Rocket R58 brew pressure problems.

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Tony77

#1: Post by Tony77 »

Hello all,
I've had a Rocket R58 for 3 years now and it's been great. Lately, a few things have begun to creep up and now I'm having a few issues. Most notably:
I was finding way too much water in the drip tray after I pulled a shot. I discovered lots of water flowing from the overpressure exhaust every time I pulled a shot (the shot was also cold and blonded very early).

- When I pull the shot the pressure gauge hits 10 bar, after a second or two it climbs to 12 bar. As the shot begins to pour a large amount of water spurts out of the overpressure exhaust

- The machine used to hold steady at 9 or 10 bar and the shot would eventually begin to drip (or sometimes not if the grind was too tight); it never "kicked into overdrive" as it does now and I never saw this much water flow from the OP exhaust.

- When I backflush with the blind disk, the same thing happens: pressure holds at 10 bar for a second or two, peaks at 12 or 13, water flows from OP exhaust. This never used to happen.

- I took a peek inside, everything looks fine, no leaks, hoses and connections look good.

Could this be a faulty overpressure valve? Do I need to descale?

Any help would be greatly appreciated,
Thanks!

Tony

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erics
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#2: Post by erics »

The problem lies with the pressure regulating valve inherent to the rotary pump. It is apparently sticking closed. You need to remove it from the pump and clean as necessary.

Image

Items 13-22 are the applicable offenders.
Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

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erics
Supporter ◈

#3: Post by erics »

After this is accomplished, insert the blind basket and adjust the pump pressure to 12.0 bar. Adjust (or not) your OPV such that the drip tray shows a drip . . . drip . . . drip.

Back off the pump's pressure regulator a couple of turns and reinsert the blind basket. Now adjust the pump to 9.0 bar and you are good to go.
Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

Tony77

#4: Post by Tony77 »

Many thanks for your response! Two questions:

1. Do you think replacing the pressure regulation valve all together would be better than cleaning it? Or does a cleaning usually solve this problem?

2. I've never done anything this intricate to my machine, however I am pretty handy. Would you recommend taking this to a shop or is it easy enough for a novice?

Thanks again,
Antony

User avatar
erics
Supporter ◈

#5: Post by erics »

Please post the make and model of your pump.

This is one of those cases where an inspect and act is the best course. After cleaning, lube the O-rings with a light film of plumber's grease or Dow-111 (preferable).

Then adjust as previously advised . . . any questions . . . give me a call at 301-587-5033.
Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

Gethin

#6: Post by Gethin »

Hi,

My three-year old Rocket R58 has been suffering the same issue as described above... Brew pressure mounts from initially 10 bar to 15 and pours water from the overflow valve at the front. I cannot reduce the brew pressure any less (even removing the brass nut completely from the bottom of the machine has no effect).

Erics seems to have posted a solution, but my question is how to remove the rotary pump (I presume I need to remove the whole thing from the machine to inspect and clean the o-ring...? The water in Copenhagen is quite hard.

Thanks in advance!

JRising

#7: Post by JRising »

The pump can be removed by disconnecting both water-connection fittings, then loosening the bolt on the collar(27 in the picture above) that holds the pump to the pump-motor, then simply pull the pump away.
If the angle is good, you can take the relief bypass (parts 13 through 20) with the pump in place. Just hold the pump securely so that you aren't stressing the water connections terribly working on it.

Gethin

#8: Post by Gethin »

Thanks JRising! Making progress and have removed the pump to clean the first part (looks like there is some gunk on the first parts.

I need to take out the open valve (part 13) but it doesn't seem obvious how to remove this - any advice?

JRising

#9: Post by JRising »

It should just slide out. Somebody correct me if I'm wrong... If you're working with the pump still connected maybe atmospheric pressure is holding it in slightly against a low pressure at the pump outlet, if you can reach the back of the pumpmotor maybe turn it to move a bit of water and air from the vanes into the outlet.
If it's sticky, then I think you've found your pressure issue. Be gentle, stick something into it and pull, it really should just slide.

Gethin

#10: Post by Gethin »

Thanks JRising,
Yes it was stuck - had to take it to the local shop and he drilled it out and put a new one in. I was looking forward to firing up the machine, but now reconnecting the pump to the motor is very difficult! I can't align the coupling (#26) without it slipping when I re-attach the pump to the motor. Do I have to disconnect the whole motor unit to reattach the pump or is there a good tip as to how to reattach it?

Thanks.

G