Rocket R58 curious hot water issue

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

#1: Post by espressozebra »


I've got a Rocket R58 that has slowly developed a curious issue with the hot water wand, and I'm hoping I can get some ideas on the cause of the issue.

The issue is, when the hot water valves is opened, the wand will only dispenses say 1/2 cup of water, and then the flow just tapers off and stops. At this point I can still steam, still pull a shot, but no hot water until I shut off the wand valve, wait for a few minutes, and then I can get another 1/2 cup - repeat.

I've pulled the wand valve apart thinking a seal had torn or frayed, or something was in the valve, but it is clean. With the machine off, I can open the wand valve and blow air through the valve and hear it bubbling in the steam boiler, so no blockage, at least at room temp.

Note, other than this issue, the machine works fine, i.e. I can steam, I can pull shots, behaves normally. Also, the water in this machine goes through a multi stage & reverse osmosis filter and then through an ion exchange water softener, so, there should be little to no scale buildup.

Anyone have any ideas . . .


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Randy G.

#2: Post by Randy G. »

WAG: If the boiler pressure gauge indicates normal pressure during this declining flow through the wand then there may be some sediment that clogs the feed tube in the boiler which clears itself (through gravity, heating convection currents, or ??) when the valve is closed.
Espresso! My Espresso! -
LMWDP #644


#3: Post by espressozebra »

Hey, thanks for the "WAG". Boiler pressure gauge stays up, I can steam and pull a shot while this decline occurs, but I think your intuition about a clog is on target. Because the flow from the wand starts out strong and then wanes quickly, I am now suspecting that it is a restriction in the water supply to the boiler. I'm plumbed in, so it should be seeing ~ 40 psi at the inlet, so maybe just enough restriction to let water flow, but not enough to keep up with the wand. Maybe time to pull the inlet solenoid and have a look. BTB, liked your blog, err website.


#4: Post by JRising »

What I am thinking is that the rubber valveface in the valve is actually coming out of its holder. Water behind the rubber heats to a boil with the passing steam and unseats the valveface from the brass. It happens to brew valves when the rubber gets weak enough, even with the cam-riders and tiny washers trying to hold them down. It could potentially happen to a steam/H2O valve. You could swap valvestems with the rubbers from left to right and see if the issue moves with the valvestem, this could rule out an issue with the pipe clogging.
See if the rubber comes out easily, dry the valve really well, put the rubber back, possibly with a little RTV behind it to hold it in the valve.


#5: Post by espressozebra »

Thanks for post! What you say makes sense though as it seems like just leaving the valve open doesn't eventually produce additional flow, I have to shut the valve - caveat, I've not tried leaving it open for 5 -10 minutes to see what happens - so that would seem to bolster the idea that the valve faces is blocking flow.

I did pull that valve apart, and it "seemed" OK, but I didn't have anything to really base that on other than no apparent damage. I'll pop it open again and look a more closely. Given the similarity in the appearance of the H2O and Steam valves, I may be able to swap the seal from on to the other to test.

Thanks again, I'll post back once I give this a try.

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BaristaBoy E61

#6: Post by BaristaBoy E61 »

How old is this machine?

Has it ever been completely descaled with a citric acid flush?

Sounds to me like that might be what's called for here.

"You didn't buy an Espresso Machine - You bought a Chemistry Set!"


#7: Post by JRising »

espressozebra wrote: I may be able to swap the seal from on to the other to test.
Swap the entire valvestems from each side to the other. If one of them is not having problems, don't pry out the rubber and potentially give it a problem.Image


#8: Post by espressozebra »

Hi JR,

Thanks for the suggestion, makes sense to try to not make things worse.

@BaristaBoy, the machine was acquired in 2013, so 7 years old, but has been run on RO water w/ downstream ion exchange, so there should really not be much scaling.