Machine overpressuring

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

#1: Post by deverett »

I have just joined the forum mainly because I am having a problem with my machine - a Rocket R58 that I have owned for about 10 years and hope someone can give me a clue as to solve my problem.

Over the past few months when I pull a shot, the pump pressure has been steadily increasing. Normal pressure is up to 10 bar, but now it is reading 17 bar regularly.

I backflush the machine on a regular basis and have stripped and cleaned the group head several times so that I could almost do it blindfolded! New parts have been installed from a rebuild kit. The last time I stripped the machine down, I also stripped and cleaned the bypass valve on the pump. At least I think I stripped the bypass valve. The nut was removed and the spring came out, also a black adjuster fitted into a brass body. Deep inside the valve body is a small stainless steel spring (I think). It looks quite delicate so did not try and pull it out. The valve was reassembled with the adjuster at minimum pressure but this did not affect the pump pressure.

Does anyone have any suggestions on what can be causing the over pressuring?

The Emerald Isle

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#2: Post by Nunas »

If turning the bypass adjustment does not change the pressure, then chances are there is a bit of crud in it, or it was not reassembled correctly. You may find some information here in the Fluid-o-tech rebuild manual ... ctions.pdf

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#3: Post by stefano65 »

If your gauge is accurate 12 bar should be the opening point of the OPV for plumbed in machine,
I will make sure that you are lowering it at least that,
17 bar might (can, will, could) crack your Heating Exchanger.
Stefano Cremonesi
Stefano's Espresso Care
Repairs & sales from Oregon.

deverett (original poster)

#4: Post by deverett (original poster) »

Thanks for the suggestions.

The machine is not plumbed in, I use the built in tank. The normal operating range for Rocket machines is between 8 and 10 bar. I am trying to find out how to reduce the pressure, that was the point of the original question.

You may be right, Nunas about a partial blockage in the pump.. I have downloaded the pump overhaul document and will give that a good read before trying any dismantling operations!

The Emerald Isle