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Thread: BZ99 issues pumping while hot

  1. #1
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    BZ99 issues pumping while hot

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hi all - here's another old BZ99 with a few issues.

    My machine - bought through CS a couple of months ago - will work fine at first after starting up from cold. Give it 10 minutes to warm up and everything goes well and I've managed some good shots.
    If you leave it to heat up for a while (e.g. half an hour or so) - the pump no longer pumps. It'll make noise but it won't actually pump anything - nothing out of the group head other than whatever's left in the HX, and if the boiler needs filling, the pump just runs continuously until I turn the machine off. Once it's cooled down it'll pump again

    I've pulled apart, cleaned and tested the HX water/boiler fill system - I'm pretty sure there's no blockage and the 2-way solenoid is working fine. And the electrical/control system seems to be working properly. The problem must have something to do with the boiler getting up to temp and/or the whole machine having heated up. I have a few theories but I'm struggling to see what would cause problems for a pump that is otherwise able to supply full pressure when it's not so hot.

    Does anyone on here have any ideas for what could be causing this?

  2. #2
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    Does anyone have any ideas about this? Any theories, ideas, advice appreciated!!!

  3. #3
    Mal Dimal's Avatar
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    Hello Dave...

    Could very well be the pump. How old is it?
    When the pump seems to be running but not producing flow, do you notice any water being returned to the water tank or the drip tray, from the OPV bypass line?
    When you say that you have verified the 3-Way Valve is Ok, how did you do this?

    Just a few questions to get started...

    Mal.

  4. #4
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    Hi Mal
    Was hoping youíd reply having read your other helpful posts

    I reckon the pump is probably as old as the machine I.e. maybe 10-12 years. Not sure exactly.

    When itís doing its thing I donít notice any flow in those places you mention. Plus I can put my finger over the outlet valve in the water tank and tell that itís not sucking any water - when itís working properly there is a strong suction there.
    I managed to test the boiler fill solenoid valve that either sends water to the HX or boiler fill by disconnecting the piping out of the valve and observing water flow either by pushing the brew button (valve closed) or making the boiler try to fill by disconnecting the high level water probe (valve open). Seemed to work as expected albeit I only tested it while the machine was cold.

    I havenít tried actually testing the 3 way solenoid valve between the HX and group head but it all seems to work as I would expect. For example if I push the brew button while the boiler is trying to fill I get water & steam coming out of the group head, presumably just whatever is left in the HX but at least it shows the valve is open...

    Part of it is just that I have tried to think through what should happen under various scenarios and it all seems to suggest to me that I am not getting flow from the pump itself rather than something else being closed or blocked. But I am new at this and could definitely be wrong.

    Thanks
    Dave

  5. #5
    Mal Dimal's Avatar
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    No worries mate...

    I'd reckon, given the age of the pump, there's a very good chance that the piston/bore clearance may be excessive once things warm up. Wouldn't hurt to grab a new one from Coffee Parts or from another Site Sponsor; an inexpensive and worthwhile thing to do.

    Mal.

  6. #6
    Senior Member Jackster's Avatar
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    So you tested the fill solenoid when cold, at the output, and it works...

    So now test the pump output at the out of the pump. Compare flow volumes when hot and cold.

    Maybe the nose of the pump needs pulling apart and cleaning?

    My pump had a bit of shiz in the ball valve inside the nose. It caused intermittent flow issues.
    Worth cleaning before replacing pump.
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  7. #7
    Mal Dimal's Avatar
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    Probably a good idea to still buy a new pump, then overhaul the original to keep as a backup...

    Mal.

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    Thanks guys. I will have a go at the old pump over the weekend and probably order a new one too unless I find something really obvious & fixable.
    Looks like $100 for a new fluid-o-tech pump from coffee parts.
    Cheers
    Dave

  9. #9
    Mal Dimal's Avatar
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    Can't replace it with one of these, eh?
    https://www.coffeeparts.com.au/61716...ad-outlet-220v

    Mal.

  10. #10
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    Yeh - but if you get 10/12 years out of it (which I doubt you'd get out of an Ulka) - I say - why not? Saves buggering around with trying to make it work too... Dunno - just my view on it.

  11. #11
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    Yeah Iíve seen places selling Ďconversion kitsí with the Ulka plus a few fittings for about $100. Havenít added up coffeeparts prices for the same gear but if itís close Iíd just stick with the original version.

  12. #12
    Mal Dimal's Avatar
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    Never had issues with Ulka pumps...

    More than 10 years life is not uncommon.

    Mal.

  13. #13
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    Right - first I tested the pump some more. I let the machine heat up and it wasn't pumping. Then disconnected the outlet pipe and it starts pumping ok, so connect it back up and its working fine again.
    Let it heat up again and it's not pumping again.
    I then pulled the pump out and apart. It was manufactured in 2005 so 13-14 years use. Nothing obviously wrong or blocked in the flow path but it obviously has a bit of a leak at the inlet and outlet flanges and the inlet gasket is split.
    I think I'll get the new pump and give it a go. Probably just stick with the Fluid-o-tech - looks pretty solid from the inside

  14. #14
    Senior Member Jackster's Avatar
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    Is the fluid o tech, plug and play? It looks to have different connections electrcally- looks to take a solonoid type plug.

    What about piping, Are they the same?

    For ease, I'd put in a replacement ulka, as Mal suggested...

  15. #15
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    Hi Jackster
    It has a fluid o tech pump now, so that would be the direct replacement.
    Fitting the Ulka would involve more fiddling - piping and the electrical connection are different - albeit it would probably end up cheaper overall.
    Iím leaning towards like for like just to keep it simple.
    Thanks
    Dave
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  16. #16
    Senior Member Jackster's Avatar
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    Oops, I missed that. Rereading your posts 10 and 11, I see you suggested yours was a fluid o tech.

  17. #17
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    All good. I have ordered the pump, hope it comes quickly! The old one is leaking after I pulled it apart.... doh!
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  18. #18
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    Hi all, my new pump arrived today and itís all fitted. Seems to be working fine but I will put it through its paces over the coming days.
    I did have a nervous moment when it wasnít pumping for a bit but I think that was due to a kink in the (fairly rigid plastic) inlet line which I have sorted out.
    Also got a nice new set of scales for good measure which will help my routine no end!
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  19. #19
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    Well - hopefully CrankyDave will no longer be cranky, but HappyCaffeinatedDave.
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  20. #20
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    If only caffeine would solve all my problems...

    I left the machine to heat up for a while this morning before running the pump and it all works well - so Iím calling this problem solved.

    Since putting the new pump in I have noticed that it seems to Ďsurgeí periodically when pulling a shot - just based on pump noise; I donít notice anything in the shot itself. Has anyone had any experience with that?

  21. #21
    Senior Member Jackster's Avatar
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    I say that if it's surging it's running the correct pressure and so also pretty close to the correct grind.
    I have a video of my old Breville 800es cycling, for you to compare. There also is a clip of my Musica not surging. Turns out it had a pump issue and low pressure. The Musica now surges like the Breville did.

    https://youtu.be/CR8yxCSZ_v8
    Surging at 36-50sec... Skip the rest

  22. #22
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    Thanks Jackster - thatís very similar to what mine is doing.

  23. #23
    Senior Member Jackster's Avatar
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    I believe what is happening is the pump is on its limit spring. The piston is at its retracted position with a full head of water in front of it. The electric field is not strong enough to push any more water (like a bike going downhill, the pedals are going round, but not doing anything much, just freewheeling along).

    Or something similar. Someone here may actually know what's going on. I haven't cared about it that much. But I know if you pump isn't surging like that, there is some room for improvement.

    The 800es never surged till I got a settee 270w grinder. The Musica didn't surge, and when I checked it's pressure, it was around 6bar. If you have a opv, i think it still needs to surge or the opv needs checking/setting. I fitted a opv to mine, and it's set to a leaking 9bar @ group (so slightly more if not leaking, like when pulling a shot)

    This is all my opinion from a short time observing, playing with only a few coffee machines. YMMV.

  24. #24
    Mal Dimal's Avatar
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    You shouldn't be getting any "pump surge" if your shot prep. is on the button.
    The pump should slowly change pitch as the head pressure builds and then remain constant once the OPV takes over control of the brew circuit pressure.

    Any "surging" would indicate that maybe your shot prep. isn't spot on, the OPV is behaving erratically, the pump intake is being restricted or the pump has a problem.

    Mal.
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  25. #25
    Senior Member Jackster's Avatar
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    Quote Originally Posted by Dimal View Post
    You shouldn't be getting any "pump surge" if your shot prep. is on the button.
    The pump should slowly change pitch as the head pressure builds and then remain constant once the OPV takes over control of the brew circuit pressure.

    Any "surging" would indicate that maybe your shot prep. isn't spot on, the OPV is behaving erratically, the pump intake is being restricted or the pump has a problem.

    Mal.
    Giving this some thought, and watching some utube vids, and more thoughts...
    Coffeeparts have delivered me a new pump for my Musica. Also a 18g vst ridgeless to fill the box.

    I think you are correct Mal. Will fit the pump today. I mean, my electrician buddy will fit it.
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  26. #26
    Senior Member Jackster's Avatar
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    New pump, no surge...thanks Mal. Next!
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  27. #27
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    Hi
    Mine does surge - sometimes. I suspect it might be due to a kink in the inlet hose pulling closed under heavy suction. Does anyone know if itís possible to remove the fitting on the ends of these hoses & refit them? Thereís a metal plug in the end of the hose that looks like it could be pulled apart, but I didnít want to damage it by trying too hard.

    Apart from that, my machine is going well with no sign of any pumping problems while hot.

    Thanks
    Dave

  28. #28
    Senior Member Jackster's Avatar
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    There will be no suction in the inlet pipe when pulling a shot. There is almost no flow at that time.
    The highest pipe flow will be when pumping out the group without no coffee.
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  29. #29
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    I have been having fun with my machine lately.
    Last week it started tripping the RCD as soon as I turned it on. At first I thought of a water leak but eventually confirmed the heating element had gone.

    Ordered a new element from Barazi along with a couple of bits and pieces and itís all good again. Great service from them, ordered on Monday and parts delivered to Perth on Wednesday.

    I think this machine must have sat idle for a while before I bought it and I am stressing old components by using it regularly again. Fortunately parts are readily available, reasonably inexpensive and the thing is easy to work on.

    Looking forward to a nice espresso tomorrow morning, hopefully nothing else breaks!
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