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Thread: Plumbing in a rotary pump machine

  1. #1
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    Plumbing in a rotary pump machine

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hi All,

    It looks as if I might be in the market for a new machine so I thought it would be the best time to upgrade to a rotary pump and plumb the supply water in. During our recent extension I ran some 1/4" poly hose from the kitchen island bench, under the floor to the coffee bench (about 3-4m). To their credit the cabinet makers cut a hole in the base of the cabinets and taped the hose to the back of the cabinet which makes my job a little easier. Now before I go to the expense of a rotary machine I just wanted to check that I have everything in place.

    This was what I was thinking:

    Under the kitchen sink I have the Brita C150 connected to a standard Goose Neck Faucet (for filling the old machine and general drinking water).

    I plan on inserting a three way 1/4" poly tee here and connecting the hose to the coffee bench with an inline isolation tap at this point as it will be the easier point of access.

    Under the coffee bench (which has drawers so access is available but will require removal of the drawers) converting the 1/4" poly to a 3/8" fitting (male or female depending on the machine).

    Then I was planning on cutting a hole in the plasterboard (brick veneer wall) and another in the back of the cabinet below the coffee bench to feed to braided hose from the coffee machine to 3/8" fitting.

    I was thinking of fitting a blank GPO plate in the plasterboard wall behind the machine and then just drilling a hole in it to feed the braided hose through for a neater finish. Doing it this way will avoid the need of cutting the bench top and if the machine ever needs to be moved its just a matter of patching the plasterboard.

    I don't have a plumbed waste (unless I move the entire operation into the pantry) but don't find emptying the drip tray to be too much of a problem.

    Bombora sell a domestic Tee Kit with the components that I need, but I just wanted clarification from those wiser than myself that the plan will work before shelling out the additional funds for a rotary pump version. I take it the braided hose aren't included with the machine.

    Cheers

    Stinky.

  2. #2
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    The rotary pump on my 2 group La Pav would pull the water through most filters way faster than the filter could handle. I ended up with a 3 litre "twice filtered rainwater" (i.e. no pressure) reservoir which the pump uses. BTW, my pump is adjustable for "low to mains pressure" - and it has to be matched pretty closely to work correctly. Perhaps newer pumps are less finicky?
    Sir_Stinkalot likes this.

  3. #3
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    Sir S where the Brita C150 converts from 3/8 to 1/4 poly pipe for the drinking water tap, I'd suggest your T it there
    and run the 3/8 braided pipe to your machine.
    Plumbed in machine's will generally have a set pressure / flow requirement.
    From my memory most are around 350kpa pressure / 5ltres a minute flow.
    Of course as replied above theres many ways to skin a cat .. !

    GL with your upgraditis shopping !
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  4. #4
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    I just plumbed my machine in recently and it was pretty straightforward. I'm using a Bombora filter instead of the Brita but I think the connection points are the same.
    Whatever machine you buy should come with the braided line and this will connect directly to the Brita head unit. The water inlet for the Brita should have the plastic tubing and a PLV that screws onto your T-piece. My T-piece services the dishwasher and coffee machine and has a shut off valve that closes both outlets.
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  5. #5
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    Also be wary of BSPT vs NPT as they are not compatible
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  6. #6
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    Thank you all for the replies ..... seems like it was worth asking the questions before committing to a rotary model. I should have mentioned that the machine I had in mind at this stage was the Rocket Giotto Evoluzione R.

    Below is the current setup for the Brita C150 (sorry I cant get it to rotate). The cold mains is coming through the base of the cabinet to a Tee and isolation tap. The box to the right is off to the dishwasher. To the left is another Tee with an isolation to the Brita and the braided hose is off to the kitchen sink mixer. The blue 1/4" poly goes to the Brita, and then the white 1/4" poly from the Brita to Goose Neck Faucet.

    Of the other blue 1/4" poly that are coiled behind the waste, one is run over to the coffee bench, and the other to the fridge. Neither are currently being used and were just put in place should they be needed one day.

    Unfortunately I will need to feed the machine from the blue 1/4" poly or nothing at all. The house is on a ground slab, then timber battens, hydraulic heating in polystyrene trays, then solid timber floorboards - I have no intention of trying to run anything else under the floor now its finished . Running a blank conduit through might have been a better idea but space and time were limited so I just ran the blue 1/4" poly. I could potentially use the 1/4" poly as a pull through for something larger if needed however I run the very real risk of snagging on something on the way through and losing the existing feed and ending up with nothing.

    So I guess the question now becomes if the Rocket Giotto Evoluzione R can be directly plumbed from the Brita C150 via 1/4" poly.
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  7. #7
    Senior Member saroadie's Avatar
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    G'day, speaking from experience of my plumbed in Izzo Alex Duetto (which is connected via 3/8" because I just did it that way due to the sizes on the Brita C150 and the Izzo Braided hose - not for any flow shortage):

    I think you'll be fine with 1/4" feeding your machine. I cant't imagine you're ever extracting water from the machine faster then it'll be supplied. The hot water tap is the fastest way to extract water from the machine and this is done by boiler pressure not inlet flow. The inlet flow just determines how fast the boiler is refilled. Pulling a shot - well with the rotary pump on, the flow rate is definitely way less than what I'd imagine a 1/4 pipe will supply. So in short, I don't think it would be an issue at all. Just make sure there's a 350kpa PLV in the system somewhere.

    You could always ask Bombora their opinion but I'm sure I've seen coffee machines plumbed with 1/4" in the past. I've definitely seen refrigerators with in-the-door chilled water plumbed with 1/4' and that works fine. I reckon this would use water faster than a coffee machine.
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  8. #8
    Senior Member Lyrebird's Avatar
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    Assuming the 1/4" line has .040" walls and thus an ID of 0.170", you'll get about 2.75 l/min for a 1 bar pressure drop over 3 metres of line.

    The dimensions are guesstimates, if you provide real numbers I can redo the calculation. The tube dimensions are for standard John Guest type water line which looks to be what you used.

  9. #9
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    Thanks again all for the responses.

    I have just tested the flow out of the filtered water tap that is currently run off the Bitra. Itís coming in at 3.75l/min.

    The blue pipe details are:
    Inside diameter = 4.1mm
    Outside diameter = 6.35mm
    Might be slightly off but should be close enough to the standard size (sorry I canít work in imperial).

    I do have extra of the white pipe (which measures and feels the same as the blue) and it has the following written on it:
    Aquapro 1/4Ē LLDPE Tube

    Length of pipe run to coffee machine = 5.8m.

    I purchased the pipe at a specialist water place and it does work with the John Guess (?) fittings.

  10. #10
    Senior Member Lyrebird's Avatar
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    That calculates out to a pressure drop of around 4 Bar, which is pretty close to standard domestic water pressure.
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  11. #11
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    So its looking fairly positive so far

    Thanks for the efforts with the calculations Lyrebird ..... in general terms what does the pressure drop of around 4 Bar do to me?

    I'm not sure if I can provide a direct link to Bombora however they have an article about Domestic Coffee Filters. In this they have a break down of the various options - one of the scenarios is:

    I want the C150 kit (or have a suitable system) BUT want to also TEE off to plumb in my machine...

    The TEE kit creates a flow path after your filter to your coffee machine. The kit includes fittings to suit both male and female machine inlets and will fit easily to most braided hose connections provided with the coffee machine. The TEE kit also includes an isolation tap and 2 metres of 1/4" poly hose (please advise if more than 2 metres is required).


    I think this is why I got the idea of running the 1/4" poly.

    I did find a good YouTube video last night where Seattle Coffee Gear described plumbing a Rocket machine and due to the different hose connections in the USA they sell a conversion kit which includes a long length of poly hose (they didn't detail the size). Perhaps not something to be taken as gospel but they at least went to the detail of what you need to do - something I cant seem to find on Rockets own website.

    Looking more closely at the options it does seem to indicate that there should be a Pressure Limiting Valve 350KPA before the filter (which I am currently missing). How do you determine if the PLV is required. I would have assumed that pressure would vary greatly from house to house.

  12. #12
    Senior Member Lyrebird's Avatar
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    The 4 bar drop by itself doesn't mean anything.

    Assuming the machine you are plumbing in uses a standard Fluid O Tech rotary pump (or similar) it will pull water in at about 3 l/min when filling the boiler(s) and a small percentage of that when pulling a shot.

    The idea is to make sure that the water supply can keep up with the inlet rate when the boiler is filling, your 3.75 l / min sounds like you'll be fine.

    When pulling a shot the flow rate is much lower, the pressure drop reduces accordingly so pressure at the pump inlet will be much higher (approximately equal to the supply pressure) which is where knowing that your supply is running at around 4 bar is useful.

    It is my understanding that the usual routine is to adjust the pump bypass so that it gives the correct grouphead pressure with an inlet pressure of 350 kPa (approx 3.5 bar) and then limit the supply pressure to this figure with a pressure limiter (regulator).

    Since you are close to the correct pressure you may be able to get away without a pressure limiter, assuming the value you measured is typical and the variance is not too large.

    On the other hand if the filter manufacturer requires an inlet pressure no greater than 350 kPa then you will need a pressure limiter in order to stay within spec.
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