I've been getting a maximum of 6 bar brew pressure on my Synchronika no matter where I adjust the pressure screw on the pump. Problem started several weeks ago, and was getting a small puddle of water under the machine. I removed the covers and discovered the dreaded melted t-connector on the drain lines, so I replaced the connector with a brass t, turned the machine back on and I'm still only getting 6 bar brew pressure. Steam Pressure is great -- no problem. The brew opv line seems to leak. I have the "new" unadjustable style opv valve. While I see alot of info on removing and cleaning the vacumn valve and overflow on the steam side, I don't seem much info on the opv valve at the pump. Do these go bad? Does that sound like what the problem is?

Should I try removing and cleaning the anti vacuum valve on top of the steam boiler and reassembling that? Could that have something to do with it? Any info appreciated.

It has nothing to do with the melted Tee; that's got to be coincidence. It has nothing to do with the anti-vacuum valve; the steam and brew circuits are totally independent.

How much is this brew OPV line leaking? It would have to be a lot for that to keep the pressure down. Still, there should be no leaking, as that valve is basically a safety device that only opens on too high brew pressure (~14 bar I think). Sorry, my valve is the old, adjustable type, so I have no suggestions there on how to service it.

I suggest that you eliminate the bypass circuit on the pump as an issue. They reportedly can get sticky, although I've never had an issue. I understand the solution is to run the pressure valve all the way closed, run the machine a bit, open it all the way, run the machine a bit. Repeat a few times.

Nunas, thank you for this advice. I've replaced the T with a brass t, also replace the OPV valve on the steam boiler (the small rubber gasket had deteriorated). And all is working pretty much as designed no leaks etc EXCEPT I'm still not able to get my brew pressure up. The fixed 14bar OPV on the brew boiler is not opening at all that I can see. And still, adjusting the brew pressure screw on the underside of the pump does nothing. Are you suggesting tighting that screw all the way in, then running for a while, then reverse, running it for a while etc....do you think that will resolve the pressure issue?

pwhinson wrote:Are you suggesting tighting that screw all the way in, then running for a while, then reverse, running it for a while etc....do you think that will resolve the pressure issue?

You're certain, by the way the gauge moves, that it's not a fault with the gauge, correct?
I would suggest not tightening it unless the pump is running and you're watching the gauge. Setting it randomly, then running the pump could result in a very high pressure spike to the system.

You should be able to make the pump run with a spoon behind the cam. You can have a look to make sure there's no flow escaping the brew circuit anywhere like the brewhead, drain or expansion valve, and check the gauge. If it's lower than 9, start adjusting the pump relief bypass screw tighter while watching the gauge. If you get anywhere near "all the way in", that is worrisome, all the way in is a very high pressure. The pressure should rise pretty much in time with your adjustments. If it doesn't, try backing the bypass screw out several turns. It is of course possible to unscrew it all the way and you don't want to do this while the machine is pressurized, so stop unscrewing when the screw feels completely completely free to turn in both directions, and start re-tightening.


And, as a totally separate topic, if your vacuum breaker valve is still hissing, then yes, you should clean it or replace it. It was probably the constant steaming from the vacuum-breaker that destroyed that plastic Y-fitting.

pwhinson wrote:<snip>Are you suggesting tighting that screw all the way in, then running for a while, then reverse, running it for a while etc....do you think that will resolve the pressure issue?

OMG, no! I fear my prose was far from precise. Yes, turn it in and out and run the pump, but not for a "while". By "a bit", I just meant to run the pump for a very short time to flush out any debris. John's suggestion to turn the control in and out while running the pump is probably better. Also, don't put a blind basket or grinds, just an empty group. The intention isn't to build any pressure in the system, only flush. Sorry for any confusion

I think John makes a good point about the status of the brew pressure gauge. It could be stuck and unable to register above 6 bar. Another thing to consider, besides the pump's ability to generate adequate pressure is that there are other factors that can limit the maximum pressure achievable in the brew circuit, some of them in the e61 circuit itself, including leaks from its supply tubing. If your e61 is equipped with a FCD you can check the brew chamber pressure with a gauge on the group head...and even if not so equipped, you can attach a pressure gauge to the port on the "nose" of the e61.

pwhinson wrote:I've been getting a maximum of 6 bar brew pressure on my Synchronika no matter where I adjust the pressure screw on the pump..

I'm going to start again from the beginning... I wonder if this thread is turning into a very miscommunicated miscommunication.

You are talking about 6 Bar "Pump Pressure" on the pump gauge when you're adjusting the Pump bypass screw that pokes through under the machine, correct?

Not talking about the gauge at the grouphead measuring pressure-drop across the coffee-prep as you increase or decrease flow through the gicleur with the flow control valve on the grouphead. Pressure at the gauge below the flow control will always be lower than the pump pressure gauge so long as there's flow. I think I'm getting off on a tangent, now. I hope we're not miscommunicating your actual issue.

(1) So yes I'm talking about 6 bar pressure on the brew gauge. This is the pressure that's being read from what I'm calling the brew gauge (the one on the right as opposed to the steam pressure gauge on the left). The small gauge looped copper tubing that leads to this gauge goes directly to pump I believe.

(2) I actually DO have the FCD device installed with the gauge over the brewhead. Just FYI, that gauge is reporting the same sub 6 bar readings. I'm aware that its natural for that gauge to vary from the brew gauge a bit but in this case they are showing the same pressure when trying to brew a cup, with the portafilter loaded. That FCD valve is working as it always has although I rarely use it and normally run it wide open, i.e. I don't attempt to pressure profile my shots.

(3) I have tried just flushing the system with an empty portafilter, I've done a few standard water backflushes with a blind portafilter. All to no avail with regard to having any effect on the pressure.

(4) WITH REGARD TO THE ADJUSTMENT SCREW. I haven't tried turning the adjustment screw much but its clear that any amount of turn on that screw up to say a full turn which I've tried, then backing it back out, has no effect on the pressure at all. I've been making those adjustments with the machine running during a normal 10 second water backflush with a blind portafilter basket.

Also just FYI on the steam side, YES as I said before I did end up replacing the vacuum valve on the steam boiler...but as you said...separate system.

You can ... as you know ... also run only the brew side by turning the steam boiler off altogether in a switch below the drip pan. When I do that the steam boiler is of course entirely quiet and you're better able to "hear" or observe what would be I assume leaks in the brew system....and I don't HEAR anything and I don't see water escaping the closed brew circuit anywhere, and there's no water escaping through the OPV valve on the brew boiler.

Just low brew pressure.

Does that help clarify some of the confusion? Also this is a machine that's about 2 years old I think. It has worked reliably, has been used daily for probably four mostly Americanos and an occasional shot and occasional milk drinks. But mostly just pulling shots and making a few Americanos every morning.

Yes. That clarifies it and brings me back to assuming everything assumed before I jumped to the miscommunication conclusion. I wish I could just see/hear/feel it.

Assumptions that I am making include that the pump sounds normal, so it probably isn't blocked upstream, however checking that there isn't an obstruction in the little plastic inline filter wouldn't be a bad idea.

So that leaves me strongly believing that your pump bypass is constantly relieving at too low a pressure.

I'm going to suggest trying to adjust it up with the pump running, either against a closed brew valve (with a spoon or something behind the cam) or with the blind basket in place to see if you can get it to work. After a couple turns tighter you should be seeing a change on the gauge. You should feel the tension against the spring inside making it a little harder to tighten as you get tighter. Be ready to flick the spoon out or bring the lever back down while doing this as the bypass valve could free itself up under the increasing spring pressure and the pressure could jump suddenly. If after 4 full rotations there's no change, my assumption is that there's something seriously wrong with the bypass valve or the pump itself.

The bypass valve can be removed from the pump and inspected, re-greased or rebuilt, if you can find the right supplier of rebuild kits for exactly that pump.

Let us know your results.

So with a blind basket/portafilter installed on the grouphead and the machine running, the pump works obviously but tightening the screw then backing it down yields no change in pressure. AT ALL. No matter how many turns up or down. Can you clarify what you mean by bypass valve? I assume you're not talking about the 14bar over pressure relief valve?