Rocket Evo V2 plumbed - water pushed into reservoir

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
biobak

#1: Post by biobak »

Hi there,

I've been enjoying my plumed in Rocket Evoluzione v2 for years now. Recently I serviced and descaled my machine. I had an issue with the pump's pressure regulator, which I fixed by replacing the check valve inside the pump (part 13 in the motor's schematic). After that, I descaled the machine using Urnex Liquid Dezcal.



After the descale I noticed that water was being pushed into the reservoir when pulling a shot. This caused the reservoir to overflow after some use. I thought the rubbers inside of the solenoid valves were maybe affected by the descale and that was causing the water to backflow into the reservoir. This seems to not the be the issue however since it's still happening after replacing the cores of the solenoid valves with new ones. Today when the reservoir overflowed and caused the circuit breaker to trip, I noticed the water inside the tank was warm.

My other guess would be that the no return valve (part number 15 in the schematic) might have been damaged by the descale and I need to replace that? This would be just a guess though and considering that my previous guess didn't solve the issue, I figured I'd check with you guys before doing more investments :).



So, anybody have any ideas why water from the boiler is being pushed into the reservoir when pulling a shot?

Thanks!

User avatar
homeburrero
Team HB

#2: Post by homeburrero »

Question: Any chance you, or someone before you, has modified your machine so that the plumbed line solenoid is always open when the machine is on? (Some people do that, maybe by removing the solenoid plunger, to facilitate line pressure pre-infusion with the brew lever in mid position.) If that's the case, and if you have also inadvertently left the machine switched to reservoir mode, then I think you would see flow into the reservoir when brewing.

The check valve #15 in the lower left part of that parts picture (at the top of the plumb line solenoid) is there to prevent flow back into the plumbed water connection, not the reservoir, so I don't think that's the culprit.
Pat
nínádiishʼnahgo gohwééh náshdlį́į́h

biobak

#3: Post by biobak »

Thanks for the reply! I definitely didn't do this mod on purpose, but could be a side effect of me dismantling the solenoids and not reassembling correctly? This was also not an issue before I did the maintenance. I double checked and the machine is set to plumbed mode.

The solenoid should block flow from both directions unless it's energised, correct? So any flow from the main line into the reservoir would mean that the plunger is not sealing correctly? Still wondering how the water that was pushed into the reservoir could be warm though. Hot water is not on the other side of the solenoid right? Or could the thermal conductivity of the machine being on for hours be the cause of that?

I also noticed a new ticking sound when pulling a shot. I thought this could be coming from the pump after replacing the check valve inside. I don't know if this has anything to do with the flow issue.

User avatar
homeburrero
Team HB

#4: Post by homeburrero »

biobak wrote:The solenoid should block flow from both directions unless it's energised, correct?
It's designed to primarily block flow in one direction, so if it gets high enough pressure on the outlet side, that pressure can tend to push the plunger open. That's why you have that check valve between the autofill solenoid and the boiler.

You have another key check valve in your system closer to the pump outlet (#15 near the middle of the parts picture). That one is key to assuring that there is no flow from the HX tubes back toward your pump outlet. If that one is not working I suppose there might be a possibility of flow thru the pump and then the reservoir solenoid back to the reservoir. Seems possible right after the pump stops and the pressure in the HX is still high. And if that's happening the water could end up hot.
Pat
nínádiishʼnahgo gohwééh náshdlį́į́h

biobak

#5: Post by biobak »

Quick update: I reduced the pressure of the mains, figuring it might be pushing the valve open towards the reservoir and this seemed to have solved the issue. Still not sure why this wasn't an issue before. Thanks for thinking along!