow through the group and no flow through the boiler fill valve (stuck closed) - hence the brew gage reads typical blind filter pressures.

While there's probably several ways to get water out of the boiler, an easy (but a litttle long) method is to syphon the water out through the hot water connection on the boiler. This drains the boiler almost bone dry. The nuts and 6 mm tubing you need to remove are shown in the pic below:

The next pic is that of the water tube which extends into the boiler and through which you will insert some 3/16" OD syphon tubing. Other than my pic, you won't see this tube as it remains inside the boiler and does a beautiful job of supporting the syphon tubing.

The next pic shows the fill solenoid valve with the "sticky" valve assembly removed. Remove the upper half of the valve with a deep 17 mm 6 point socket. Other tools can surely be substituted but this lessens the chances of rounding off some brass corners.

Water to fill the boiler flows through the small hole in the center of the body and out the body as shown by the arrow. The inlet to the valve is marked by a "1" and the outlet by a "2".