Rocket R58 water sensor issue - full tank not recognized

Need help with equipment usage or want to share your latest discovery?

#1: Post by fiksen »

I got a Rocket R58 about 2 months ago. When I first set it up, I filled the reservoir with filtered water from my fridge and turned on the machine. I received the blinking green light and the PID showed empty water tank.

All troubleshooting online said this is caused by RO or distilled water and adding a cup of regular tap water should help.

I'm just using regular filtered water but tried it anyways, to no effect. When I was on the phone with Seattle coffee gear to diagnose, it randomly decided to start working. I don't recall exactly what I did between not working and working, but there was nothing intentional.

Since then the machine has been working fine.

I went on vacation 2 weeks ago, and drained the machine and shut it off. I got back jetlagged last night and turned the machine on so it would be ready in the morning, forgetting to fill the tank. I did hear the pump engage. I woke up and turned it on again (due to calendar schedule) and again heard the pump engage.

Then I noticed the "water tank empty" message.

I've now refilled the water tank however I'm back to where I was on day one, the machine just blinks green and indicates that the tank is empty.

Does anyone know how I can fix this? The tank is now filled and I'm jetlagged and really would like some coffee lol.

Supporter ♡

#2: Post by StoicDude »

Hey, I hope this fixes it.

The sensor for water is in the picture here. It's the two metal screws on the side of the tank. It has a plate on the outside that has to make contact in order to get a reading.

Make sure that the tank is seated all the way in and also that it's making contact on the right side.

Let me know if that worked. If not you ll have to look into it more.

User avatar
BaristaBoy E61

#3: Post by BaristaBoy E61 »

This sounds like a magnetic float in the tank issue an has nothing to do with water quality itself. Check if float moves freely while filling the reservoir in a sink. If that's OK, make sure the reservoir is positioned in the machine such that the float is as close as possible to the stationary sensor built into the machine for that purpose and that the machine, with its alarm, are switched to 'Reservoir' mode.
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

fiksen (original poster)

#4: Post by fiksen (original poster) »

Oh wow, so I was confident the tank was seated correctly and have a photo that appears to show the connectors on the reservoir touching the metal conductors outside of the tank. However after taking the photo, I tried pushing/leaning the plastic tank to the right (ie leaning it into the conductors) and the empty water tank issue disappeared. After letting go of the pressure, it came back. So it appears as though ensuring the tank is correctly positioned doesn't just mean making sure the bottom of the tank properly clicks in, but that it's also correctly up against the pins.

After a bit more jostling, I was about to get it to recognize the water level without needing to push on it. Thanks for the help all!

Team HB

#5: Post by JRising »

Back in the days when I used to fix 4 or more Rockets a week, I would have to completely empty all of the water from the "receiver" (the white cup under the reservoir) before tipping the machine forward to remove the bottom screws (or it would drip on the coil of the 2-way solenoid and pop the GFCI when plugged back in). I found that they would often keep the air trapped in the receiver when the reservoir was pushed into the empty receiver...

Just lifting and re-lowering the reservoir usually breaks the surface tension or whatever causes that air-lock.


#6: Post by jim_reed »

I hdd this problem for a long time. There are two sensors (inside the machine) and two contacts (in the reservoir). The way I solved it was that I put a small wedge between the opposite wall of the machine and the reservoir to press the contacts against, or closer to, the sensors. Haven't had an issue in months.


#7: Post by amateurdad »

The correct fix for this issue (and it is extremely common, speaking as a Rocket dealer) is to remove the contacts and adjust them so they protrude out and make positive contact with the contacts on the plastic reservoir.

I'll send you a PM with instructions on how to do this.


#8: Post by florentine »

Good Morning.

A half hour ago I turned on our appartamento to this same behavior. Usually it just turns on, the green light comes on steady, and the machine begins to warm up. Once in a rather long while when it's turned on the pump will run for maybe 5-7 seconds with a more guttural sound, then stop and warm up as usual. It has done this for as long as we've had it. All other behavior is as expected.

Today I turned it on, the green light came on and the pump began running as if I was drawing a shot. This stopped after a couple minutes and the light started blinking, 3 times and a pause, 3 times... If I lifted the valve it would begin pumping cold water out of the brewhead. It doesn't appear to be heating up but I haven't kept it plugged in.

I removed the reservoir, laid the machine on its side and scrubbed a bit rust/calcification/powder out of the receiver with a dry toothbrush. Also brushed the threaded rod which I think is part of the electrical circuit for the empty tank warning. The screw isn't corroded but does look like something that's been sitting in water a lot. Was considering wiping it with a q-tip dipped in vinegar. Our local Ace has kitchen descaler that contains, I think, citric acid. It's quick.

What else might I try before going to a shop? We live in Denver and I'm pretty sure there's a couple commercial repair entities here. We bought this machine in March, 2020 and it's been great except for a jammed power switch which I was able to fix myself.


Edit: I've added this here only because it's similar behavior as this R58 thread.