Bezzera Strega pump not engaging

A haven dedicated to manual espresso machine aficionados.
boy_lah
Posts: 27
Joined: 12 years ago

#1: Post by boy_lah »

hi HB! you guys saved my skin last year so I'm back hoping the wealth of knowledge here will come to the rescue again. :D

My Strega is 4.5 years old and gets constant use daily - 3 cups a day minimum. Basically, I am having problems engaging the pump and it's been progressively getting worst (increasingly more often) over 3-5 months. I would pull down the lever, and nothing...no rotary pump sound and no preinfusion. This usually happens when the machine is hot/after I've made a few cups/been idling for a while. It usually is fine from intial turn on from cold or if i let it cool completely (2-3 hours) and turn it on again.

Since it usually happens when hot I had suspected my microswitch may be broken or not be making contact as the heat is expanding some parts. So since then I've replaced the micro switch still the same issue.

And now I have my lever cap left off so i can manually press the micro switch...which i can hear the swtich click 'engage' but no pump. So it's not the switch I don't think so. And when the pump comes on, it works as expect so I'm thinking it's not a broken pump per se but maybe some electrical or contact issue due to heat?

When the group is empty, the pump is meant to auto-engage to refil the group, but that's not working either. I can sometimes hear the the machine attempting to auto-refil the group and similarly the pump doesn't come on. So again, kinda rules out the micro switch i think. This again, is usually when hot, AFTER my lever/microswitch turn on is not working. Otherwise, works fine first thing in the morning.

Also, I can confirm both lights on the front (green and yellow) are ON....which should rule something faulty with low water level in my tank.

Any suggestions/thoughts most welcomed!! Thanks HB!
LMWDP #369

User avatar
radudanutco
Posts: 147
Joined: 11 years ago

#2: Post by radudanutco »

boy_lah wrote: ... I would pull down the lever, and nothing...no rotary pump sound and no preinfusion.
...I've replaced the micro switch still the same issue.
... When the group is empty, the pump is meant to auto-engage to refil the group, but that's not working either.
...Also, I can confirm both lights on the front (green and yellow) are ON....which should rule something faulty with low water level in my tank.
there are quite a few issues here:
- Strega has no rotary pump! it is an Ulka E5 vibratory;
- the role of the autofill sensors is in keeping the boiler water at level! so, the pump is normally controlled by the brainbox for filling the boiler (POMPA line from the brainbox in the w diag below), not the group! also - of course - the pump is controlled by the microswitch when manually the lever is in its lowest position;
- the orange security lamp is off for several machine security problems, including the low water level in tank, but also low level water in boiler;
- I can hardly connect the problem you have with the pump not running, with another separate problem of the security circuitry, perhaps the sensing circuitry (could be shortcircuited to isolate the fault), or even the brain box;

better would be to check all these acording to machine wiring diagram included in the manual:


if it's true that you have the orange lamp on while the microswitch is closed and the pump is not functioning, that would limit the problem with the pump for the very circuit of the pump itself and the microswitch; and that is because this circuit is in parallel with the orange lamp circuit which is (even faulty) on;

boy_lah (original poster)
Posts: 27
Joined: 12 years ago

#3: Post by boy_lah (original poster) »

hi radudanutco, thanks for your reply!

Yes, my bad, vibration pump, not rotatry. Also yes, the pump autofils the boiler not group - got it.
As for my orange lights - it's NOT off. It's ON.

>>>I can hardly connect the problem you have with the pump not running, with another separate problem of the security circuitry, perhaps the sensing circuitry (could be shortcircuited to isolate the fault), or even the brain box;

This is my thinking as well. Some sensing circuitry is not working. I just need to figure out what and how i can trouble shoot. I am not that technical so I actually don't understand the diagram you highlighted. I'll see if i can show it to a friend if he understands it more.
LMWDP #369

jontyc
Posts: 124
Joined: 11 years ago

#4: Post by jontyc »

I once found the insulating shield between my GICAR and boiler (different Bezzera machine) had slipped out of place and was stopping the GICAR driving the pump. Similar setup in the Strega?

boy_lah (original poster)
Posts: 27
Joined: 12 years ago

#5: Post by boy_lah (original poster) replying to jontyc »

What is a GICAR? something slipped out or loose sounds about right. My pump is working but intermitent when warm which tells me probably a contact issue.
LMWDP #369

jontyc
Posts: 124
Joined: 11 years ago

#6: Post by jontyc »

Sorry, it's that black (overpriced) box maybe 4" x 2" x 1.5"- the brainbox as Radu mentioned above. After realizing that the Bezzera must have swapped orange to mean safety and green for power, I really can't see anything obvious if the microswitch is ok and light is on. It will be very easy to physically diagnose for someone electrically savvy if you can reproduce it, which it sounds like. I just wouldn't recommend it yourself as you are at 110V here.

IMAWriter
Posts: 3472
Joined: 19 years ago

#7: Post by IMAWriter »

jontyc wrote:Sorry, it's that black (overpriced) box maybe 4' x 2' x 1.5' - the brainbox as Radu mentioned above. After realizing that the Bezzera must have swapped orange to mean safety and green for power, I really can't see anything obvious if the microswitch is ok and light is on. It will be very easy to physically diagnose for someone electrically savvy if you can reproduce it, which it sounds like. I just wouldn't recommend it yourself as you are at 110V here.
Hopefully, you didn't mean 4FEET, by 2Feet, by 1.5Feet! :lol:
A reverse Spinal tap move!

I suspect the ...as you said, OVER PRICED Brain box. I'm lucky I'm OK, but I thought I saw somewhere they are something like $200 US!
To the OP, does your pump ever hum when you first start your machine, but not fully engage?

jontyc
Posts: 124
Joined: 11 years ago

#8: Post by jontyc »

Ha, it would justify the price better! Thanks for pointing it out. I'll edit.

User avatar
radudanutco
Posts: 147
Joined: 11 years ago

#9: Post by radudanutco »

it happens usually that when describing a problem with the machine, to include both relevant and irrelevant descriptors;
so, I didn't fully understood what is the situation with that orange lamp; as I said previously:

"if it's true that you have the orange lamp on while the microswitch is closed and the pump is not functioning, that would limit the problem with the pump for the very circuit of the pump itself and the microswitch; and that is because this circuit is in parallel with the orange lamp circuit..."

indeed, if this is the problem - orange lamp is on, and the pump does not function when it should, that could exclude the brainbox!
I mean the brainbox would be involved in the security circuitry for water level checking (tank and boiler), and this could be easily checked by emptying the tank and put it back; if the orange lamp is still on, there could be a grounding problem, and, of course, the "brainbox" itself;
if not, that is, the light is off in this case, hopefully there is no problem with the brainbox and with the orange lamp;

as jontyc put it: "It will be very easy to physically diagnose for someone electrically savvy if you can reproduce it, which it sounds like. I just wouldn't recommend it yourself as you are at 110V here."

boy_lah (original poster)
Posts: 27
Joined: 12 years ago

#10: Post by boy_lah (original poster) »

IMAWriter wrote:I suspect the ...as you said, OVER PRICED Brain box. I'm lucky I'm OK, but I thought I saw somewhere they are something like $200 US! To the OP, does your pump ever hum when you first start your machine, but not fully engage?
Yes. When the issue arises, either when the lever is down/microswitched engaged OR auto-refill boiler, i get this hum which signifies it's TRYING to do something but pump doesn't engage.

Is this the part people think is broken?? $250!!!!
http://www.1st-line.com/store/pc/Gicar- ... 4p4700.htm

Is it part no 12?
http://www.1st-line.com/store/pc/catalo ... ABLE07.jpg
LMWDP #369

Post Reply