Pulling shots and steaming simultaneously on heat exchanger espresso machine

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Aintmissb

#1: Post by Aintmissb »

On my 4 year old ECM technika heat exchanger machine I occasionally pull a shot and steam milk simultaneously, as I have seen friends do and as I believe you should be able to. There is a distinct loss of pressure, from about 1.4 bars to about 1 when I do this, and as a result, the steaming isn't very successful. Do other owners with heat exchangers do this?

John49

#2: Post by John49 »

Once you've reached 1.4 bar the steam is flowing at the maximum velocity through the orifice. Lower pressures will reduce the velocity and the amount of shear force available.

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homeburrero
Team HB

#3: Post by homeburrero »

Normally the pressure that a steam boiler settles into when the element is full on and the steam wand valve open is determined by two factors: the power (wattage) of the element and the size and number of orifices in the wand tip. The size of the boiler makes a difference in how quickly the initial pressure drops but does not affect the pressure that you eventually end up with - that's just a balance between how fast the element generates new steam and how fast the steam wand orifice(s) let that steam escape.

Here's a nice discussion from the late Dr Pavlis about that: Optimal steam tips

When you are brewing and steaming at the same time on an HX, then you would logically expect it to settle in at a somewhat lower pressure than if you were not brewing, because the cooler HX is absorbing some of that energy generated by the element, leaving less of it available to generate steam.
Pat
nínádiishʼnahgo gohwééh náshdlį́į́h

prust
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#4: Post by prust »

The way an HX works you should be able to steam and pull shots at the same time with minimal impact of the shot. You have a boiler full of super heated water and steam. When you steam, you open a valve that draws the steam off the top of the boiler. When you pull a shot, there is a coil inside the boiler filled with water and that water moves through the coil into the group head. The water sitting in the coil is super heated if the machine has been resting for a while. That is why HX machines need a cooling flush before pulling a shot. You are moving 30-60 ml of water through a much larger (1000-6000 ml) boiler. The water flowing through the coil is heated as it travels and the thermal mass of the group head helps keep it at a stable temperature. When pulling a shot while steaming, the boiler only has a tiny amount of heat to recover but the heater is also on when steaming, so any impact on steaming in minimal.

kurisuni

#5: Post by kurisuni »

I have the profitec pro 500 and usually pull and steam separately. when i've trying doing both simultaneously, it's taken longer to steam (like, twice as long), presumably because of a decrease in pressure.

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mrgnomer

#6: Post by mrgnomer »

If the vacuum relief valve is closing properly and your boiler is coming to full pressure it might be your boiler water level. Too low or too high water level can rob you of steam pressure. You could draw hot water out of the water wand to see how the probe responds for the fill. You could pull the probe connection to overfill a bit and see how that effects your steam pressure. You can pull your water level probe to check it for hard water build up and clean it if there is.
Kirk
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professionals do it for the pay, amateurs do it for the love

CSME9

#7: Post by CSME9 »

I use an HX @1.2 bar, pull shots and steam at the same time with no issues .

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homeburrero
Team HB

#8: Post by homeburrero »

I run at a lower pressure (0.9 - 1.1 barg) and also use a very slow steam tip (Isomac new, with two 0.9 mm holes). I normally steam after pulling a shot, but I can do simultaneous with no problem. I just did an informal experiment on my machine (Giotto Evo V2) with 1 full minute of steaming. If I start steaming when the pressure is rising past 1 bar, and don't pull a shot, it will gradually rise to 1.1 bar in 60 seconds. (I.e., my heater more than keeps up with my steam nozzle.) If I pull a 35 second simulated shot in the middle of that minute of steaming, my pressure will drop down to around 0.95 bar at the end of the shot, then slowly come back up after I stop the shot. Not enough to make a noticeable difference in my steaming performance.
Pat
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Nsorens

#9: Post by Nsorens »

My Lelit Mara X will steam milk and pull shots simultaneously even though it is set to favor brewing temps. Steaming is just a little slower but still works fine.

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cafeIKE
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#10: Post by cafeIKE »

Ever descaled?
Scale buildup can affect the water level and heating element efficiency.

What is the tip like?