Seized pump in Profitec Pro 700

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
neutro
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#1: Post by neutro »

Hi guys. I don't post that often anymore because I reached steady-state espresso production with my setup a while ago and everything has just been... well, fine.

Last weekend, I hit a snag though as my Pro 700's rotary pump was making a bit more noise than normally and suddenly stopped working with a "clunk". Now each time I activate the pump, I hear a small "clunk" and only hear a slight electrical buzz (with no water coming out of the brew group).

Machine is plumbed in, so I do get a few drops, but of course the general symptoms (clunk & buzz with no pressure) are the same using the reservoir.

I just wanted to confirm the most logical course of action considering the pump is likely to be seized. I would have done as in this video first (which shows exactly what I'm experiencing but in an Expobar machine):
but in the Pro 700 the pump is the other way around, so I don't have easy access to the motor shaft.

I guess I should then disassemble the pump first and try to unjam it by turning the shaft (and/or try the same with the motor once the pump is out of the way). If I can unjam a stuck item, that would be nice, but else ordering it new would be the most logical course of action.

Waiting for other suggestions or a few thumbs up before proceeding... Thanks for any hint as always.

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BaristaBoy E61
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#2: Post by BaristaBoy E61 »

So you say your machine is direct plumbed in, right?
What's the pressure readout on the pump gauge; does it show waterline pressure?
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

Giampiero
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#3: Post by Giampiero »

Maybe is just the capacitor ( the white cylinder on the top of the motor) that has blown?

neutro (original poster)
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#4: Post by neutro (original poster) »

BaristaBoy E61 wrote:So you say your machine is direct plumbed in, right?
What's the pressure readout on the pump gauge; does it show waterline pressure?
Yes the line pressure is there (a bit below 1 bar on the gauge) and drops to zero as I open the valve and let the water flow.

Line pressure after my pressure regulator is supposed to be 25 psi (1.72 bar). I'm not sure if the pressure reduction I see is due to the machine internals, or e.g. inaccuracy in the gauge at low pressures (it's basically at the first tick, and those are weirdly divided on the original Pro 700, but that's another topic).

To make a story short, when I cut the water to the machine, the pressure gauge drops to zero, so I see a difference with the water on.
Giampiero wrote:Maybe is just the capacitor ( the white cylinder on the top of the motor) that has blown?
I doubt it because I don't see any damage, don't smell the typical fried capacitor smell, and gather that the "clunk" I hear when I turn the pump on is due to the torque provided by the capacitor peak.

Still, it's on the list of things to check out I guess.

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HB
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#5: Post by HB »

neutro wrote:I just wanted to confirm the most logical course of action considering the pump is likely to be seized.
I saw this once; it happened to an espresso machine that was unused for a long time. I separated the motor and pump - the motor spun up easily, but the pump was stuck. A half turn and it was good to go. The trick suggested by WholeLatteLove's video above is a good one, i.e., try turning the shaft of the motor with the slotted end, if possible.

By the way, if the pump doesn't start immediately, cut power or you risk damaging the motor windings (or so I've been told :)).
Dan Kehn

JRising
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#6: Post by JRising »

You probably already know this, but separate the pump from the motor so that you can turn both by hand and confirm which is seized, or if the motor simply isn't running.

If the pump is turnable but seizes up at a certain position, then it's possibly something riding around inside the pump (and stopping it when it jams between the walls)... If so, you can flush water through the pump backward while turning the shaft back and forth, hoping to flush out whatever is in there. If it is a broken vane, there are people who rebuild these pumps, but that too is expensive.
It's unlikely that a foreign object got in there since you use the machine plumbed in, but if you can flush it out it may satisfy your curiousity.

neutro (original poster)
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#7: Post by neutro (original poster) »

Ok so since turning the shaft of the motor is not possible, the next most logical action I guess would be remove the pump. Hopefully it's doable without removing everything above (brew boiler assembly). Indeed then I'll be able to see if the pump is stuck, the motor is stuck, or something else is happening.

It might be a while before I have the free time to do this, but I'll report back with what I find.

neutro (original poster)
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#8: Post by neutro (original poster) »

A quick question regarding rotary pump removal before I proceed though.

On the inlet side, the braided hose from the selector valve connects to a series of 2 L-pipes that are connected to the pump inlet.

On the outlet side, there is a T where a braided hose goes to the brew reservoir and a capillary tube goes to the pressure gauge.

Should I disconnect the two braided hoses and the capillary tube, leaving the Ls and T connected to the pump? Or should I rather disconnect everything from the pump itself, leaving the hoses and capillary tube connected to the Ls and T?

Simply wondering if there is an advantage going one way or the other. The fittings seem smaller and more accessible on the hoses and capillary...

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BaristaBoy E61
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#9: Post by BaristaBoy E61 »

If the pump is connected with flexible hoses that have enough play, I would just separate the pump from the motor just to see if the pump motor by itself functions properly. If the pump buzzes and does not turn, kill the power to the pump as you are likely in 'Locked Rotor' mode and drawing maximum current to the motor 'Locked Rotor Amps' (LRA) that without over-current protection or thermal protection will burn the motor out in short order.

If the motor turns freely and normally, proceed to pump disconnection and removal for further investigation.
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

JRising
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#10: Post by JRising »

neutro wrote: Should I disconnect the two braided hoses and the capillary tube, leaving the Ls and T connected to the pump? Or should I rather disconnect everything from the pump itself, leaving the hoses and capillary tube connected to the Ls and T?
Yes, the braided hoses must be removed first. I would loosen the braided hoses first, before you even loosen the clamp that holds the pump to the motor, that way the machine is holding the pump steady as you work inside.

The fittings in the pump would need to be unscrewed 8 or 9 full rotations out of the pump and that can't happen if the hoses are still connected. If you do have to remove the fittings, you can do that outside of the machine where it will be much easier.

Have a box of bandaids near-by. You will probably cut two knuckles on sharp sheet metal your first time. (If not, I salute you)