Inconsistent brew pressure
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- Posts: 45
- Joined: 13 years ago
Over the past week my La Spaz V2 Mini has developed a strange problem while brewing. After starting the shot, the pressure gauge initially reads ~10 bars (a little high, I know) and the vibe pump sounds as it always does. However, about halfway through, the brew pressure begins to oscillate between 5-6 bars and 10 bars, with the vibe pump getting quieter and louder as the pressure drops and rises.
I've tried pulling a blank shot with the backflush disk in and I get a pretty stable 9 bars; however, the pump sound is quieter than usual when I do so. I've also changed my beans and tightened up the grind a bit to no effect.
Any ideas how I can better diagnose and fix the issue?
For full disclosure, for the prior couple weeks, I was pulling shots at 12 bars (I was having a bitch of a time adjusting the brew pressure)...hopefully this didn't cause any long-term damage? I couldn't have pulled more than 30 shots at that pressure.
I've tried pulling a blank shot with the backflush disk in and I get a pretty stable 9 bars; however, the pump sound is quieter than usual when I do so. I've also changed my beans and tightened up the grind a bit to no effect.
Any ideas how I can better diagnose and fix the issue?
For full disclosure, for the prior couple weeks, I was pulling shots at 12 bars (I was having a bitch of a time adjusting the brew pressure)...hopefully this didn't cause any long-term damage? I couldn't have pulled more than 30 shots at that pressure.
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Sounds like a weak/dying vibe pump to me. I've had a few of them, so I'm pretty familiar with it. If your pump gets quiet during a backflush, that's probably because the flow is dropping to zero, another sign of a weak pump. Look for the tubing with the exhaust from your expansion valve, which should feed either back into your reservoir or into your drip tray. When operating normally you should see water flowing out the exhaust during a blank shot, otherwise the pump is probably failing. Its worth your while to disassemble and clean your expansion valve just in case its the issue. Also make sure you don't have any pinches or kinks in any of your tubing.
Sometimes you can eke a little more life out of it by adjusting the expansion valve to turn the max pressure down further.
On the up side, on my machine at least replacing a pump is fairly quick and easy. Good luck.
Sometimes you can eke a little more life out of it by adjusting the expansion valve to turn the max pressure down further.
On the up side, on my machine at least replacing a pump is fairly quick and easy. Good luck.
- cannonfodder
- Team HB
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You could also have a power problem. Does the drop/rise in pressure happen to coincide with the heater cycling?
Dave Stephens
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- Posts: 45
- Joined: 13 years ago
Thanks. Yes, it seems as if there is very little water flowing out the exhaust when I pull blank shots, compared to what was typically coming out when I used to backflush.Nate42 wrote:Sounds like a weak/dying vibe pump to me. I've had a few of them, so I'm pretty familiar with it. If your pump gets quiet during a backflush, that's probably because the flow is dropping to zero, another sign of a weak pump. Look for the tubing with the exhaust from your expansion valve, which should feed either back into your reservoir or into your drip tray. When operating normally you should see water flowing out the exhaust during a blank shot, otherwise the pump is probably failing. Its worth your while to disassemble and clean your expansion valve just in case its the issue. Also make sure you don't have any pinches or kinks in any of your tubing.
Sometimes you can eke a little more life out of it by adjusting the expansion valve to turn the max pressure down further.
On the up side, on my machine at least replacing a pump is fairly quick and easy. Good luck.
I've owned the machine for 2 years, and it spent all but 8 months of that time in storage. I'm hoping it's not a dying pump and simply loosening the valve will help.
Is it possible I've messed it up by pulling 30-50 shots at 12.5 bars? I don't see how that could cause pump issues, though, but maybe that's wishful thinking.
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- Posts: 2892
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Have you checked the tank and the tubing from the tank to the pump?
There could Be a blockage In This part Of the machine. If you look closely In the water tank you Can see the part with the chrome, unfortunately the chrome is Of a very bad quality and should Be removed so it won't result In a blockage in the tank outlet. But it's quite ease to clean and remove any blockage In This part Of the machine, you should also check if the tube In the water tank is collapsing and the water tank filter could also Be causing This problem, try to remove bouth and see if that solves it.
If not try cleaning the pump and the OPV.
The pump the mini uses have a very good track record, so you would Be one Of the very unlucky few, if it turns out to Be a bad pump.
Some Of the parts In the brew group could Be damaged by such a pressure, so it's defiantly not a good thing that you have run it for so long.
There could Be a blockage In This part Of the machine. If you look closely In the water tank you Can see the part with the chrome, unfortunately the chrome is Of a very bad quality and should Be removed so it won't result In a blockage in the tank outlet. But it's quite ease to clean and remove any blockage In This part Of the machine, you should also check if the tube In the water tank is collapsing and the water tank filter could also Be causing This problem, try to remove bouth and see if that solves it.
If not try cleaning the pump and the OPV.
The pump the mini uses have a very good track record, so you would Be one Of the very unlucky few, if it turns out to Be a bad pump.
Some Of the parts In the brew group could Be damaged by such a pressure, so it's defiantly not a good thing that you have run it for so long.
- Spitz.me
- Posts: 1955
- Joined: 14 years ago
It's a dying pump. Save yourself the time and frustration and just go get a new vibe pump. It's a lot easier. If the pump is going quiet, it's finished. I know, that's happened 2 times to me and each time when I replaced it I didn't experience the same problem because the pump was failing.
Go look up several threads on vibe pumps going quiet. Aside from the one or two that attempted to open up the pump and do some gymnastics to 'figure out the problem' to no avail, it was mostly replacing the pump that actually worked.
I highly doubt that having the OPV set at 12.5 bar did anything to the vibe pump considering it is capable of more. Most, if not all cheaper, junk machines with vibe pumps come set at 15 bar AND THEY MARKET IT AS GREAT.
Go look up several threads on vibe pumps going quiet. Aside from the one or two that attempted to open up the pump and do some gymnastics to 'figure out the problem' to no avail, it was mostly replacing the pump that actually worked.
I highly doubt that having the OPV set at 12.5 bar did anything to the vibe pump considering it is capable of more. Most, if not all cheaper, junk machines with vibe pumps come set at 15 bar AND THEY MARKET IT AS GREAT.
LMWDP #670
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Running at 12.5 bar in itself probably doesnt do any damage, they're rated for more than that. However, they would also have pretty low flow at pressures that high. So if you were seeing pressure that high during an actual shot, you must have been pulling long, slow shots. Its possible you were over working the pump simply by letting it run too long. Or it may have been completely unrelated, I have had pumps fail in 8 months despite taking great care to never overwork them.
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- Posts: 45
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Good point. I was pulling long, slow shots, probably in the 30-40 seconds range. I thought I was having grinder/coffee issues so I kept tweaking, which is why I kept pulling them at that pressure. But again, we're talking no more than 50 shots...I wouldn't consider that very heavy use to cause damage.
Thanks, I will call Chris Coffee when I have time and get their thoughts, and also get a new pump.
Thanks, I will call Chris Coffee when I have time and get their thoughts, and also get a new pump.
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- Posts: 1211
- Joined: 11 years ago
That doesn't sound too awful. A good rule of thumb is to try to keep it not too much longer than 30 seconds, and make sure its off for at least as long as it was on.
Mine is rated for 1 min on / 1.5 minute off. Others are rated for 1 min on / 1 min off. Those ratings are for 25C water though, and since water in your tank inside your hot machine will almost certainly be hotter than that, you have to take that "1 minute on" rating with a grain of salt.
Mine is rated for 1 min on / 1.5 minute off. Others are rated for 1 min on / 1 min off. Those ratings are for 25C water though, and since water in your tank inside your hot machine will almost certainly be hotter than that, you have to take that "1 minute on" rating with a grain of salt.
- Spitz.me
- Posts: 1955
- Joined: 14 years ago
I'm pretty convinced that consistently pulling tight shots in the 40 and above range drastically reduces the vibe pumps life. Now, I don't mean, it's a shot that you cut at 40 or more with good flow. I mean, you're just trying to eek out a ristretto up in that range. My experience with vibe pumps is that I hate them.
YES, I like playing with ristretto levels and I may have been stupid several handfuls of times...
YES, I like playing with ristretto levels and I may have been stupid several handfuls of times...
LMWDP #670