Ulka Pumps Weakens/Hums - Page 3

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

So I finally received the Kill A Watt and plugged it in today. The initial reading is 118 volt and when the heating element turns on it drops to 114. Is that normal or even enough to weaken the pump? Should there be a drop to begin with?
Voltage sag of the mains under load is perfectly normal. It depends on the circuit. A 15-Amp circuit will sag more than will a 20-Amp circuit. A long run will sag more than will a short run to the panel. It also depends if there is some other load on that same circuit. Your voltage is a little low by modern standards, but it is within reason. For comparison, my Magister Stella on a 20-amp 40-foot dedicated circuit measures 121.1-Volts at no load and 118.3-Volts with the Magister heating. Given my results, I'd judge your readings to be about normal. Of course, as I pointed out earlier, this tells you nothing about the voltage across the pump. Did you do the test your machine on another circuit and/or at your friend's house yet? This will tell you a lot.

thecoffeefield (original poster)
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#22: Post by thecoffeefield (original poster) replying to Nunas »

That makes sense and I still haven't tested the machine anywhere as I'm focused on my place for now. Interestingly, in the morning (7am), the Kill A Watt showed 122v and with the heating element on close to 119v but the good news is, the heating element in this case didn't cause the pump to hum and it operated the same way as if the heating element wasn't on. This leads me to believe that the 116v I was getting yesterday afternoon (6 pm or so) was not good enough for the pump and the heating element to operate simultaneously but at 119v doesn't seem to be a problem. I'm still testing different times and different conditions. Does that make sense?

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thecoffeefield (original poster)
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#23: Post by thecoffeefield (original poster) »

wsfarrell wrote:Real long shot, but it doesn't cost anything to test:

I have an older machine where the pump would sometimes pump and sometimes just hum without moving water. After a lot of hair-pulling, I finally noticed that one of the connectors on the pump switch was loose. I tightened the connector and everything has been perfect since.
Thank you for that. I'm descaling the machine today and I will double check the pump connectors.

Nunas
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#24: Post by Nunas »

This leads me to believe that the 116v I was getting yesterday afternoon (6 pm or so) was not good enough for the pump and the heating element to operate simultaneously but at 119v doesn't seem to be a problem. I'm still testing different times and different conditions. Does that make sense?
Now that you have a meter to look at, you may become overly data conscious. You'll find the voltage fluctuates a lot through the day. It depends on the load in your home and your neighbourhood. If all the people around you are running air conditioners the voltage will sag. At supper time, if your area has a lot of electric stoves, it will sag. If you turn on your electric oven it will sag. When I was a boy the voltage was closer to 110-Volts (people still call it that today). Over the years the grid voltage has gradually been increased to the point where it is sometimes nearly 130-Volts. The currently accepted range in the USA and Canada is 114 to 126 Volts, which is nominally called 120-Volts. BTW, the power utility can change the tap on the transformer serving your home and raise the voltage. I'm not saying you need to do this, just pointing out that it is possible, as 116-Volts no-load is flirting with the low end of normal.

Frankly, none of this should matter much to your espresso machine. 116-Volts ought to be good enough. As I mentioned previously, a vibe pump pump produces far more pressure than needed, nominally 15-bar. You only use about 9-bar to make espresso. The excess is bled off and the water sent back to the reservoir. The voltage could sag quite a bit and the pump would still produce adequate pressure....if the pump is not wearing out.

thecoffeefield (original poster)
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#25: Post by thecoffeefield (original poster) replying to Nunas »

I think the issue can be divided into two questions:

First, What's causing the pump hum when the heating element is on? Second, Does the pump hum in this case affects the pressure/flow of water to the puck?

The answer to the first question I think I was able to answer using the Kill A Watt as I figured out that as long as the machine is getting at least 119 volt with the heating element on, then there is no humming. The second question I haven't been able to answer yet. I will need to do further testing and pull shots with and without the heating element on. If both shots have the same yield then I'm good to go and quite frankly the humming won't bother me but if the humming ends up causing me to get less coffee in the cup then the humming is affecting the extraction and in this case I will just replace the pump and get this whole thing over with. I understand your point that 116v should be fine to the espresso machine that's why if at 116v and the pump humming affecting the extraction then a new pump is the way to go. I will keep updating the thread with what I find out so that hopefully this can be helpful to someone else who may have the same issue.

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yakster
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#26: Post by yakster »

thecoffeefield wrote:That makes sense and I still haven't tested the machine anywhere as I'm focused on my place for now. Interestingly, in the morning (7am), the Kill A Watt showed 122v and with the heating element on close to 119v but the good news is, the heating element in this case didn't cause the pump to hum and it operated the same way as if the heating element wasn't on. This leads me to believe that the 116v I was getting yesterday afternoon (6 pm or so) was not good enough for the pump and the heating element to operate simultaneously but at 119v doesn't seem to be a problem. I'm still testing different times and different conditions. Does that make sense?
I think that the pump hum that you're noticing is probably due to the lower voltage when the heating element kicks on. 114 V is a bit low. Now that summer is here, you'll notice that the voltage will be lower during peak hours. I would look at what other appliances are on the same circuit breaker as the espresso machine and see if you can optimize things by moving things around. I avoid having my microwave and coffee maker on the same circuit and when I roast with my Behmor I plug it into the outlet at the washer/dryer that's a short run from the breaker box.

It is also possible that you have some loose connections on the outlets that makes things worse. Tightening these connections could help, but make sure that the breaker is turned off and there's no voltage on the outlet before working on this.
-Chris

LMWDP # 272

thecoffeefield (original poster)
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#27: Post by thecoffeefield (original poster) »

I just thought I would give an update on this. The humming of the pump DOES NOT affect the extraction/flow or volume of the shot. Initially, I was under the impression that the pump weakening causes the flow to decrease but after pulling multiple shots, the output was practically consistent, regardless if the pump hummed or not (it hums when the heating element is on). Hope this can help someone else with a similar situation.

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thecoffeefield (original poster)
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#28: Post by thecoffeefield (original poster) »

I just wanted to give another update and see if any one has any feedback or opinions on the issue before I go ahead and replace the pump. After further observations and using the machine at different times throughout the day, I realized that the pump weak noise is not necessarily linked to the heating element turning on. In many cases, the pump was humming and sounded weak when the heating element was off!

Also, I may have been mistaken in my previous post when I concluded that the humming/weakening of the pump is not affecting the flow. I was observing my flow from the bottomless portafilter once and noticed that when the pump noise level increased, the flow also increased and the shape of the cone became more pronounced.

I have already tried the machine on different outlets/circuits and still experienced the same issue. Will a pump definitely fix this or it can it be the OPV as well?

Any help is appreciated

Coffecapi
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#29: Post by Coffecapi »

I do have the same problem, any luck with the new pump?
Thks

thecoffeefield (original poster)
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#30: Post by thecoffeefield (original poster) replying to Coffecapi »

Yes, the new pump solved the problem.

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