Do you leave your espresso machine on all the time? - Page 2

[LeoZ]

the point of stress on the machine can be argued to either side, so i think it becomes irrelevant. if we were all so concerned, our shrines would be just that. but, at the end of the day, they serve a purpose, just like my stove does.

i voted yes, but thats partially true. if i know im going to be home working for a day, ill turn the machine on the night before. im convinced it stabilizes much better when its constantly on. steam performance seems better too.
i also tend to leave it on from thursday night through the weekend, for the friday before i go out shot, until sunday mid day.

ill be out of town from christmas till the 28th. im sad to leave my machine. thats pretty bad, huh. lol

[Compass Coffee]

15-20 minute "warm up" times on Prosumer machines? Me thinks not. Sure the boiler(s) will be up to temp, but the machine and brew path and group will not be close to up to temp, more like an hour minimum. You can of course manually force/speed warm up the brew path after boiler(s) up to temp with lots of flushing, wait for boiler temp to stabilize, flush some more, wait some more, flush some more...

While I don't leave my Bricoletta on 24/7, it's comes on by timer 4:30am (an hour and a half before projected first pulls of the morning) off 9:30pm (sometimes over ridden and turned off later).

[HB]

Sure the boiler(s) will be up to temp, but the machine and brew path and group will not be close to up to temp, more like an hour minimum.

Not to put too fine a point on it, but most prosumer HX machines will be temperature stabilized in 25-35 minutes, though there's certainly no great harm in allowing a full hour. For the purpose of guestimating the warm-up time for reviews, I lock in the thermofilter with the machine cold, turn it on, and then stop the clock when it reports the same reading for a few minutes in succession.

[Compass Coffee]

Not to put too fine a point on it , ok so a full hour may be a bit more than absolutely necessary. Was posting in reference to 15 and 20 minute warm up times posted for S1 & Alex respectively which I highly doubt would be temp stabilized. Room ambient will of course also affect warm up time. Since kitchen themostat turned downed to 55f over night takes longer to come up fully to stabilized temp than at 70f ambient so prefer to error on the side of being sure up to temp.

[jesawdy]

Well, according to this site, Sivia takes about 40-45 minutes to get the grouphead totally temp stable..... I usually wait 30 minutes or so and flush a bit.

[mogogear]

My tuppence.

My Conti Prestina has a 5 Liter boiler and is as temp stable as a rock. She is on all the time except when I go out of town. Does this wear on the machine? Yep, but she is close to regular commercial grade and if you have ever been in a shop, on is the mode for bigger machines. Could my p-stat give out? Yep, could the element ? Could the boiler? Yep I also have a really big source of hot water in my basement that clicks on and off and does so for years (10 or so) with very few needs - the hot water heater. I would assume they don't really concern most of us.
H-B referred to the two camps of thought above. One set of reasoning has been very elaborated on. The other is the akin to the the parallel "computer" argument. DO you leave you computer on all the time or not? Component failure and wear / vs startup failure.
There is hot water involved in our scenario which combined with a heating element makes for a more potent situation if failure occurs. I subscribe that merely some machines are not designed to be left on, some are. Owners of the latter at least have a choice. Prudence is always a good path if there is any doubt in the neighborhood. God p-stat, over-temp switches and fuses are all part of a good system to have in place.

Happy Holidays

[Psyd]

Interesting discussion topic.......
Firstly, I don't like leaving any electrical device in the on position 24/7 unless it's got a very sophisticated hibernation mode.

So, Al, electrically heated hot water; gas; or 'hot water on demand' for the shower and the sinks in your house?

I don't like the idea of hot reservoir water and a slimy tank. Blech. I say use a timer to turn it on and off as needed.

'Slimy' hot water in the boiler all night? I'd ask you what you rinse your dishes in, and what you shower in. Your morning shower has been in a tank all night, staying hot, and I'll bet a dollar to a donut that that tank is far 'slimier' than any espresso machine boiler in your house...

The truth is, do what the manufacturer recommends. From CMA's website (the manufacturer of my Astoria espresso machine):
"Switching off an espresso coffee machine (overnight) may save energy but what are the consequences, if any?
According to the general safety regulations, all electrical appliances should be switched off if they are not used for some time. CMA coffee machines are designed to be operational 24 hours a day, and are equipped with a pressure control thermostat & with a specific valve to grant their safety. As to the electricity saving, when a machine remains switched off for 10 hours, the energy saved is 6/7%. On the other hand, when the machine is switched on again, it needs about one hour to heat up & be in the proper operating conditions for brewing a quality coffee product. During this length of time the energy consumption is at its maximum levels and a large percentage of the energy saved by switching it off at night is lost. In addition, the machines gaskets are affected from the continuous temperature changes causing expansion and contraction and have a shorter life time."

For the less-than-prosumer models, I'd suggest on for coffee, off any other time. My two-group stays on 24/7 unless I am on the road for more than two or three days. The Silvia gets turned on by the first person awake, and it's about a half hour before I get my morning's ablutions out of the way, and if the PF is uncomfortably warm to the touch, she's ready. Silvia isn't one to be left to her own devices unattended.
Anything that auto-fills the boiler and is plumbed, I would guess would do just fine if left on. No worse than leaving the water heater on 24/7. Prolly a better boiler, and 'smarter' electrics, too!

Oh yeah, and I have notice that the electric bill has risen two dollars and seventy somethingeranother a month since I started leaving the big machine on instead of switching Silvia on every time I needed a shot. For less than a doppio at any decent shop I've got espresso and tea on demand. Making heat and maintaining heat are distinctly different jobs, and the former requires less energy, in the short run. It's the long run that makes things balance out.
And this is a 12 liter boiler we're talking about.

[HB]

No worse than leaving the water heater on 24/7.

To be accurate, water heaters aren't heated to over 250F either.

I never claimed espresso machines designed for continuous operation are unsafe if operated... well, continuously. The Astoria's explanation of potential savings defies my basic understanding of thermodynamics. Others more studied than I have debated this numerous times on CoffeeGeek and alt.coffee. Jim summed it up nicely and Bob offered my favorite analogy, the emptying buckets:

Actually, unless energy conservation is wrong, it should save money to turn it off for five minutes, more for 15 etc. The heater runs to keep the machine warm, making up the energy it loses by warming up the air around it. The total energy put in by the heater equals the energy lost to the air (that's the conservation law). Since the cooler the machine, the less heat it loses, any off time saves energy. That's all there's to it.

I used to work for a controls company when the energy crisis hit in the 70s, and I had a whole potted lecture, and a great run winning bar bets (and getting commissions on sold electric and gas meters) with plant engineers on this. The reason people never believed me was thermal storage ... The mass of the espresso machine (or whatever the boiler plants were heating) acts like a thermal storage, so until it "fills" up, the heater runs more. However, if you turn it off for a short period, that storage slows the cool down; which evens it out.

Is it a fair analogy to compare heat loss to a gallon bucket that leaks water at the rate of 1 qt per minute?

During 1 minute you have to pump in one quart of water to keep the bucket full. If you turn the pump off for one minute you will need to pump more than one quart per minute to make up for the lost water. In the end you will have to pump in the missing quart in addition to maintaining the quart per minute rate. But you will not pump any more than you would have, if the pump had run continuously.

[DaveC]

Really frightened of boring people....but just had to comment.

The comments on a 6%-7% energy saving if the machines are switched off at night instead of being left on, seem to be a case of commercial manufacturers maths, rather than any knowledge of science and thermodynamics. For starters the heat transfer from a hot body roughly does not increase proportionally with an increase in temperature. Simply put is something is twice as hot, loses heat more than twice as quickly (depending on materials and environment), i think it's Fourier's Law . Electric heating elements are 100% efficient (all the energy put into them goes to heating the water.

So a hot machine on all night will lose much more heat during 30 mins, than a machine being brought up to temperature, over a 30 minute period. Additionally, the machine is losing heat all the time it is not used.

Some logic in a theoretical example:

I have an amount of water....100 units, i need to keep at a temp of 128C for 24 hours.

In the first instance, I warm it up at a cost of 5 energy units for 30 minutes, keep it warm at a cost of lets say 0.5 energy unit per hours for a total of 24 hours. Total energy used 16.75 units.

In the second instance, I warm it up at a cost of 5 energy units for 30 minutes, switch the machine off for 23 hours, then switch it on again for 30 minutes to warm it up at a cost of 5 energy units . Total energy used 10 units.

Clearly it is more economical to leave a machine switched off if not being used for long periods. Translated to a real world example for an Izzo Alex.

24 hour period. Machine on for 12 hours and off for 12 hours or continuously on

Warm up phase identical for both machines at 30 minutes and 11 minutes of electricity (calculated as continuous element on time).

Machine on all the time, uses the heater for about 14 minutes each hour. So over night the machine uses an extra 2.8 hours of electricity during the 12 hour period.

Machine off at night saves 2.8 hours of electric, but consumes 11 minutes of electric to warm up before first use: So 168-11=157m saved

The saving of 157 minutes of electricity is significantly higher than the 6 or 7% claims by the manufacturer and is pretty much a halving of the electricity costs. In the scheme of things not much for an Alex, but a bit more for commercial machines, which is why many have a sleep mode or timed operation. The manufacturers don't have to pay for spares or repairs, or your electricity. In the long run all synthetics do not appreciate being hot for extended periods of time, in the same way as electronics. The thermal stress of heating and cooling a machine is also a VERY gradual process, unlikely to cause the damage they would like you to believe. And by god they don't want to make a commercial machine that lasts a lifetime

[Compass Coffee]

Machine on all the time, uses the heater for about 14 minutes each hour. So over night the machine uses an extra 2.8 hours of electricity during the 12 hour period.

Wow 14 min per hr, ~23.33% idle heater on duty cycle I suspect an error in data collection, that's terrible.

My Bricoletta only has a 5.55% idle heater duty cycle. I did gain ~35% improvement back when I insulated the boiler with ceramic blanket. But even before not near 23%, more like 7.5% idle duty cycle with uninsulated boiler. I did my timings with minimum 2 hour warm-up and/or 1 hour after last shot. (tested multiple times)

I've run the math and my locale costs ~$3 per month to run my Bric' 24/7. So any potential $ savings from turning on/off/on/off... would be non-existent or infinitesimal at best.