Posted Sun May 4, 2003, 6:54pm Subject: E-61 Machines - Early Pump Burn-out?
As most people around here know, E-61 machines require flushing a significant amount of water through the grouphead, to bring the temperature down to around 200 F, before actually making a shot. Actually it's aboout 8 shots worth of water that need to get flushed before pulling a double ristretto shot.
Given the fact that us E-61 owners are pumping a significantly larger volume of water than other users, I was wondering if we owners can expect our pumps to need replacement every couple years or so. I guess most of us have Ulka vibratory pumps in our machines. Add to that regular backflushing and weekly flushing of the boiler (to eliminate mineral build-up in the boiler from excessive steaming).
QUESTIONS:
Does anybody know how reliable these Ulka pumps are for the volume of water they are required to pump?
What does it cost to replace a pump in a machine such as in an Isomac TEA/Millenium?
Can these new (experimental) mini-rotary pumps be retrofitted into an Isomac machine if the Ulka pump wares out?
Note: I'm double posting this question on alt.coffee as well.
Posted Fri May 9, 2003, 1:09pm Subject: Re: E-61 Machines - Early Pump Burn-out?
Bart, in answer to your 2nd question. Owen O'Neil commented on another thread a cost of I think $85 for the pump & ~20 minutes of time to replace it. One other concern I have about pump durability is keeping the machine on 24/7. I'm not sure if the constant heat exposure vs. the cycling up & down of temp. is a good or bad environment for the pump.
Noel Mano dell 'operatore> Macinadosatore> Miscela> Macchina espresso
Posted Fri May 9, 2003, 1:49pm Subject: Re: E-61 Machines - Early Pump Burn-out?
narc Said:
One other concern I have about pump durability is keeping the machine on 24/7. I'm not sure if the constant heat exposure vs. the cycling up & down of temp. is a good or bad environment for the pump.
I asked Chris from Chriscoffee about that one time, in the context of whether it is better to leave the machine on 24/7 or to cycle it on and off through the day.
He sort of implied that it might be less stressful on the machine if you leave it on 24/7, given the fact that the part would not be expanding and contracting all the time.
That said, I still cycle my machine on and off through the day cause I don't want to pay for the extra electricity. The TEA, left on 24/7 is roughly equal to a 100 watt bulb being left on all the time. No big deal...but probably a few dollars a month.
Posted Fri May 9, 2003, 3:48pm Subject: Does 24/7 operation reduce failure rate?
milnerb1 Said:
I asked Chris from Chriscoffee about that one time, in the context of whether it is better to leave the machine on 24/7 or to cycle it on and off through the day.
He sort of implied that it might be less stressful on the machine if you leave it on 24/7, given the fact that the part would not be expanding and contracting all the time.
That said, I still cycle my machine on and off through the day cause I don't want to pay for the extra electricity. The TEA, left on 24/7 is roughly equal to a 100 watt bulb being left on all the time. No big deal...but probably a few dollars a month.
I'm against 24/7 usage for similar reasons. I wondered what might be at the heart of these anecdotal stories of improved mean time between failure (MTBF) rates, and I figured that expansion/contraction of dissimilar materials could account for some of it. One way of eliminating this problem would be to program your PID to "bring it down" to room temperature over a period of a few hours. That would give all the components plenty of time to gently compensate.
Yeah, yeah, fat chance of that ever happening. ;-)
Anyway, here's my estimate of the cost of 24/7 operation, assuming a national average of $0.08 / KWh:
(16 extra hours / day) * 30 days * 0.1 KW * ($0.08 / KWh) = $3.84.
I have not measured, but the 100w assumption might be a little low, since the boilers are intentionally uninsulated to allow for passive heating of the cup shelf. And of course, commericial machines have even bigger boilers...
jim_schulman Senior Member Joined: 19 Dec 2001 Posts: 3,772 Location: Chicago Expertise: I live coffee
Posted Fri May 9, 2003, 6:09pm Subject: Re: Does 24/7 operation reduce failure rate?
dankehn Said:
I'm against 24/7 usage for similar reasons. I wondered what might be at the heart of these anecdotal stories of improved mean time between failure (MTBF) rates, and I figured that expansion/contraction of dissimilar materials could account for some of it. -- Dan
There's been quite a bit of back and forth on this. The expansion/contraction would affect long run repairs on the plumbed components, rather than the pump.
My concern is coffee quality; it takes my Tea about an hour to really warm up, shots before that are a bit more hit and miss. Commercial machines take about 3 to 4 hours to warm up, so any coffee store that switches them off doesn't care how their coffee tastes in the am.
Chris has changed his mind on this because of the electronics on some machines. He says he's seeing more frequent service on the brain boxes of machines that are turned off and on. He thinks the units may be sensitive to spikes that occur on switching. If he's right, it may be a good idea for people to get surge suppresors for people switching their machines. Jim Piccinich (sp) says much the same in an article.
I think the people who do service on our machines are in an excellent position to judge what can cause damage; so when two of them say the same thing, the surge suppressor idea is worth very serious consideration
Posted Fri May 9, 2003, 7:00pm Subject: Re: Does 24/7 operation reduce failure rate?
another_jim Said:
{edited} ...I think the people who do service on our machines are in an excellent position to judge what can cause damage; so when two of them say the same thing, the surge suppressor idea is worth very serious consideration.
I worked in quality control as a co-op and helped program for a statistical analysis department. By my nature, I distrust assertions without hard data, even from those in an excellent position to judge. It is too easy to draw "intuitive" correlations where none in fact exist. I'm reminded of the story of the server failure that occurred twice a day, once in the morning and once at the end of the day. The service engineer figured it was power spikes. You know, everyone cranking up their PCs at the same time in the morning, and flicking them off at the end of the day.
It was finally traced to a certain secretary passing by the server. She wore fancy stockings that generated lots of static electricity (wool?). It just happen that the shortest distance from the parking lot to her office was through the computer room. :-o
More seriously, it is surely wise to have spike protection for your whole house. Lots of power companies will gladly install one at the box, charging a small monthly fee. Simple appliances like Silvia won't care, but just about anything electronic does. Same goes for the phone and cable line (I know a colleague lost a motherboard because the onboard modem got fried during a lighting storm -- yes, need a surge protector there, too).
My concern is coffee quality; it takes my Tea about an hour to really warm up, shots before that are a bit more hit and miss. Commercial machines take about 3 to 4 hours to warm up, so any coffee store that switches them off doesn't care how their coffee tastes in the am.
Why does it take 3-4 hours for a commercial machine to warm up? That is, what isn't hot if you let its boiler come up to full temperature then drain a gallon or so through the PFs (twice if necessary)? Or is it a question of temperature stability?
jim_schulman Senior Member Joined: 19 Dec 2001 Posts: 3,772 Location: Chicago Expertise: I live coffee
Posted Fri May 9, 2003, 8:07pm Subject: Re: Does 24/7 operation reduce failure rate?
dankehn Said:
Why does it take 3-4 hours for a commercial machine to warm up? That is, what isn't hot if you let its boiler come up to full temperature then drain a gallon or so through the PFs (twice if necessary)? Or is it a question of temperature stability?
They have 8 liter boilers, but only about 2500 watt heaters (a Gaggia has 1300 watts for a 0.1 liter boiler). So it probably takes over an hour just for the boiler to get up to temp. However, well built espresso machines don't really do their best until they hit thermal equilibrium, and the entire machine, espcially the group, is up to temp. This is true even of a small machine like the Silvia, which tastes best after about an hour run time. For a big machine, that can take a long time. I forget who told me a commercial 3 grouper takes 4 hours, but it was someone who owned one.
Of course, it doesn't mean a thing in most cafes, with their 8 second, 4 ounce shots. But if one does it right, the bigger the machine, and the warmer absolutely everything on it is, the better the shot gets. Someday someone will figure out a way to do get quality without totally insane amounts of thermal mass; but it hasn't happened yet.
ljguitar Senior Member Joined: 28 Jan 2003 Posts: 2,450 Location: Cheyenne Expertise: I live coffee
Espresso: Expobar Pulsar Grinder: Mazzer Super Jolly, Solis Drip: Bunn Roaster: iRoast2
Posted Fri May 9, 2003, 11:13pm Subject: Re: Does 24/7 operation reduce failure rate?
another_jim Said:
-- well built espresso machines don't really do their best until they hit thermal equilibrium, and the entire machine, espcially the group, is up to temp. This is true even of a small machine like the Silvia, which tastes best after about an hour run time. -- But if one does it right, the bigger the machine, and the warmer absolutely everything on it is, the better the shot gets. -- Someday someone will figure out a way to do get quality without totally insane amounts of thermal mass; but it hasn't happened yet.
Thank you Jim for the detailed explanations... I am the kind of person who wants a lot of information so I understand a bigger picture. I think I understand your point...
You can heat a frying pan quickly, but that doesn't make it heat evenly which is important to cooking. That is why you turn it on and let it sit on the burner for a while before adding oil and food (to distribute heat).
Wow...never realized a large machine with an 8 liter boiler has only twice the power of my home machine. Now I see why it would need 3-4 hours to stabalize...or hit equilibrium as you called it.
Posted Sat May 10, 2003, 5:55am Subject: Re: E-61 Machines - Early Pump Burn-out?
Actually, E61 heat exchanger models seem to need more flushing then I do on my Zaffiro (dual purpose boiler model).I don't seem to have to run water to bring the temperature down to optimum.I use a timer that kicks the model on when I am awake and home. It turns off while at work,turns on 2 hours before I get up in the morn, off when I leave and on 2 hours before I get home from work. Been doing it from some time and haven't seen any problems (knock on chrome!).
Posted Sat May 10, 2003, 6:49am Subject: Re: E-61 Machines - Early Pump Burn-out?
coffeebeing Said:
Actually, E61 heat exchanger models seem to need more flushing then I do on my Zaffiro (dual purpose boiler model).I don't seem to have to run water to bring the temperature down to optimum.I use a timer that kicks the model on when I am awake and home. It turns off while at work,turns on 2 hours before I get up in the morn, off when I leave and on 2 hours before I get home from work. Been doing it from some time and haven't seen any problems (knock on chrome!).
Your right George. I kind of misspoke in my earlier post. I was referring to E61 machines with a HX. Since your Zaffiro is a single boiler machine, you probably don't need to run any water through in order to get the perfect brew temperature...lucky you. That's one of the advantages of the Zaffiro over all the HX models and most single boiler machines...you get an E61 machine with a fully dedicated brewing boiler.
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