Announcement

Collapse
No announcement yet.

EM6910 - deep clean?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • rawill
    replied
    An old thread, but a good thread.

    Leave a comment:


  • noidle22
    replied
    Originally posted by RichardP View Post
    There is conflicting info. In my opinion, NEVER try to descale the steam side by running the machine normally.

    The reason for the conflicting information is that Sunbeam simply says don't do it, but doesn't say why. That has lead to different people coming up with their own theories, but still having the desire to do the descale, which is not unreasonable, because the descale is actually required. It just should not be done by having the coffee machine running. Instead, use one other other methods that people talk about. Which one you use would depend on your own preferences and tecnical ability.

    First off, the reason you shouldn't: to understand that, take a step back and think about the reason you need to descale. When you have a water heater, the minerals in the water solidify around the hottest parts of the heater. This means we need to descale both sides. My guess is that the steam side needs to be descaled less often, since less water goes through it.

    So if we need to descale both sides, why is Sunbeam saying not to descale the steam side? To understand that, step back and think about the descaling process. The idea is to have water sitting in the heater system, warm but not hot, so that the descaling chemical (whatever it is) has time to react with the accumulated limescale. The warmth helps speed up the reaction. This works on the coffee side of the machine, but does not work on the steam side because in the steam thermoblock there is no water - the temperature is above boiling point to produce steam, so you cannot have water sitting inside the steam thermoblock while the machine is on. What's worse is that if you boil vinegar or any of the other descaling liquids, you produce solids which will end up becoming a problem in themselves.
    Another problem that happens if you try, is that there's a chance you will kill your steam pump in the process. Not a high chance, but it's not insignificant either. The steam pump in the EM6910 is of a type called a "metered pump". That brr-brr sound it produces is an oscillating rod inside. It moves back and forth, and in one direction it draws water in from the tank. In the other direction, it seals off the inlet and pushes the water out to the thermoblock. Inside it are parts that slide against each other. When the thermoblock produces steam, the pressure inside it increases, and the steam is happy to move in either direction. With plain water, that direction will always be towards the steam wand, because the steam pump's design allows flow only in one direction, so it's effectively blocking off one side of the thermoblock. Boil a vinegar solution, however, and you are producing solids that for short periods will block off the one side or the other before the pressure blows it out again. If you get a situation where the wand side of the thermoblock is blocked off, the steam will run backwards towards the steam pump. It won't get through the pump, in probably won't get close to the pump because there's a coiled piece of pipe in between them, but it may get close enough, for long enough, to heat up the water inside the pump, or in may cause the pump to overheat internally because the pressure makes it work harder. Either way - since the pump is not designed to handle higher temperatures - the rubber rings and seals in the metering mechanism will distort and start to bind against each other. When that happens, you still hear the pump working, but no water gets pumped through.
    Turn down the steam thermoblock temperature all the way and turn up the steam pump rate all the way. This will mean there's more water in the system when descaling as less will be converted to steam. It's effective in my experience.

    I've tried descaling steam thermoblocks warm, cold and hot and pumping solution through, letting it sit, cycling it frequently, cycling it less frequently, none of the methods have ever been as effective as turning the thermoblock temp down and the pump rate up and running the machine normally, letting it pump solution through for 30 second increments then allowing it to rest for 5 minutes or so with the machine off. Repeating this as many times as required until the solution coming out of the system returns to a normal colour.

    Regarding your claim of potential steam pump damage, the steam pump has a relief valve fitted at it's outlet to resolve this exact type of problem. When the steam knob is shut completely, the excess steam pressure in the system vents out of the relief valve to the tray. If often makes a strange squeaking sound.
    None of this steam gets to the internal parts of the steam pump. It does affect the rubber o-ring at the tip of the pump fitting though, over time it goes hard and leaks and is a primary cause of steam pump failures.

    Perhaps you were referring to the Ulka pumps used in the EM6900, they experienced failures due to not having a relief valve fitted. The workaround was to file a slot on the steam tap pin which allowed the excess steam to vent through the steam tip. Not a great fix but it was effective and really the only option they had other than a system redesign (enter the 6910).

    Leave a comment:


  • RichardP
    replied
    Originally posted by jimbojangles View Post
    Eep, ok. It's hard to know what's best - so much conflicting info on here and elsewhere about cleaning. Only use vinegar, never use vinegar etc etc.

    Perhaps I'll use the descaler through the group head and mild citric acid through the steam wand. I want to give it a nuclear clean before my first use, so perhaps I'll give it the one-of-everything method.
    There is conflicting info. In my opinion, NEVER try to descale the steam side by running the machine normally.

    The reason for the conflicting information is that Sunbeam simply says don't do it, but doesn't say why. That has lead to different people coming up with their own theories, but still having the desire to do the descale, which is not unreasonable, because the descale is actually required. It just should not be done by having the coffee machine running. Instead, use one other other methods that people talk about. Which one you use would depend on your own preferences and tecnical ability.

    First off, the reason you shouldn't: to understand that, take a step back and think about the reason you need to descale. When you have a water heater, the minerals in the water solidify around the hottest parts of the heater. This means we need to descale both sides. My guess is that the steam side needs to be descaled less often, since less water goes through it.

    So if we need to descale both sides, why is Sunbeam saying not to descale the steam side? To understand that, step back and think about the descaling process. The idea is to have water sitting in the heater system, warm but not hot, so that the descaling chemical (whatever it is) has time to react with the accumulated limescale. The warmth helps speed up the reaction. This works on the coffee side of the machine, but does not work on the steam side because in the steam thermoblock there is no water - the temperature is above boiling point to produce steam, so you cannot have water sitting inside the steam thermoblock while the machine is on. What's worse is that if you boil vinegar or any of the other descaling liquids, you produce solids which will end up becoming a problem in themselves.
    Another problem that happens if you try, is that there's a chance you will kill your steam pump in the process. Not a high chance, but it's not insignificant either. The steam pump in the EM6910 is of a type called a "metered pump". That brr-brr sound it produces is an oscillating rod inside. It moves back and forth, and in one direction it draws water in from the tank. In the other direction, it seals off the inlet and pushes the water out to the thermoblock. Inside it are parts that slide against each other. When the thermoblock produces steam, the pressure inside it increases, and the steam is happy to move in either direction. With plain water, that direction will always be towards the steam wand, because the steam pump's design allows flow only in one direction, so it's effectively blocking off one side of the thermoblock. Boil a vinegar solution, however, and you are producing solids that for short periods will block off the one side or the other before the pressure blows it out again. If you get a situation where the wand side of the thermoblock is blocked off, the steam will run backwards towards the steam pump. It won't get through the pump, in probably won't get close to the pump because there's a coiled piece of pipe in between them, but it may get close enough, for long enough, to heat up the water inside the pump, or in may cause the pump to overheat internally because the pressure makes it work harder. Either way - since the pump is not designed to handle higher temperatures - the rubber rings and seals in the metering mechanism will distort and start to bind against each other. When that happens, you still hear the pump working, but no water gets pumped through.

    This problem of not being able to descale the steam side has been solved on the EM7000 by a software change which allows the machine to run the steam thermoblock at a temperature below boiling point, so that no steam is produced during descaling. However, there were other changes made to the EM7000 which makes it an upgrade that is less than compelling.

    Leave a comment:


  • level3ninja
    replied
    What solution did you use in the ultrasonic bath?

    Leave a comment:


  • Dayboro
    replied
    I recently purchased an EM6910 the was not looked after at all.... the group head was a corroded mess....under the drip tray where liquid had overflowed was all caked up with powdery corroded aluminium from the painted surface all lifting.
    The steam and hot water spouts were clogged up completely.
    I had no choice but to take the top off and investigate. Upon removing the top I found that the brass/copper lines and manifolds were also blocked.
    I removed and pulled them all apart and put them in my Ultrasonic bath which brought them up like new.
    Being so impressed with the difference that made, I also put he group head screens and filter baskets through he ultrasonic.
    All pristine again.... im just now waiting on a new group head seal to arrive.

    Leave a comment:


  • Beevee
    replied
    Thank you for the help in getting my newly acquired secondhand EM700 cleaned and fully functional...
    The Vinegar trick helped..
    I did use a blank basket to get the hot water spout working... When I got it when I turned the Hot tap on water came out of the group head... I tried the turn both taps on and it didn't make much difference... but when I put the blank basket in and turned the tap on after a couple of goes the hot water started to come out of the right spout..

    I might add although I am a newby to this forum I do have a larger double group Simonelli Appia that I use in my Coffee Van.. so cleaning Coffee machines is an everyday occurrence for me..

    Leave a comment:


  • Javaphile
    replied
    It doesn't even require a search really, just a look in the appropriate Documentation section where you'll find both the user and maintenance manuals.


    Java "Alien what?" phile

    Leave a comment:


  • TampIt
    replied
    Originally posted by jimbojangles View Post
    Eep, ok. It's hard to know what's best - so much conflicting info on here and elsewhere about cleaning. Only use vinegar, never use vinegar etc etc.

    Perhaps I'll use the descaler through the group head and mild citric acid through the steam wand. I want to give it a nuclear clean before my first use, so perhaps I'll give it the one-of-everything method.
    Please DON'T use citric... Xanthine is 100% correct.

    I always use about 2 tablespoons (imperial ones, although I doubt that is too critical) of white vinegar per litre of "filtered water" (i.e. not the stuff from a tap - some of that is pretty horrible). That is about the same concentration of white vinegar the SB 6910 manual recommends*. I have been using it on virtually every machine (i.e. from brass boilers to stainless steel thermoblocks) I encountered since 1970 and it works, subject to needing a really thorough flush. +1 to Rawill - also, always use the cheap white vinegar as the dearer ones have all kinds of extra rubbish in them to "improve the taste" - I doubt the additions are as non-residual as the cheap stuff.

    Also, I would suggest you do not "nuke it" by upping the concentration. Perhaps double whatever the SB manual recommends in volume if you are convinced it needs it, although I would give it one "standard clean" and then flush it thoroughly and try it out. If the showerscreens were that filthy, hopefully the rest of the system isn't.

    Hope this helps


    TampIt
    *search for the manual on this site or hunt it down on the SB OZ site. It is somewhere on CS as Java"fount of all knowledge in earth and heaven"phile informed me when I inadvertently double posted it.

    Java"fount of all knowledge in earth and heaven"phile - always remember he is an alien, so he has a head start over all of us on earth in the latter realm...

    Leave a comment:


  • rawill
    replied
    Jimbo - Yes but!

    I prefer white vinegar, as it is easier to get the smell out, than using the Sunbeam descaler tablets. Seems to take an age to get rid of the residual smell taste from these tablets.
    At least that was my recent experience when I used a two tablet strength in an attempt to clean a blocked steam thermoblock.

    Add another if but vinegar/not vinegar supporter!
    Last edited by rawill; 13 April 2018, 07:33 PM. Reason: spelling/typo

    Leave a comment:


  • Xanthine
    replied
    I would avoid citric as it is a solid (dissolved in water) and is more likely to leave a deposit in the steam thermoblock when flashed to steam. Vinegar, on the other hand, contains acetic acid which is volatile and should leave minimal deposit, especially if the cheap 'synthetic' white vinegar is used. I believe this is just a few percent acetic acid mixed with water. Other vinegars (red wine, apple cider etc) would be more likely to contain dissolved solids which would be left in the thin stainless spiral tube through the thermoblock.
    The main dis-advantage of vinegar is the smell, which can taint the milk/coffee unless thououghly flushed out after descaling.
    Last edited by Xanthine; 13 April 2018, 03:53 PM. Reason: Spelling

    Leave a comment:


  • jimbojangles
    replied
    Originally posted by TampIt View Post
    Descaler - your call...
    Eep, ok. It's hard to know what's best - so much conflicting info on here and elsewhere about cleaning. Only use vinegar, never use vinegar etc etc.

    Perhaps I'll use the descaler through the group head and mild citric acid through the steam wand. I want to give it a nuclear clean before my first use, so perhaps I'll give it the one-of-everything method.

    Leave a comment:


  • TampIt
    replied
    Originally posted by jimbojangles View Post
    That did the trick, thanks! After a minute there were a few drops coming out of the hot water wand, then after 2 or 3 minutes, both steam and hot water were pouring out.

    Water now pumping through the group head too. Now off to buy descaler, detergent, new seal etc etc with renewed hope.

    Thanks very much noidle, Xanthine & rawill for your replies! Way to make a noob feel welcome.
    Descaler - your call, however if you use white vinegar it will also be safe for the steam wand system (standard descaler isn't according to the SB manual).

    Leave a comment:


  • jimbojangles
    replied
    Originally posted by noidle22 View Post
    Open the hot water and steam knobs and leave running for a minute or so.
    That did the trick, thanks! After a minute there were a few drops coming out of the hot water wand, then after 2 or 3 minutes, both steam and hot water were pouring out.

    Water now pumping through the group head too. Now off to buy descaler, detergent, new seal etc etc with renewed hope.

    Thanks very much noidle, Xanthine & rawill for your replies! Way to make a noob feel welcome.

    Leave a comment:


  • rawill
    replied
    Isn't this just the case with "In perfect condition" used machines.

    Same experience here with a 6910, and a 7000.
    But both are doing the job now after a bit of learning and tinkering, and also a new relay for the 7000.
    Which will not be the problem for the OP.

    Leave a comment:


  • Xanthine
    replied
    Hi and welcome to the CS forum

    A couple of suggestions which may help to get the pump primed -
    First, temporarily remove the water filter from the tank and fill fill it to the top with clean water, remove the shower screens and group handle and use the 'Manual' button to see if you can get a water flow.
    If, after several tries, this is not successful you may need to use a largish syringe with a suitable adaptor to force water into the water inlet with the tank removed while running the pump. 12mm black irrigation poly pipe is a reasonable fit from memory - you may need to use a bit of ingenuity to adapt it.
    Listen to the sound of the pump while doing this - it sounds loud and 'clattery' when running dry but quietens down if full of water.
    If none of these things work it is possible that there is a blockage in the water line from the tank to the pump or the valves in the pump are stuck requiring dis-assembly. There is a tiny nozzle opening inside the flow sensor which is prone to blocking with 'things' which grow in the clear plastic supply line when the machine has been left un-used for some time with water sitting in the lines.
    Once you get the water flowing give it a good descale and detergent flush (two separate processes) and either replace the tank filter of rejuvenate the old one with a salt water bath.

    Hope this helps
    Trev
    Last edited by Xanthine; 11 April 2018, 06:47 PM. Reason: typo

    Leave a comment:

Working...
X