Today, I did my first descaling of Valentina. It seemed to go well, although it took about 3 boiler flushes to get the taste totally gone.

Anyway, now that I'm done, the machine's pump seems to be acting really odd. It sounds pretty normal when I free run it, but when I put the backflush disc on, it bogs down to the point of near silence. Not only that, but nearly nothing comes out of the overpressure valve... I don't really know what to think. I'd adjusted it not long ago (maybe less than a month) to the generally recommended ~2-2.5oz/30sec. So, if the OPV valve is suddenly off, that would be really weird, because I think it would have to go from being set at ~9 bar to 14 or 15 bar, whatever that pump caps off at.

Does a pump get "tired?" I know Dan's mentioned that these pumps are intended to be 30-sec on, 30-sec off, and I'd imagine that it ran for longer than that a few times filling the boiler up... I haven't broken my pump, do you suppose? Espresso performance is OK, I guess... it's acting physically pretty similarly, except the pump sounds a lot more labored and quiet during the pulls. but, roughly the same volume shots at the same grind and tamp pressure.

I can't comment much on taste, it's been sourish so far. the manometer started showing, after I descaled, that the pressurestat was cycling from 1.1-1.3 bars, where it had previously been cycling 0.9-1.2 or so... and I simply adjusted it down. The shots are a little acid-y so far.

Is such strange behavior typical of a descaling? Could my OPV be way off from the de-scaling? Any ideas?

Well, a few hours later that night, the boiler seemed to be acting normally again.

This morning when I got up, I recalibrated the OPV with it acting normally and made a fantastic (for me) cappuccino.

So, what the heck? the pump was working, but it seems like it just wouldn't go up to high pressure--by the looks of it, it was maxing out below 9 bars last night (as it wasn't pushing through the OPV, which was set about there). Is that a common thing for a pump when it gets over-used? should I be worried about that, or should I just know that I have to let it "recover" before I start brewing shots after descaling it?

all this makes me want to get a rotary vane pump... are there any sources to find general guidelines for this upgrade? I'd do it in a snap if I wasn't worried about how the wiring would work out--that is, if I could get a motor for the pump that wouldn't make the machine draw too much current for the circuit it's on. I'd also be worried a little about mounting the thing in Valentina, although I think it could be done in light of that I don't use the internal reservoir anymore, being as I leave the machine on most of the time...

shadowfax wrote:all this makes me want to get a rotary vane pump... are there any sources to find general guidelines for this upgrade?

I've not seen a step-by-step guide, though Sean Lennon has talked about putting one together for converting the Expobar Brewtus. There's lots of mini-discussions that could be cobbled together:

Questions about converting from Vibe to Rotary pump
Rotary pump conversion leads to 'Rituale suicide'?
Banishing the noise - vibe to rotary conversion
Help choosing a check valve as part of rotary pump upgrade
Pump retrofit for Isomac Millenium (claycritters.com)
Isomac Rituale - Rotary Pump? (alt.coffee)

Needless to say, it's not as simple as removing a vibratory pump and putting a motor / rotary pump in its place. I outboarded Valentina's pump:



It's inelegant, but effective and inexpensive. An external rotary pump would be even quieter.

Well, Thanks, Dan. That was extremely informative. I e-mailed Jim at 1st-line and he pointed out that, although he thought it would be very, very feasible to add a rotary pump into Valentina, powered on the same relay as is in there now, it would have to be outboarded. Looking at the inside of Valentina, it looks like I would have a roughly 10" x 8" x 3.5" space in which to fit everything... ample volume, I think, for the pump and motor, but not anywhere near enough depth. I think that outboarding would be a pretty cool thing to do--I'd kinda like to build a box and mount a procon pump and a flojet in the box along with everything else, and then just have a 5 gallon tank input to that and run the wires and the high-pressure line running out back to the machine itself.

On the other hand, I think I've figured out more or less what's really troubling my vibe pump--the heating element comes on in the middle of shots/when I backflush if I don't pay attention and start at the top of a boiler cycle. For some reason the heating element does a nasty number on the pump when it comes on, making it bog down to the point it can't pump out the OPV when I backflush. I don't remember it losing that much power ever before this descaling.

Jim (again, from 1st-line) mentioned to me that the other concern (other than being able to empty the boiler of descaling solution) to descaling a vibe pump HX machine is that filling the boiler repeatedly can damage the pump from overuse.

At any rate, the pump is still working. I shouldn't let it be under pressure when the boiler comes on anyway, more than likely. It fits well into my routine to flush the HX, which usually makes the boiler tick on, and then wait the extra 4 or 5 seconds before starting to brew... the heating element seems to stay off if I do that. So, I think I will live with what I've got until the pump breaks--I have a sneaky feeling it will be the first thing that does--and then get a rotary pump and plumb in/go flojet then. I'm making great coffee right now. I revisited my packing method last week and it's made my shots much better and more consistent... I really can't begin to justify the upgrade at the moment, other than the old "just because I can!"

shadowfax wrote:Anyway, now that I'm done, the machine's pump seems to be acting really odd. It sounds pretty normal when I free run it, but when I put the backflush disc on, it bogs down to the point of near silence. Not only that, but nearly nothing comes out of the overpressure valve... I don't really know what to think. I'd adjusted it not long ago (maybe less than a month) to the generally recommended ~2-2.5oz/30sec. So, if the OPV valve is suddenly off, that would be really weird, because I think it would have to go from being set at ~9 bar to 14 or 15 bar, whatever that pump caps off at.

Does a pump get "tired?" I know Dan's mentioned that these pumps are intended to be 30-sec on, 30-sec off, and I'd imagine that it ran for longer than that a few times filling the boiler up... I haven't broken my pump, do you suppose? Espresso performance is OK, I guess... it's acting physically pretty similarly, except the pump sounds a lot more labored and quiet during the pulls. but, roughly the same volume shots at the same grind and tamp pressure.

The strange thing is that my Ulka on my Expobar does exactly the same thing. I first noticed this after backflushing. I actually replaced the first Ulka because of this same problem and the new one exhibited the same problem within a month or so. What I have found is that the temperature of the water greatly affects the pump's performance. I leave my machine on 24/7 and the water in the reservoir can get quite warm (in excess of 100F). With warm water in the reservoir the pump can only reach 8bar. However, with cold water, the pump is able to reach full pressure and the excess water drains through the OPV. I haven't been able to figure the reasoning behind this, but the pump has consistently acted this way for at least 6 months now.

shadowfax wrote:Anyway, now that I'm done, the machine's pump seems to be acting really odd. It sounds pretty normal when I free run it, but when I put the backflush disc on, it bogs down to the point of near silence. Not only that, but nearly nothing comes out of the overpressure valve... I don't really know what to think. I'd adjusted it not long ago (maybe less than a month) to the generally recommended ~2-2.5oz/30sec. So, if the OPV valve is suddenly off, that would be really weird, because I think it would have to go from being set at ~9 bar to 14 or 15 bar, whatever that pump caps off at.

Does a pump get "tired?" I know Dan's mentioned that these pumps are intended to be 30-sec on, 30-sec off, and I'd imagine that it ran for longer than that a few times filling the boiler up... I haven't broken my pump, do you suppose? Espresso performance is OK, I guess... it's acting physically pretty similarly, except the pump sounds a lot more labored and quiet during the pulls. but, roughly the same volume shots at the same grind and tamp pressure.


Is such strange behavior typical of a descaling? Could my OPV be way off from the de-scaling? Any ideas?

(old thread bump!)

interesting.. i descaled yesterday and am getting the same behavior. boiler fill is normal sounding, the first part of the shot sounds normal, but when the pump would typically get a bit more quiet (around the 10 sec mark, when coffee starts to flow), it gets REALLY quiet. i checked all rubber tubing and its fine. im wondering if there is a clog in a copper return line, or maybe the pump is on its way out. any way to tell? my home made gauge is telling me im around the 8bar mark, which is a bit lower than normal. ill try to bump it up and see if it reads higher. does the opv fail? anything else im not thinking of?

same thing happens with backflushing too.

thanks..

I have to say, after awhile it seemed to go away. I think the pump really did get overstressed by the amount of pumping you have to do to flush out that big tank... so, you should think about a rotary conversion, right? I think it could be done if you cut out a square in the back of the casing, where the big pump would stick out from its mounting on the front wall of the water reservoir housing.... It would look like those hot rod cars with the holes in the hood.

shadowfax wrote:so, you should think about a rotary conversion, right? I think it could be done if you cut out a square in the back of the casing, where the big pump would stick out from its mounting on the front wall of the water reservoir housing.... It would look like those hot rod cars with the holes in the hood.

lol.. im all for modding, but if i needed to move the machine, or disconnect for descaling, i think it would be even harder than my toilet bowl tank setup now.. :p

BTW, didnt mean to sound as if my problem went away. my pump is still getting super quiet on 'demand' loads, and backflushes. it fills the boiler fine though.

any way to rule anything out? im paranoid my machine will die and i wont have coffee, or, worse yet, something is wrong and im making worse coffee! lol

I would suggest you try paying attention to the heating element activity as you brew. I noticed on valentina that the pump worked a LOT better when the heating element was OFF... I think it has to do with the power draw of them both, together, being a little more than the circuit can deliever for... If I understand right, this is one reason that a 220V machine is better--you can supply the element and pump concurrently much better.

However, to ensure "mutual exclusion" of the pump and the heating element, try this. When you flush, you'll notice the element comes on from the pressure drop that accompanies the introduction of the cold flush water. Usually, it will still be on when the flush is finished. Try locking in your prepared shot right then and start it before the element goes off. This way, more "cold" water comes in before the element goes off, and it takes it a little longer to get all the way back up. And In my experience, the heating element goes off about 5 seconds into the shot, meaning it goes off before the pressure ramps up and the pump bogs down. The effect of this means the element doesn't come BACK on until late in the shot, about 25-30 seconds in, when you're about to kill it... and that usually means that the pump will have higher pressure on it. Just an idea to try. I don't know how temperature stable this idea is, I never had the tools to check it...