Flair 58 mid-shot pressure drop

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JonTheFisherman
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#1: Post by JonTheFisherman »

Hi all, just got a Flair 58 last weekend - I've had Bianca and Decent recently. I see a lot of potential in the 58 and I am still getting used to it. For the time being, I am just doing 5-8 seconds of preinfusion at 2 bars and than ramping up to 9 and holding there until the end of shot. I am still not comfortable enough to do more pressure profiling than that. But there is one thing that happens mid-shot that I am not sure to what it is due. I am able to keep pressure more or less stable on 9 bar and I am feeling well the puck resistance but about half-way down, suddenly I feel sort of a "shift" in the position of the valve, resistance drops and lever goes lower faster and the pressure goes down to 5 bars. Right after this "hick up", I need to readjust my pressure and then I can get back to normal 9 bar and finish the shot. Anybody else have experienced a similar thing and can venture what it is due to and how I can fix it? If it helps - I am using a Niche Zero grinder with the Flair low flow stock basket (with the walls slanted towards the bottom).

ab
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#2: Post by ab »

I have this same issue and would love to know if there is a fix for it.

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Brewzologist
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#3: Post by Brewzologist »

Well, puck erosion is normal so you'd expect pressure to decline during a shot, and for me this decline often accelerates toward the end of the shot. But it sounds like this is something more abrupt, which I haven't experienced with my F58. A few thoughts on potential causes, and please pardon if I am stating the obvious a bit:

1) Are you maintaining consistent pressure on the lever throughout the pull? If not you could experience pressure drop from the inlet gasket at the top of the plunger if the seal breaks.
2) Have you lubricated the gaskets with a food safe lube? Mine will stick on the walls of the group head after cleaning unless I apply lube.
3) Are any parts binding during the shot? I have an older Flair and in the photo below (exaggerated for effect) the black plastic guide will hit the top of the group head if not fully clipped in.
4) Is your plunger oriented so the tab holes are front to back? (see image below)




ab
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#4: Post by ab »

For me it's none on the things you mentioned and seems almost exactly like the OP's issue.

Pressure is good and then about halfway in the pull, the abrupt situation occurs and there is somewhat of a "pop" in your arm. You have to push harder then and bring it back up to pressure.

I've found that if I fill the reservoir, pull up slowly then fill it a second time, it's less likely to occur, but then the puck is being exposed to water for a longer amount of time than I would prefer.

JonTheFisherman (original poster)
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#5: Post by JonTheFisherman (original poster) »

Brewzologist, thanks for the detailed answer. I lubricated the O-rings tonight and will test it in the morning. If the issue is still there, I will look into shortening that black guide thingy because I suspect it might be the main culprit - the pressure drop/perceived physical shift happens about the same time it enters the cylinder (and potentially gets pushed by the inner wall and shifts). I will follow up with more findings tomorrow :)

JonTheFisherman (original poster)
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#6: Post by JonTheFisherman (original poster) »

Here is a video I shot earlier that shows more or less what is happening (particularly at 0:57-0:58):
Here is Flair's answer:

Hi Vladimir,
The shift and click you've shown in your video is the result of the normal articulation of the linkage system that drives the piston on all 58s. If you watch closely during the shot, the stem will move through an inflection point in the normal action of the lever upon the hook and stem, where it changes from a forward tilt to a rearward tilt, and you will hear a slight click when this happens. The action on the plunger also causes it to cycle through a slight tilt in each direction. This is actually the reason for the smaller top o-ring on the plunger, which is what we refer to as a "dummy" o-ring, and which serves no sealing purpose at all, it is simply there to provide a bit smoother feel as the plunger goes through its articulation, and it tilts a bit in the chamber from that natural front to back motion of the hook to stem junction as the lever is depressed.

So, all this to say this is a part of the normal working cycle of the mechanism, and nothing to be concerned about. Please don't hesitate to reach out if you have any additional questions. Happ Brewing!


Any thoughts? That still doesn't explain the drop in pressure.

jpender
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#7: Post by jpender »

I can see how that might result in a pressure drop. It takes you some time to adjust to that sudden change in the mechanical orientation of the lever. It won't keep you from pulling a good shot but if it were my machine I'd be kind of disappointed. It sounds to me like they added the small o-ring as a kludge to patch a design flaw.

ab
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#8: Post by ab »

That's a disappointing response from Flair. Another reason why I'm interesting in the Meticulous.

This does seem like a design flaw. :/

jpender
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#9: Post by jpender »

Well it doesn't seem to happen to everybody so perhaps there is something you can do about it. Maybe cleaning and lubricating the little o-ring would help. Or if there is some roughness in the metal you might be able to polish the area that is getting stuck momentarily. No machine is perfect.

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Brewzologist
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#10: Post by Brewzologist »

Both my Pro2 and F58 articulate, and I don't consider that a design flaw per se. But, I've never experienced the abrupt shifting and click sound you are having with the F58 when you pull a shot. I wonder if your unit has some slight defect in workmanship where the parts don't slide smoothly as this articulation occurs? From watching the video my theory would be the abrupt shift allows the pressure on the plunger to lapse, causing a brief pressure leak or drop before rising again as you continue your pull. If I were in your situation I'd revisit this issue with Flair support noting the pressure drop which is also happening. I would hope on a brand-new F58 that Flair will make good.

EDIT: I pulled a shot with my F58 after watching your video. It does not have the abrupt shift of the plunger occur as the arm articulates mid-shot. My guess is there is something amiss between between the contact surfaces of the linkage arm and the plunger. You might check those and the screws/bolts holding them together.