Post By rawill
Post By TampIt
EM7000 steam issues
My in-laws have an EM7000, bought second hand (looked new) and they've had it for a year. Machine is probably 2 years old.
The steam fails on it, the pump sounds fine but the steam is really weak.
I have replaced the steam pump and first test after installation the steam came on full strength again but ever since then the steam has been weak.
The strength of the steam varies a lot but never full strength like it used to be.
I am guessing the other possible causes are thermoblock or main control board?
They've bought a replacement now which is actually the older model EM6910 but brand new just so that they have a warranty as they are sick of these sorts of faults and just want a working machine without a huge price tag.
I am looking at either trying to repair it or take it to someone to get repaired, or maybe just sell as is.
Originally Posted by applor
Having owned both two 6910s and a 7000 (all fine) and seen a pile of friend's 6910s with blocked steam wands, I am a little surprised someone could block a 7000 (at least using properly filtered water).
In the west, most users block the 6910 steam wand with milk (no one in their right mind uses the corrosive "reputed to be tap water" here). In the east, the use of poor water seems to block up the thermoblock instead. Pump failures are rare, and have a 5 year warranty anyway (if I recall correctly, the 6910 certainly does).
The 7000 has two cleaning cycles - if you use white vinegar in the longer "Descaling Cycle for both the Coffee and Steam Thermoblocks" it should clear any partially blocked thermoblock or wand. The only issue I had with that in a friend's 7000 is that I ended up doing another three complete descaling cycles using rainwater before the steam system stopped tasting of vinegar... Easy test - just purge some steam into a large container and smell it before you destroy some perfectly good milk.
Use of suitable filtered / rain water is essential in any espresso machine for long term health.
PS: P23 of the online manual has the descaling cycle.
How strong a solution of white vinegar to you use for for descaling.
Want to make sure my EM6910 stays good, and use it in the used 5600 I bought recently for a song, NZ$16.50.
Only bought it for the P/F so I could make it naked.
Originally Posted by rawill
I didn't really think about it much until this post, so I exhumed my SB 6910 & 7000 manuals to see what they said. I then decided to make this post (epistle?) more general. If you are asking, probably a few other CS'r's are also wondering.
Firstly, "taste test" the water from either the group or steam wand. If it is tainted, clearly you need to do something to fix it. Think about that tainted taste in your cuppa... you know, the one you just drank while trying and failing to dial the taste in!
Secondly, how often do you need to descale a machine? Simple: When the taste test above is a fail.
Personally, I use filtered rainwater in all my machines and luckily I was taught how to froth milk correctly so I have never had to descale any of them*. Use poor quality water and the required descaling time can be as short as three months (e.g. several cafes & friends machines until they learnt to use decent water).
My method (as taught in the late '70's):
Use about 3 tablespoons (the imperial one) of white vinegar per litre (obviously the metric one) for groupheads and about half that strength for steam wands / steaming systems (boilers or thermoblocks). Using brown vinegar also worked in a cleaning sense, however I found it took a lot longer to get rid of the vinegar taste. YMMV - FWIW, I really, really hate foreign tastes in my cuppa.
Steam (milk) system:
Some early twin boiler machines do not appreciate high pressure & temperature "vinegar steam", so I just run short bursts of vinegar solution through the steam wand. Probably twenty seconds or so (I get the timing when I first smell the vinegar on the first steaming cycle), then I let the steam system cool off for a minute or two. That also lets the vinegar work into any remaining crud in the steaming system. Without counting, I probably use 6 or so cycles if the taint is slight, maybe 20 cycles if it is really yukky. A couple of really bad ones I even had to repeat the whole 20 cycle thing again. After that, I usually have to put at least a litre of clean water (in approx one minute pulses, one minute to cool) through the steam wand to get rid of the "vinegar taste" - luckily it is quite different from the "tainted taste", even if it does truly horrible things to the flavour of frothed milk.
Group head (coffee) system:
Depending upon the severity of the tainted taste (I usually head it off early if I am involved in the maintenance of the machine) I would put at least 2 litres through the group. The worst machine ever (plain water from the group would fill a large room with a noxious stink after a couple of single shots) I think I used about 8 litres in 1 litre cycles with 15 minutes to let the solution soak into the plumbing. I actually kept it up until I could only smell vinegar (i.e. no taint) and then gave it two more litres "to be sure". Just like the steam system, it needs a litre or two to get rid of the taste of the vinegar. At least it is a lot faster to put water through the group...
Hot water tap: A lot of machines have a hot water tap, some people even use them. FWIW, I don't use them as a rule: In a really busy environment it helps to stuff up boiler pressure & temps in early commercial machines and using a kettle is easier and faster for large volumes of water for things like tea. Later, oversized thermoblock machines (i.e. the 6910 & 7000) tend to have smallish tanks, so filling them too often becomes a PITA. Once again, a temp controlled kettle is a better option for me. Modern machines are far less finicky about that, so I am probably "old school" in this issue.
I treat the hot water with the same solution same as the group. I just let the water flow until I can smell the vinegar and turn it off. I then let it sit for about 15 minutes and repeat a few times (usually the same number of times as the group, but that is probably just habit).
I have never had a failure using that on dozens of different machines over the years, so it is probably pretty close to middle ground in terms of the mythical "average coffee machine".
SB specific stuff:
Interestingly, my SB 7000 manual (P23, "Descaling Cycle for both the Coffee and Steam Thermoblocks") says to use about 2 tablespoons per litre (actually 6 tablespoons per 3 litre: the 7000 tank size). Strangely, the 7000 manual does not mention vinegar in their "coffee thermoblock cleaning cycle" (P22) - a really odd omission unless you sell cleaning tablets... Anyway, their recommended concentration is about in the middle compared to the way I was taught. Considering it has a single tank, I suppose the concentration makes sense.
I just checked my 6910 user manual: Descaling (P32) has the same vinegar solution concentration for the group with a note - "Important: Do not run descaling solution through the steam wand,"!!! No mention of vinegar except by indirect implication. "Cleaning the group head" only (P30) has the same instructions as the 7000 (i.e. without mentioning vinegar at all). Seems like marketing inferior tablets to me...
Mind you, if a 6910's wand is fully blocked with milk (the West Oz most common fault) then I just take the machine apart, pull the wand off and drop it in toluene overnight... in a safe environment for using such a toxic chemical - no kids or pets near in any case! Note: Even an ultrasound bath will not shift 6910 "total milk blockages" (we tried all the usual culprits first, followed by a number of arcane & specialised methods: nothing else worked). Luckily toluene doesn't eat the 6910 chrome, a couple of old Italian commercial machines were not so lucky.
A few stray thoughts:
Please note (you and any other CS'r's) that the taste of vinegar seems to hang around forever in a steam wand, especially if you are using rainwater. That may well be why I was originally taught to use a lower concentration for a steaming system. Also, most of the earlier specialised cleaning solutions seem to only work effectively on the group, not the steam system. A couple of well known brands of cleaning solutions actually damaged the inside of the steam wand (actually bored it out and screwed the steam pressures up) of some commercial machines I had to repair - an expensive "wand replacement" fix. That is why I haven't used any of the "new wave" of special cleaners for years if at all. Clearly, YMMV on that one!
Enjoy your cuppa
* My original La Pav 2 group (plumbed in) went for twenty+ years without more than the odd boiler "separate, clean & flush" to remove the "old traditional boiler fish oil taste" every 6 years or so. Mind you, every six months or so I emptied the boiler out, pulled all the other accessible parts out and let everything dry out overnight whilst I cleaned all of the non-routine maintenance parts. In hindsight, I probably got slack and caused the fish oil thing by carelessness.
Thanks TampIt for your detailed responses. I will have to try and de-scale the steam wand and thermoblock then to see if it fixes the issue. I am about to leave for holidays so won't get to it for a couple months though.
Well after 10 months in storage, I have retrieved the machine from my in-laws to have a try at fixing the steam.
So I turn it on and the steam works great, really strong and powerful.
I decide it should get a clean and certainly needed it after removing the shower screen. Just filled with old coffee gunk it was disgusting.
I pull the screen and seal out and clean everything.
I proceed to do a full descale for main pump/steam pump and that all goes well. Pretty much nothing comes out from the descale and water flows freely through the steam wand.
So that is good news.
I do a full cycle again just with clean water to thoroughly flush out the descale.
I then go to test it again and I am now back to square 1. Steam is pitifully weak, basically nothing comes out.
I know its not the pump (new) and I know the thermoblock/wand are clear. What does that leave? I am guessing a bad electrical connection. Any other ideas?
edit: it seems after reading this thread:
That the relay for the steam thermoblock may be playing up.
I will try replacing that next.
Replaced the relay, still giving weak steam.
After replacing the relay though I payed closer attention to the machine during the weak steam - I can hear a relay frequently clicking.
I believe this is the steam pump frequently cutting in and out. Why it is cutting in and out, I do not know - any experts who can point me in the right direction?
A failed relay won't cause weak steam, it will cause no steam and just water.
Weak steam is usually either:
a) Scaled or otherwise blocked steam thermoblock
b) Leaking relief valve on the steam pump
Remove the drip tray grille and activate the steam, can you see a steady drip of water entering the drip tray from the top left corner? If so, the relief valve on the pump is open.
This can be because the relief valve is damaged (new pump so probably not the case) or it is open due to a blockage in front of the pump (thermoblock, pipes) causing enough back pressure on the pump to open the valve.
Your descaling may have moved a chunk of scale around the thermoblock where it's now got stuck again. You can check to see if there is a blockage by removing the tubes connected to the thermoblock (machine off and cooled all the way down) and by blowing through the thermoblock. There should be very little resistance.
You can also remove the other end of each tube and blow through them to see if there is perhaps a blockage there.
Also open up the steam tap and blow through the pipe that was attached to the thermoblock and see if a steady stream of air is expelled through the steam tip. Occasionally the teflon pipe inside the steam wand can become blocked or break down which will cause a poor steam scenario. This however is uncommon.
Well I accessed the steam thermoblock this morning and can barely blow anything at all. It makes a faint gurgling sound.
So it seems the thermoblock is blocked and needs to be cleared. What is the best way to thoroughly flush it out?
edit: reading through other threads I have decided to pour descale solution into the block and let it soak for 30 minutes. Hopefully this does the trick.
edit2: the soak did nothing and nor has syringing descale through it for 30 minutes. I get a small dribble of water out the other end.
Last edited by applor; 11th July 2016 at 11:24 AM.
Hi, I have a similar issue as above. I have an EM7000 but the steam is weaker than it used to be. I have descaled the machine and Thermoblock with a diluted white vinegar solution, but the steam is still weak. So it is not from scale. I have followed the above instructions and checked the relief valve. I think this is the issue as it is dripping water into the tray when the steam wand is on.
Now that I believe the issue is in the relief valve, how do I go about fixing it? Do I need to do more trouble shooting to find the root cause or can I change over the faulty part ie pump, or O-ring etc. Any help would be great.