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Pump pressure on Reneka Viva

Postby tutone on Tue Oct 28, 2008 1:46 am

Hi all. Been lingering on this site for a while, and I am amazed by the quality and depth of some of the posts.

We recently purchased a used Reneka Viva I for use at work. The machine sat for a while, and we disassembled and gave it a bath in citric acid. The machine works well, does not leak, etc... and makes fairly decent espresso.

The unit has 2 manometers on it, one for boiler pressure, and one for pump pressure (at least it is attached to the same line as the pump line is.) Despite the pressostat being a bit cranky, we have the boiler pressure set at roughly 1.0 - 1.1. Attempts to set it lower result in it dropping to .6, so we left it at 1.0.

We are trying to adjust the pump pressure, but are a bit stuck as to how to do this. We know where the adjustment for the pump is, but the manometer (machine turned on and at rest) shows about 4.0, which I take to be the pressure of the water service feed. When we put in the blank portafilter and press a button, I would expect the needle to rise toward 9 ish. However, it does not move. When making espresso, we see the same behavior with the manometer. I know the manometer works at least to some extent as I can see the needle move if the water for the adjacent sink is used (the needle wiggles a bit.) And if I turn off the water feed and bleed, it drops to 0.

If the pump were not making any additional pressure, I can't imagine we would be making anything drinkable, but the espresso is not too bad. So, we must be building pump pressure, but the gauge is not showing it. Right?

The 2nd manometer must show pump pressure, correct? If so why would it not move off of 4? We tried to put an additional gauge on the bottom of the portafilter, but the design of the Reneka portafilter just leaks. There are 2 grooves on the ridge of the portafilter (right below the basket rim) and water goes back up through there.

Any additional help than the wealth of information we have already received from this site would be much appreciated. Thank you.
-Tom
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Postby DavidMLewis on Tue Oct 28, 2008 2:28 pm

Hi,

Call Mike Johnson at Boyd's. He'll sell you a pressure gauge for (from an old and failing memory) around $40. It consists of a blind filter with an instant tube fitting in the middle, some tubing, and a pressure gauge that also has an instant tube fitting. This allows you, if you don't have a bottomless portafilter, to thread the tubing up through the spout. Good luck, although my money is on a bad pump.

Best,
David
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Postby tutone on Tue Oct 28, 2008 8:05 pm

David, I tended to agree with you that the pump was not operating properly, so I went ahead and pulled the pump. On a side note, this Reneka is so easy to work on.

Pulled the pump and figured out why it was so "quiet" when it ran. It was quiet because it was not spinning. The pump was a bit seized. Several turns with an adjustable got it moving again. The poor motor must have been straining. I'm surprised it did not go up in smoke!

Put the pump back in, and viola 12 bars of pressure. Adjusted down to 9 now.

So _now_ it is making espresso! What was it making before at 4 bars? I'm amazed that 1) it actually produced espresso at 4 bars, and 2) the motor did not burn out trying to spin this pump.

Thanks for the guidance!
tutone
 
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Postby DavidMLewis on Thu Oct 30, 2008 12:12 pm

Just so you know, pumps rarely heal themselves. Best order a new one while the old one is still working.

Best,
David
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Postby jhall350 on Thu Oct 30, 2008 1:36 pm

I also own a Reneka Viva I and had the same problem as you. I bought mine used and had to "unseize" the pump. The pump was useful for a while but as David points out, they rarely heal themselves. I ordered and installed a new one (from Boyd's coffee) and it is so much quieter and more consistent than the old one. I highly recommend getting a new pump.

Be sure to replace the dispersion screen (if it's dirty) and make sure the group gasket is still functioning properly. By that I mean make sure the gasket is still pliable and clean.

Paired with a good grinder I've had a number of very enjoyable espressos out of my machine. Like you, I totally rebuilt it and it's been humming along nicely for a couple of years now.

Good luck with yours and as an aside I ended up replacing the 4 hole steaming tip with a two hole replacement. I've had a much easier time frothing small amounts of milk with the two hole versus the 4 hole tip.
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Postby tutone on Fri Oct 31, 2008 1:34 am

Good recommendation to replace the pump, or at least get ready to replace it. The machine sat for 3 years before we got it, so I'm sure the years of inactivity were not kind to it. With about 12 people using this machine daily it will probably go sooner than later.

Jason, you hit the nail on the head. The group gasket is hard, and we have one on order, and the steamer is difficult w/ 4 holes. One of the espresso junkies here figured out how to get it to froth fantastically though. So now it is just a matter of training the other 11 espresso junkies.

He only froths enough for one cup at a time, and tips the container a bit with the tip angled near the edge. This gets the milk swirling pretty fast, and with 4 tips it heats up very fast, but in the last 2 seconds as it is heating it increases in size 2x and has great micro foam.

Time to start looking for a good grinder now. I fear this addiction will move toward bean roasting...
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Postby Denny Tryon on Mon Nov 24, 2008 2:30 pm

Hi all,

I also have a Reneka VIVA that I bought "used" and restored it.


It works great, but I am wondering about the gauges on the front.

I take it the left gauge is the steam pressure, and the right gauge
is the pump pressure.

What should be the appropriate settings of these gauges, at sea level
and how does one adjust these?

I am more of an "electronics" guy and repaired both the microprocessor
and electrical issues the unit had.

Any thoughts?

Thanks

Denny
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Postby HB on Mon Nov 24, 2008 3:16 pm

Denny Tryon wrote:What should be the appropriate settings of these gauges, at sea level
and how does one adjust these?

I don't know specifically about the Reneka Vivo, but the typical HX espresso machine steam boiler pressure is 1.0-1.2 bar (the Cimbali Junior is a notable exception) and the recommended brew pressure is 9 bar. The FAQs and Favorites links threads that describe how to regulate the steam boiler pressure and rotary pump pressure (search on 'pressurestat' and 'rotary pump' respectively).
Dan Kehn
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Postby jghoo on Sat Dec 20, 2008 9:14 pm

I realize this is an old thread. I put a PID in my viva to much success. I left the pressure stat hooked up. I used a spare capped off port on the left side of the boiler for the thermocouple. The boiler temp is now far more stable with much less deadband. I would highly recommend this mod for anyone using a viva. I can be more specific if anyone wishes. With its 5 litre boiler and 2100 watts this unit is a powerhouse. I really would like to pid the grouphead of this unit. If anyone has any suggestions plz speak up. Also the group gasket has a lifespan of around 6 mo so order multiples when you get them.
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