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Thread: Upgrading UK LA steam pump on Sunbeam EM6910

  1. #1
    Senior Member
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    Upgrading UK LA steam pump on Sunbeam EM6910

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hello coffee lover's,
    Im pondering the upgrading of my sunbeam em6910 steam pump to a bigger 40 watt ukla, I can fit it suitably using some breville fittings,doing away with the copper spiral tubing, being a more powerful pump,would the steam production suffer or would the PCB controlled pulsing maintain a good flow?
    These steam pumps ( oem) are readily available,but I have several 40 watt pumps could use.
    cheers,
    Mick.
    Last edited by mulquemi; 9th March 2015 at 02:44 PM.

  2. #2
    Senior Member Xanthine's Avatar
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    Hi Mick
    Going by the circuit diagram in the service manual, both both the steam and the water pumps have identical drive circuits using the same MAC97A8 triac so the control board should be able to handle the extra load of the 40W pump. (This assumes that the 6910 board is the same as the one in the manual which is titled as EM6900)

    As you suggest, the main problem would be whether the micro could compensate for the larger flow rate from the new pump. The steam themoblock has an NTC themistor to sense its temperature. This may only serve to tell the micro that it has reached operating temperature on warm-up, with the pump duration and intervals being pre-set for the various steam settings. On the other hand, the thermistor may be able to provide feed-back to adjust for the larger pump.

    My guess is that the 40W pump has a much higher flow rate and this would simply swamp any attempt to control the steam by the micro, or the heater in the thermobloc would not be able to keep up with the water flow, with just hot water produced or, at best, very wet steam. One of the limitations of the trermobloc 'flash' boilers is the current draw from single phase 240v mains.

    Also, consideration would need to be given to the different output pressure of the new pump and whether this would affect the fittings in the steam line. I have not looked up the specs of the pumps but, from memory, they are considerably different.

    My guess is that the engineers who designed the machine optimised the components for best perfomance with the current draw available and not much would be gained by making the swap, especially in view of the amount of work involved in trying to safely shoe-horn in the new pump.

    An interesting question and it would be good to hear what others think.

    Trev

  3. #3
    Senior Member
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    Trev,
    Thank you for your detailed reply,yes I could end up with a perfectly operating em6910 ,after the modifications, on the other hand,I may have troubles also.
    I can always return it to stock if all come to no good,I have a spare machine so I'm not going to comprise my coffee indulgences.
    I will do the change over and keep you posted on proceedings.
    Thanks again for your knowledgeable /experienced deliberations.
    cheers,Mick.



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