Re-Setting the Height of the Water Uptake Assembly for v1.3 (and v1.0/1.1) Machines to Achieve the Most Accurate Water Level Reading Possible
Quick and dirty video to help v1.0-v1.3 folks showing a low water when the tank is still half full, or more. Read below first. Then, watch the video and refer to the guide below.
A quick explanation of the "water level reading", which is actually taken by an air pressure sensor. Initially this was not meant to be a user visible feature, simply something to tell the FW that the tank was "empty" once the air pressure inside the air column was equal to the pressure outside. That would have triggered the refill kit to refilll, or a prompt on the app screen to ask the barista to refill the tank. However, John realized that the positive air pressure differential reading coud be converted, roughly, to "see" the water level in the tank, and thought it would be a neat feature to add for users to make the experience a bit more rich. Roughly being the key, here, and with come further caveats. There are a couple things that make this reading tough to nail down, please read on:
1. first and foremost, the air trapped in the pressure sensor air column has a couple ways to slowly bleed out. Again, as it wasn't originally intentioned to be a high resolution reading, but rather an "empty" or "has water" readin, so originally this was not a problem. Additionally, each time a tank empties, and is subsequently refilled, the air column pressure differential rises again, and the sensor is reset. However, that doesn't always happen now, especilly if a refill kit is being employed, and the setting never allows the tank to empty completely. In this secnario air can slowly bleed from the junction of the silicone hose that joins the barb at the top of the air chamber to the barb on the air pressure PCB, and the app interprets this lowering pressure differential as a drop in water level. The way to combat this is to occassionally lift the water uptake assembly, hold it out of the water for 5-10s, and then lower it again. The air column is now filled, and the air pressure sensor is now reset.
2. set height of the bottom of the uptake tubes relative to the bottom of the tank is key. if the uptake tubes are set a bit high, which has happened from the factory from time to time, then the pressure will read low before the tank is truly empty. Luckily, setting the tube at the proper height is an easy adjustment, and I will pop a video up here showing the prodecure.
3. The tank themselves, being ceramic, and thus organic, have a relatively wide tolerance range compared to stamped metal, for instance. So, some of the bottoms are a bit deeper, some are a bit shallower, but the vendor sets all the uptake assemblies at the same height. This means that a deeper tank will have more water left in it, compared to a shallower one when the sensor reads "empty" (which is really pressure equilibrium) even though the same amount of water has been drawn from the tank. Users are always welcome to adjust their uptake column down a bit to compensate for a deeper tank.
4. Heat affects the air pressure reading, and also makes it easier for air to bleed from the air column. This is especially true if you're using tank preheat, which you can set to preheat the tank as high as 60c. The solution here, as in 1. above, is to reset the sensor occasionally by lifting and lowering the uptake assembly.
So, now that you're done with that, please check out this video and have a go at resetting your uptake. Please watch the video all the way through before commencing the work on your own. Then, start the work and start and stop the video as you go.
Here is an easy-to-follow guide on how to adjust the height of the tubes in the water uptake assembly (water level sensor calibration) for your Decent Espresso machine, based on the video:
Tools and Materials Needed
T10 Torx screwdriver [00:17]
2mm hex key (driver type or standard L-key) [00:50]
Fine-tip marker (e.g., Sharpie) [00:44]
Two standard plastic cards (e.g., credit cards or membership cards, preferably unembossed, to create a 2mm spacer) [01:10]
A small parts bowl (for screws and knobs) [00:38]
Paper towel or rag [02:10]
Your water tank (removed, emptied, and cleaned) [01:25]
Step-by-step guide
1. Remove the outer cover
Using your T10 Torx screwdriver, remove the four screws on either side of the machine's cover [00:08].
Slide the cover forwards or backwards to remove it completely [00:26].
2. Remove the uptake knob and filter
Lift the water uptake assembly slightly. Hold the tube with one hand and unscrew the uptake knob with your other hand. Place the knob in your parts bowl [01:41].
Pull the water uptake assembly up as far as it goes. Remove the thimble filter from the bottom of the water uptake tube [02:04].
Note: Have a rag ready, as breaking the vacuum will cause some water to spill out [02:10]. This is also a great time to thoroughly clean the thimble filter to prevent pump pressure issues [02:24].
3. Loosen the tubes
Carefully move the silicone feed tube out of the way and rotate the uptake assembly 90 degrees so you can easily access the grub screws [03:28].
Using your 2mm hex key, loosen the four grub screws holding the tubes in place until the tubes can slide freely up and down [03:53]. Leave it resting in this position [04:13].
4. Set up the 2mm spacer
Take your two plastic cards and place them flat in the bottom of the empty water tank, specifically in the right-hand rear corner where the water uptake assembly enters [04:18]. This creates the exact 2mm clearance needed.
5. Mark the correct height
Swivel the loosened uptake assembly back into its normal position and lower it down into the tank [04:41].
Briefly screw the uptake knob back in to establish the slider body's minimum height [05:01]. The tubes should be resting flat against your plastic cards [05:09].
Take your fine-tip marker and draw a line on both metal tubes exactly where they meet the top of the slider body [05:39].
6. Secure the tubes
Remove the uptake knob again and swivel the assembly 90 degrees to access the grub screws [05:55].
Slide the tubes until your drawn marker lines perfectly align with the slider body.
Tighten one grub screw on the water uptake tube, then tighten one on the air uptake tube [06:17]. Once the height is locked in, tighten the remaining two screws. Do not overtighten; just make them hand-tight (about 1 to 2 newton meters) [06:42].
7. Reassemble and test
Reattach the clean thimble filter to the bottom of the water uptake tube [07:26].
Remove the plastic cards from your water tank and slide the tank back into the machine [07:07].
Carefully lower the water uptake assembly while holding it, screw the knob back in, and gently let it drop to its lowest position [07:36].
Final check: The tubes should drop down deep into the tank but you should not hear them hit or scrape the bottom of the ceramic tank [07:46]. If they hover just above the bottom without touching, your calibration is perfect and will allow for maximum water drawdown [08:11].
#repair #howto #DIY #documentation
