EM6910 - Lower steam pressure at lower water levels.
My EM has been a loyal servant for the last 9 years. Had it's first trip to the repairers after I attempted a collar change and in typical fashion, one screw was stripped and unable to be removed. Other than that, it hasn't skipped a beat.
Since coming back from the shop (probably six months ago now), I noticed the steam pressure seemed down. Texturing milk was much harder and took longer. I took it back to them and mentioned the problem but they reckoned the steam pressure was good. Now I will rarely have more than a litre of water in the reservoir but have noticed that since the repair, the steam pressure is almost back to what it was when the reservoir is full.
Is this perhaps the steam pump on it's way out and needing the pressure of a higher water level to feed it properly?
Hi, don't really know mate , mine had the thermo block replaced after 5 years and that fixed the pressure issues
It's an interesting suggestion you make about water level affecting the steam pump operation.
I recently had a look at a mate's 6910 as he could not get the steam pump to prime. Operating both pumps at once got some action from the steam but it was weak and intermittent and would not restart after a short pause. From memory the level in the water tank was fairly low.
I even pulled the pump mechanism apart but it all seemed OK so I just swapped it for the mechanism I had from a burned out pump and it then worked well.
Coincidentally, my own 6910 steam pump has been a bit temperamental in starting for quite some time but has got much worse lately, as have the complaints about it from the operator, so I have only just finished replacing it with a new one. A quick test following the swap seems to show a remarkable improvement - can't wait for the after-work coffee to see how it goes.
Originally Posted by willsy01
If you are comfortable opening the machine up, it sounds like a poor connection to me. A quick clean of the various contacts or even a spray of non-residue circuit cleaner at random (if you do not know what you are doing) should improve it. The last one I opened had a slightly corroded contact - a ten second clean and all was well.
Pumps typically have a minimum required suction pumping head - this is to ensure water flows into the inlet fast enough to keep up with the pump (and prevent cavitation). However, the 10cm or so you might gain by filling the tank is so small as to almost be irrelevant, so it seems hard to imagine that being the cause unless there is some restriction in the pump inlet.
That said, my Bezzera is certainly a lot quieter with a full tank - but I haven't determined whether it's actually due to extra suction head or if it's just dampening the vibration.