Author Topic: Classic, solenoid or pump issue - help needed!  (Read 4450 times)

Offline D4F

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Re: Classic, solenoid or pump issue - help needed!
« Reply #15 on: December 11, 2017, 01:02:38 PM »
Let the machine warm, but not critical as to 15 minutes.  The test is at high flow and the will cool the pump and machine a bit - cool water at faster than brew flow.  Also, since you are catching flow from the steam wand and the boiler in the same run, note the volume from each.

This test should be next.  It takes less time to run the test than to think up thread posts.  At this point, we need to find out if pump, flow, OPV and solenoid are the problem or can be eliminated.

You initial title and posts noted that you were quite sure that it was pump or solenoid.  Before chasing every thought, lets solve this one.

And yes, pump noise varies with the elements running and or with pressure building such as with back flushing.

Offline DG Classic

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Re: Classic, solenoid or pump issue - help needed!
« Reply #16 on: December 12, 2017, 03:56:02 PM »
Hi,

I did the test today and even before that I figure out what can be the cause, after you gave me a few tips, I've connected that the temperature has something to do with it. In short, 20-25 min is not enough to warm the machine, like I did most of the time and it worked fine, but I didn't realize that colder room (kitchen) temperature would so much prolong the warming of the machine, and honestly I never read anywhere that the warming of the machine is important for keeping the pressure for brewing. I am maybe wrong, but it seems like it was said, that warming is important for higher stability of hot water during the shot which is necessary for better espresso...

So I never read some advice like: keep in mind that if the outer space of the room is colder you will have to extend time of warming of the machine, because the PRESSURE needs hot environment to work properly... and not only coffee.

To non-engineer like me it's easy to skip such details which are implied.
Maybe I'm wrong and maybe I've just missed that detail. It's all the same to me and for those like me who might not connect those things.

That's also the reason why I am writing this, if someone somewhere would search something regarding similar confusion, maybe this explanation to myself will help them, too.

Finally at the end, after I've heated the machine for 40 min, everything was different, like it was before. I measured 132 ml in 30 sec, I did the test couple of times and it showed the same result.

Thanks a lot D4F and JojoS,

This conversation and tips helped me and led to a result, now I only have to wait for my Sumatra Mandheling to arrive from England :)

« Last Edit: December 12, 2017, 03:59:15 PM by DG Classic »

Offline D4F

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Re: Classic, solenoid or pump issue - help needed!
« Reply #17 on: December 12, 2017, 07:38:44 PM »
I don't see where you measured the total flow out of steam wand and group, with steam switch off and no PF in.  That should be 600+ ml and a bit over half from the steam wand.  If all is well, then you may not need to bother, though that is a quick test.

I don't think that the warm up stabilization time is significantly affected by room temperature in a heated insulated house.  Warm up time for me is still about 15 minutes summer or winter.  In-house temperature is not that different, and my boiler temperature at turn on is similar. I can see boiler temperature on the PID controller as soon as I turn on the machine.  I don't see how boiler brew pressure is affected by room temperature, unless a defective pump that is affected by temperature in the machine case.  The ones that I read about have pump failing when hot, so less pressure.

Offline DG Classic

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Re: Classic, solenoid or pump issue - help needed!
« Reply #18 on: December 13, 2017, 04:39:24 PM »
I am a bit confused about the test you are referring, in the previous post you've mentioned the test with two cups instead Gaggia tank - one cup filled with water and the other one empty, switching the brew button and timing how many ml should come in 30 sec, you wrote : If you have a healthy pump, then it will flow about 260 ml/minute at 9 bar, right? That's the test I was writing about, and that test was OK.

So, you mentioned letting water through the group and steam as well, but I didn't know if you suggested to do both or one of them.

About warming of the machine, if you warm the machine in a room where the temperature is 20°C and if you warm the machine in room a where it's 25°C, you say that doesn't change the time of warming up of the machine?

OK, after 15 min of warming up the machine I run the other test, that 600 ml test failed because I measured about 267 ml (not each, it was combined) - it doesn't matter that first test was all right?



 

Offline D4F

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Re: Classic, solenoid or pump issue - help needed!
« Reply #19 on: December 13, 2017, 07:09:59 PM »

What is the volume of water combined from the group and open steam wand in 30 seconds (steam switch off)?

Remove the tank and replace it with "two tanks," a full glass of water and an empty glass for OPV return flow.  Use a blind PF or equivalent to block the group and measure flow back through the OPV into the empty glass for 30 second and note that flow.  You will then have pump flow with minimal or no resistance and pump flow at your OPV setting.  Have you ever changed the OPV pressure?  Another helpful value would be pressure at the group with a gauge, but a good start without.

Sorry that I wasn't clear.  Test 1 is with the tank in place.  Open the steam valve and then put a container under the steam wand and another under the group and run the brew switch (leave steam switch off).  This test measures flow against almost no resistance and is one test of the pump. Note the flow from each, and combined flow.

The second test, already done, is pump against resistance and was ok.

Likely test 1 will be ok, but easy to measure.  If total flow is down, then it may suggest some problem in the outflow tract, 3 way through group.  Steam valve is not usually obstructed unless a major scale problem. 

Offline DG Classic

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Re: Classic, solenoid or pump issue - help needed!
« Reply #20 on: December 14, 2017, 04:32:07 PM »
Hi,

I did the test as you've suggested, warm the machine 20 min and run water through the group and steam wand, it was identical 275 ml, together 550 ml, which is less than it should be I guess, not much less but less anyway. Does it tell you anything?

I also did back-flush but later, so maybe I should try the test tomorrow, again. I did notice something, water doesn't flow evenly from those small holes (dispersion plate, without shower screen), instead of that it rather goes through the middle, mostly, and occasionally appears from two smalls holes, not all four. The most amount of water goes through the middle (screw hole)? I don't know if the water should go there at all? This wasn't the case before, at least not a month ago when I removed the dispersion plate to clean it, then it flew evenly through four small holes.

I did remove it ( dispersion plate) today again to see if it's dirty, but it was completely clean. It was after I've done all, so I will see if there is any change in water distribution through shower screen.

What is the diameter of original screw for shower screen? I believe I have a ø 5 mm.


Thank you.

Offline JojoS

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Re: Classic, solenoid or pump issue - help needed!
« Reply #21 on: December 14, 2017, 08:14:03 PM »
Your pump is running fine. The water from the center of the dispersion disc is covered by the screw of the shower screen so don't fixate on that. If you are unhappy with the way the water is distributed out of the shower screen, you can loosen the screw a bit. Focus on improving your coffee prep techniques and just keep your machine clean like you currently do. Over and out!

Offline DG Classic

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Re: Classic, solenoid or pump issue - help needed!
« Reply #22 on: December 15, 2017, 11:32:58 AM »
OK, then even better  :)

I'll try to write  in short where I might be wrong.
Dosing... I follow recommendations of manufacturer and always tried to stick to the higher dose of the basket can take, because I like fuller body and strength of coffee ( I knew dosing won't help much for that but I hoped it would a bit). Considering how it's roasted and the nickle test I thought everything was fine. But obviously it wasn't. I'll try to follow my instinct and eyes as well in the future, and not blindly follow only what is recommended.

I tried with smaller doses in the last two days and it has already improved.
But there is always a lot to learn, the whole process is most fun.

Thank you a lot for assistance, until the next time :)

Have a good brewing!


 

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