Does a vibe pump fail suddenly?

#1: Post by **sunnyu** » March 20th, 2006, 10:10 am

Does a vibe pump fail suddenly, or does the performance gradually decline.

I have a CEME (47watt) vibe pump. disassembled and cleaned throughly.

outputs 2oz in 15 seconds (@PF)

March 20th, 2006, 6:03 pm

Dan, surely you can put me out of my misery!

#3: Post by HB » March 20th, 2006, 7:48 pm

Err-r, I actually don't know the mean time between failure rates (MTBF) of vibration pumps. Do they go quietly into the night or suffer death rattles for weeks before expiring? Not sure. I wonder if the flow rate without impediment would be within specification, i.e., if there's an obstruction upstream. Other than that, if you've had it completely disassembled and found no evidence of excessive wear, I'm stumped.

BTW, despite having read thousands of problems with espresso machines and closely following the accounts to their final resolution, personally, I've never had any repair issues other than ordinary maintenance. Good choices or dumb luck? Probably a little of both.

#4: Post by **s_m_k** » March 20th, 2006, 9:38 pm

Any chance the check valve is leaking? I don't know if this is incorporated in the pump or just downstream from it.

March 21st, 2006, 1:01 pm

So I take it that all the talk about measuring pump pressure and installing gauges is to do with initial setup and finding the optimal point. And once it's set it does not fluctuate or deteriorate.

#6: Post by HB » March 21st, 2006, 1:08 pm

Yes. I've read many accounts of pumps suddenly failing to work, but I don't recall stories of pumps slowly losing ummpf. Most don't attempt repairs, they just order a new one.

#7: Post by **cannonfodder** » March 21st, 2006, 2:07 pm

sunnyu wrote:So I take it that all the talk about measuring pump pressure and installing gauges is to do with initial setup and finding the optimal point. And once it's set it does not fluctuate or deteriorate.

I don't know about that. I personally have a one year old Isomac millennium that has lost about one bar of pressure over the past couple of months. I am not attributing that to a decline in the pump, but the OPV tension spring 'breaking in'. With a blind basket I was getting almost 10 bar. During extraction I was right on the money at 9 bar. Now I am getting 9 bar with a blind basket and just over 8.5 to 8 during the extraction. I need to crack the case and give the OPV a twist of the wrench.

When I get home today, I will put a measuring cup under the PF with no basket in it and measure/time the water flow for comparison.

When the heating element kicks on, the pressure drops about .5 bar, which is a problem with most all consumer machines. There is just not enough power in a 110v 15amp circuit to support both, but that is another thread.

March 21st, 2006, 3:49 pm

cannon,
Would be most interested to read the results. Thanks.

#9: Post by **another_jim** » March 21st, 2006, 5:26 pm

cannonfodder wrote:When the heating element kicks on, the pressure drops about .5 bar, which is a problem with most all consumer machines. There is just not enough power in a 110v 15amp circuit to support both, but that is another thread.

You can get relief in two ways:

1. Finding an outlet close to the circuit breaker panel (not always possible). If you are really incensed by this, run a 12 gauge extension cord to a close outlet.
2. Replacing the existing 18 (!) gauge power cord of the machine with a 12 gauge cord (the wiring on Italian machines is never changed compared to the 220 models -- a very bad practice, albeit within code, since they spec very fine wire gauges for "within panel" wiring). This fix got me from 1/2 bar down to about 1/6th bar change during heating cycles.

#10: Post by **s_m_k** » March 21st, 2006, 7:26 pm

cannonfodder wrote:When the heating element kicks on, the pressure drops about .5 bar, which is a problem with most all consumer machines. There is just not enough power in a 110v 15amp circuit to support both, but that is another thread.

I don't doubt that you've seen this, but it doesn't make sense to me. I thought that pumps typically operate well above the required pressure (15 bar or so) and the OPV regulated down to the "working" pressure.

Is this a false assumption? After all, I am a newbie.