Hi folks,

My 2 year old Quickmill QM67 has been working great until recently when the pressure won't hit 9 bars for almost 15-18 seconds.. I tried using a blind basket and the pressure hit 10 bars only after about 14 seconds. It used to reach the 10 bar pressure within 6-8 seconds in the past because I'm used to doing 10 second backflushes when cleaning with Kafiza.

Basically, when I pull a shot, nothing comes out for almost 15-16 seconds. whereas in the past, I'd get the first drop anywhere between 6-10 seconds. And I know that its not due to ground size being too fine because I have tried going coarser but its mainly because the pressure is stuck at 3-4 bars for a looong time before ramping up to 9 bars.

I cleaned my group head to ensure that there's no blockage. Also, since the machine hits the 10 bar pressure with blind basket, I am told that the pump is working fine. If the pump is broken, then it would never reach 9-10 bars. Am I mistaken?

Please help me out, thank you so much!

Prashanth

I'd agree that the pump is OK.

Sounds like a clogged flow restrictor (gicleur) to me.

Pardon my ignorance but what does this mean? What should I check in the machine? thank you!

vecchi della seattle wrote:I'd agree that the pump is OK.

Thank you for reassuring. Any idea what could be causing this issue? Could it be the water? Its been two years that I've been using regular filter water at home. Never tested hardness. Should I switch to bottled water or something?

How can I find out if I need to descale my machine? Thanks again for all your inputs and advise.

It sounds like your brew circuit is leaking internally. For example, picture the brew boiler heating past boiling temperature. The brew boiler doesn't have a vacuum breaker, it's supposed to be sealed by the check valve up-stream and the brew valve downstream. Now imagine one of those valves leaks internally, the boiler is trying to turn the water to steam, there's a leak, so the steam can continuously expand and either escape as steam or displace the water out of the brew circuit through the leak.

Where are you measuring the pressure? If the gicleur were blocked everything downstream from the gicleur would have the waterflow to it blocked and thus not reach pressure quickly, but everything up-stream of the blockage, like the machine's gauge for the brew circuit and everything, would show a very high pressure.

Likely leakages that the water could be escaping would be over the brew valve... If you run the pump with the brew lever down (put a spoon behind the cam or something), do you see the water escaping over the brewhead or the E61's drain? If so the brew valve (uppermost in the brewhead) is leaking when closed.

Possibly leaking over the brew circuit's check valve. Does the outlet pipe from the pump feel hot when the machine has been idling for a while? It shouldn't, if it is hot the brew-circuit's water is flowing backward through it, clean/examine/replace the check valve.

It could be as simple as the expansion valve doesn't seal well anymore. You might see this with the top off of the machine as movement in the clear silicon tubing, or a constant dribble at the tube that drips into the tray (if it drips after the machine is fully heated and idling, it could be internal leakage over a valve).

When the water is escaping the brew circuit at idle, it then needs to be replaced when you start brewing, that takes several seconds. That's why it takes so long to see the first drops on your first shot after time idling (If I understood your dexcription of the issue). Once it does start flowing, the flow should be as much as you're used to. That too will prove that it's not a clog.

If it does turn out to be a clog, the gicluer in your machine is under the small upper hex-nut on the e61 head. If you look in there you'll see a cylindrical mesh filter around a tiny brass hex at the bottom of the chamber. In the middle of that brass hex is a 0.6mm or maybe 0.9mm hole through which the water can travel down to the brew-head. That's the gicleur, you can poke through it with a 'welder's tip-cleaner" or a needle or a thin wire.

Prashanth13485 wrote:Pardon my ignorance but what does this mean? What should I check in the machine? thank you!

I don't have your machine, generally the "gicleur" is a flow restrictor (does exactly what the name suggests), most espresso machines have one.
The closest I could find to your machine on a quick search is this article from Clive Coffee:
https://clivecoffee.zendesk.com/hc/en-u ... r-Blockage
Yours may have the same gicleur design.

Thank you so much for the detailed response. I'm going to have to go through it slowly and follow your instructions. If its not already obvious, I'm not very technical.. haha..

I am going by the display on the machine that shows the bar pressure as well as steam pressure. Since its not showing high pressure, is it safe to conclude that its not a gicleur blockage? Thanks again for being patient with me. And sorry if I am not grasping this properly.

JRising wrote:It sounds like your brew circuit is leaking internally. For example, picture the brew boiler heating past boiling temperature. The brew boiler doesn't have a vacuum breaker, it's supposed to be sealed by the check valve up-stream and the brew valve downstream. Now imagine one of those valves leaks internally, the boiler is trying to turn the water to steam, there's a leak, so the steam can continuously expand and either escape as steam or displace the water out of the brew circuit through the leak.

Where are you measuring the pressure? If the gicleur were blocked everything downstream from the gicleur would have the waterflow to it blocked and thus not reach pressure quickly, but everything up-stream of the blockage, like the machine's gauge for the brew circuit and everything, would show a very high pressure.

Likely leakages that the water could be escaping would be over the brew valve... If you run the pump with the brew lever down (put a spoon behind the cam or something), do you see the water escaping over the brewhead or the E61's drain? If so the brew valve (uppermost in the brewhead) is leaking when closed.

Possibly leaking over the brew circuit's check valve. Does the outlet pipe from the pump feel hot when the machine has been idling for a while? It shouldn't, if it is hot the brew-circuit's water is flowing backward through it, clean/examine/replace the check valve.

It could be as simple as the expansion valve doesn't seal well anymore. You might see this with the top off of the machine as movement in the clear silicon tubing, or a constant dribble at the tube that drips into the tray (if it drips after the machine is fully heated and idling, it could be internal leakage over a valve).

When the water is escaping the brew circuit at idle, it then needs to be replaced when you start brewing, that takes several seconds. That's why it takes so long to see the first drops on your first shot after time idling (If I understood your dexcription of the issue). Once it does start flowing, the flow should be as much as you're used to. That too will prove that it's not a clog.

If it does turn out to be a clog, the gicluer in your machine is under the small upper hex-nut on the e61 head. If you look in there you'll see a cylindrical mesh filter around a tiny brass hex at the bottom of the chamber. In the middle of that brass hex is a 0.6mm or maybe 0.9mm hole through which the water can travel down to the brew-head. That's the gicleur, you can poke through it with a 'welder's tip-cleaner" or a needle or a thin wire.

One possibility, since the QM-67 is an e61 machine, is that the infusion chamber (the cylindrical bit situated below the brew lever) that controls by means of a spring the rate of rise of pre infusion pressure is not working correctly. Could be a faulty spring or bad seals.

If not mentioned before, maybe the priming valve of the pump still release water a bit longer than normal.
Going to the water reservoir there are 2 silicon pipes, the one without the plastic filter at the end is a pipe connected to the OPV and to the priming valve, if once you lift the group lever up, to activate the pump, you can see water flowing out from that pipe continuously from the beginning, visually is probably difficult to realize if the water is from the priming valve ( normally until 5-6 bars) or from the OPV from 10 bars as you set it.
I'm not a master in explanation