Some BS010 Viton O-rings, from the FAQ on Lelit’s Flow Control Valve (thanks DavecUK ) - they seem to be the correct size for Coffee Sensor’s flow control device as well (the green O-rings in the picture are the ones that came with the the Coffee Sensor device. The blacks are new).
Doram Excellent, I have updated the blog article on the forum. I think there is a general lack of knowledge out there about the regular maintenance and O ring replacement requirements of these flow controls.
DavecUK Excellent, I have updated the blog article on the forum. I think there is a general lack of knowledge out there about the regular maintenance and O ring replacement requirements of these flow controls.
In the first picture it is easy to see that the O-ring (especially the bottom one) has degraded significantly. The device is exactly one year and one day old, but I noticed degradation (cuts and bruises) on the O-ring the first time I opened the device to lube it on your advice, and this was only a few days from new. I hope that after this first lube I have learned to avoid opening the valve beyond a certain point, giving the O-rings an easier life. Before that, in the first days, I experimented with opening the valve to see what’s the max flow I get. In doing this I think I pulled the O-rings too deep into the barrel, and that may have been the cause of cuts in the O-ring. As it’s not necessary to open the valve so much I have learned to not do it, and that seemed to work fine. I didn’t replace the original O-ring until today, and the device worked fine as far as I know. In any case, as you said in the FAQ, now I have supply for an annual change of the rings for the next 25 years (26 with the spare greens I still have).
Doram It’s great that they do free postage, it would be irritating to have to pay an extra £4 for P&P
DavecUK xcellent, I have updated the blog article on the forum. I think there is a general lack of knowledge out there about the regular maintenance and O ring replacement requirements of these flow controls.
DavecUK The following message would probably be more effective as a reply to your FAQ post (but there is no reply option), or as a new thread. I leave it up to you to move wherever if you see fit:
I just pulled the first shot after servicing the flow control device and replacing the O-rings and I was completely shocked by the result. Not only was the action of the valve so much smoother, I was actually able to control the flow completely, stop it, hold the pressure where I want it and get instant reaction from the manometer - all things that I was NEVER able to achieve before!
Until today, when I tried to almost close the device for pre-infusion a few seconds after lifting the lever, I could slow the ramp up a little, but that was about it. Then when I would tale off the pressure to end a shot, there was a delay in reaction and I would usually go down to about 6 bar to end the shot. I saw videos of people holding pressure for long periods (at 2-4 bar for example). In those videos, manometer reacted instantly to closing/opening of the valve. Mine didn’t do that, and I just assumed that my machine/flow control device are ‘different’. What a fool I was! I now realise that when I first got the device I damaged the O-rings by opening the valve too much. The valve probably never sealed completely since then, so I was only able to make small changes to the flow, but not control it completely. With the new O-rings and some lube, I finally get to play with the flow control device as it should be (I hope I am not getting carried away here - this was just one shot and I still have to play and confirm the above, but couldn’t resist sharing already). For anyone who is as stupid as me, your FAQ is priceless.
I added it, as the nature of the blog section (function), is to create a reference article. Something I intend to do more of as things get solved on the forum. As always the problem is time.
Busy day - New heater for Gene Cafe, a Rocket naked PF (didn’t need it really) and some green beans:
BWT
And the Halo best espresso 2022 Helsinki coffee weekend by the Best Finnish coffee roaster 2022.
Makea ( Sweet in Finnish) Coffee
(
A few bags of beans roasted in northern Sweden by Budha.
This is the only link and are the best ones to get as they are Viton, I advice buying a 50 pack. They are not used anywhere else to my knowledge.
DavecUK lovely, thanks. I performed some maintenance on my Bianca the other day for the first time since buying and found it fairly straightforward. I followed the longer video and took all the bits apart, bar the flow profiler (I ran out of time). I only found myself lubing the odd thing line the cam pin with the kidney shaped end bit. I expected to lube other bits including o rings, but the o rings on the Bianca are plastic so I assume they don’t require it?
BigTTony The white rings are teflon, I always put a smear of lube on them for luck.
DavecUK that also helps, thanks. Maybe I was just poised with the molykote and wanted to lube more than I expected to! Thanks for the advice. Whilst I’ve got you, can I ask a quick question about the dosing funnel I bought? It leaves a 1-2mm ‘edge’ around the portafilter post distribution and I’m wondering whether this is frowned upon because it causes an uneven surface and might contribute towards channeling. I’m considering buying a dosing funnel without any lippage inside the basket, but wanted to ask someone in the know before considering my options. Thanks in advance.
I wouldn’t worry about the small lip from the dosing funnel, just bump portafilter with heel of hand to level.
I bought the O-rings from the link in Dave’s FAQ post: https://simplybearings.co.uk/shop/p512590/BS010-1.78mm-Section-6.07mm-Bore-VITON-Rubber-O-Rings/product_info.html.
Maybe you are getting confused because the picture shows bigger rings? I think it’s just a generic photo they use of an O-ring, not the actual product. What’s important is the size: BS010 (the measurements of it are 1.78mm Section 6.07mm bore).
