Mini Vivaldi steam boiler overfill, please help. [ISSUE REOPEN]

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Mini Vivaldi steam boiler overfill, please help. [ISSUE REOPEN]

Post by Tuk123 » Wed Aug 08, 2018 11:11 am

Hi,

I have very little knowledge of the inside of the machine, hopefully someone can point me to the right direction.

The issue is whenever I turn on the boiler for my mini, the pump engages. After awhile, water leaks out from the vacuum break valve at the top of the tank and shortly thereafter from the pressure safety valve behind the tank. The pump remains engaged the entire time. Eventually it shuts off by itself and all lights go off except the blinking boiler light. Based on what's stated in manual, I assume it's because the pump was engaged for over 60 secs?

It started after descaling the boiler. I had to replace the pump, so decided to descale. I removed the breaker and siphoned the water out. Pour in descale solution and breaker put back in. I then turn the boiler on and notice water leaking out, I realized that I forgot to wrap the valve with plumber tape. So I reinstall the breaker value, but this time with tape.. a very liberal amount of tape. Once the boiler is turn back on again, that's when I start noticing water out of the safety valve and my mini had never been the same.

I searched the forum and found discussions on corroded crimp connectors. I checked mine and all the plastic insulators were in bad shape. So I cleaned the connectors as best as I could and replace all the plastic caps with high temp silicone tape. The issue went away and I was able turn on the boiler and steam, at least for awhile until this morning.

I should add that if I turn off the boiler, the pump stop. Also on the bright side, I can still pull shots. In hindsight maybe I shouldn't have open it up to descale...

Thoughts on what else to check?
Last edited by Tuk123 on Fri Aug 24, 2018 1:36 pm, edited 2 times in total.

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Re: Mini Vivaldi steam boiler overfill, please help.

Post by chas » Wed Aug 08, 2018 4:52 pm

Sounds like a malfunctioning water level sensor to me. Since it worked right before you started messing with other things in its general vicinity, perhaps you partially or completely unplugged the sensor. You might try first to unplug it and then plug it back it to see if that fixes things. Also, the sensor sticks down into the boiler through a Teflon sleeve. Sometimes the sensor rises up through that sleeve and needs to be pushed back down.

If neither of those things works, you probably need to order a replacement water level sensor.
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Re: Mini Vivaldi steam boiler overfill, please help.

Post by Tuk123 » Wed Aug 08, 2018 5:51 pm

Thanks for the feedback Chas.

The issue appears to be intermittent. I tried turning on the boiler earlier, it came up to temp and didn't overfill.

Just to confirm, is the sensor you're referring to the one I circled in red? Is it this one? https://www.chriscoffee.com/Fill-Probe- ... p/8963.htm

None of the connectors are unplugged and I don't see any sensor sticking out. To be sure, I unplugged and plugged back in all the connectors.
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Re: Mini Vivaldi steam boiler overfill, please help.

Post by chas » Wed Aug 08, 2018 6:16 pm

yes and yes. Also I assume you are not using distilled or reverse osmosis water since that will not allow the water level sensor to work correctly.
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Re: Mini Vivaldi steam boiler overfill, please help.

Post by Tuk123 » Wed Aug 08, 2018 6:35 pm

No, I am not using distilled or reverse osmosis, just brita filtered.

I took out the water sensor and it looks clean. So it's a metal rod with an outer housing? Can you help me understand how the sensor can fail?

Stupid question, if I take out the probe from the housing, reconnect the wires to the probe and then stick it in a cup of water, will it still send the appropriate signal to stop the pump?

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Re: Mini Vivaldi steam boiler overfill, please help.

Post by chas » Wed Aug 08, 2018 9:00 pm

You're right. There's not much that can fail with the sensor itself. The problem is usually:

1) Bad electrical connection at either end of the wire (unplugged, loose, oxidized contacts, etc.)
2) Mineral deposits on the sensor
3) Sensor not pushed down all the way
4) Mineral content of water, too low.

The way the sensor works is that the entire body of the boiler is grounded. The Teflon shield around the water level sensor keeps it from being grounded. A small voltage is applied to the sensor. When the sensor touches the water, it conducts to the grounder boiler through the minerals in the water. The controller board detects this small current flow and shuts off the pump and solenoid.

Due to this mode of operation putting the sensor in a cup of water won't work.
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Re: Mini Vivaldi steam boiler overfill, please help.

Post by Tuk123 » Wed Aug 08, 2018 10:54 pm

As usual, thanks for the details Chas. I think we can eliminate #2, 3, 4 as potential culprits.

For #1, I tried tracing the connection but got lost in the cable jungle. I did notice lots of corrosion on the boiler ground wire. After cleaning as much as I could, the issue went away. Then again last time it went away by itself, so will see how it behaves the next few days...

If I do feel incline to trace connection, is there a easy way to take out the control board to make things easier?

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Re: Mini Vivaldi steam boiler overfill, please help.

Post by GDK » Thu Aug 09, 2018 10:13 am

I have put thermal insulation around and on top of the steam boiler, leaving only the steam valve exposed. As a side effect, steam and droplets which are always released as valve opens and closes never get to the electrical connections. The insulation material has temperature resistant plastic on the top side so that moisture does not soak in. I have had my mini for seven years and had to open it recently. I have no corrosion in that area at all. Just a suggestion.

BTW, an insulated steam boiler accelerated the ready time from 5 to 4 mins and then heating cycles less often than before.

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Re: Mini Vivaldi steam boiler overfill, please help.

Post by Tuk123 » Thu Aug 09, 2018 11:35 am

Funny that you mention this, I stumble on some old threads last night on boiler insulation. I was intrigued, but more from a lead time improvement and cutting down on cycles perspective. Few questions:
  1. What type of material to use? Preferably something that I can easily get from Home Depot.
  2. I tried to remove the boiler from the frame, but didn't want to force anything ... since I tend to do more harm when poking around. So I am almost embarrassed to ask this, but how do I take out the boiler?

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Re: Mini Vivaldi steam boiler overfill, please help. [RESOLVED]

Post by GDK » Thu Aug 16, 2018 8:23 pm

I used two type of insulation that is sold in small rolls at Home Depot. One is aluminum plated and I used it for the boilers, while the yellow one, can be safely placed on top of the steam with the pvc side up, but leave the valve exposed. No need to remove boilers. I hope the following pics help, I took them some time ago:
IMG_0001.JPG
IMG_0001.JPG (110.73 KiB) Viewed 1804 times
IMG_0003.JPG
IMG_0006.JPG
IMG_0007.JPG
There is some good links on this site on servicing the Mini: www.chriscoffee.com/

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Re: Mini Vivaldi steam boiler overfill, please help. [RESOLVED]

Post by Tuk123 » Wed Aug 22, 2018 11:29 pm

I found some aluminum insulation at home depot, will give it a shot. Thanks for the pics, they are most helpful.

Is there a reason why you used 2 types?
GDK wrote:
Thu Aug 16, 2018 8:23 pm
I used two type of insulation that is sold in small rolls at Home Depot. One is aluminum plated and I used it for the boilers, while the yellow one, can be safely placed on top of the steam with the pvc side up, but leave the valve exposed. No need to remove boilers. I hope the following pics help, I took them some time ago:

There is some good links on this site on servicing the Mini: www.chriscoffee.com/

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Re: Mini Vivaldi steam boiler overfill, please help. [RESOLVED]

Post by GDK » Thu Aug 23, 2018 10:28 am

Yeah. The aluminum plated bubble wrap like insulation seems to be more effective but could not use that on top of the steam boiler as there are exposed electrical connections there. Thus had to use non conducting insulation on top of the boiler.

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Re: Mini Vivaldi steam boiler overfill, please help. [RESOLVED]

Post by Tuk123 » Thu Aug 23, 2018 6:19 pm

Chas,

*Sigh* After 2 weeks of trouble free operations, my boiler overfilled again last night. The new fill probe came in so I took the opportunity to replace it. I also replaced the vacuum breaker as it was leaking, though I am doubtful that will help anything. Anyway boiler overfilled couple more times before the issue went away. So far it's holding up, but it had only been a day...

Question:

1. When initially removing the water probe, I inadvertently damaged the teflon sleeve. Examining more closely, sensor was sitting in at an angle, so it's possible it came in contact with either the nut or the boiler. Based on your description of how the sensor work, wouldn't the opposite occur? specifically grounded sensor sending signal to controller that boiler is full.

2. Also given issue is intermittent, is it possible the controller or triac being flaky?

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Re: Mini Vivaldi steam boiler overfill, please help. [RESOLVED]

Post by Tuk123 » Thu Aug 23, 2018 6:22 pm

This is the aluminum insulation I found: https://www.homedepot.ca/en/home/p.16-i ... 67785.html

Can you let me know where I can find the non conducting insulation?
GDK wrote:
Thu Aug 23, 2018 10:28 am
Yeah. The aluminum plated bubble wrap like insulation seems to be more effective but could not use that on top of the steam boiler as there are exposed electrical connections there. Thus had to use non conducting insulation on top of the boiler.

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Re: Mini Vivaldi steam boiler overfill, please help. [RESOLVED]

Post by GDK » Thu Aug 23, 2018 7:41 pm

I found them both for you and the good news is total is under $20:

Aluminum: www.homedepot.ca/en/home/p.pipe-wrap-4- ... 67780.html
Glass Fiber: www.homedepot.ca/en/home/p.glass-fiber- ... 18631.html

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Re: Mini Vivaldi steam boiler overfill, please help. [RESOLVED]

Post by Tuk123 » Fri Aug 24, 2018 1:35 pm

Awesome, appreciate the legwork and links. I like yours better.
GDK wrote:
Thu Aug 23, 2018 7:41 pm
I found them both for you and the good news is total is under $20:

Aluminum: www.homedepot.ca/en/home/p.pipe-wrap-4- ... 67780.html
Glass Fiber: www.homedepot.ca/en/home/p.glass-fiber- ... 18631.html

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Re: Mini Vivaldi steam boiler overfill, please help. [ISSUE REOPEN]

Post by Tuk123 » Fri Aug 24, 2018 1:44 pm

I am reopening this as issue came back this morning. The pump continue to run and boiler overfilled with water coming out of the safety valve.

To recap:

1. Replace pump and descale steam boiler
2. Boiler overfilled upon turning on the machine
3. Replaced water level sensor
4. Replaced vacuum breaker
5. Cleaned and double check all the electrical connection
6. Issue remains, though it's intermittent

To rule out the new pump, I am going to connect the old one back. Greatly appreciate it if there are any suggestions on what else to check?

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Re: Mini Vivaldi steam boiler overfill, please help. [ISSUE REOPEN]

Post by chas » Fri Aug 24, 2018 1:48 pm

You aren't using distilled or RO water are you? Too low mineral content in the water will cause the water level sensor to not work properly.
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Re: Mini Vivaldi steam boiler overfill, please help. [ISSUE REOPEN]

Post by Tuk123 » Fri Aug 24, 2018 1:50 pm

Nope, not distilled or RO. I got this machine late Dec last year and had been using the same brita filtered water. I change the water filter recently but I doubt that should impact anything.

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Re: Mini Vivaldi steam boiler overfill, please help. [ISSUE REOPEN]

Post by Tuk123 » Sat Aug 25, 2018 10:59 pm

Not surprisingly, the old pump has the same issue. I also checked the fill solenoid, it looks clean.

I'm now lost as to what to try next. There aren't many stores around my area that service spaziale, most of the ones I called ask me to try things that I had already done. Though one did mention it might be the controller.

Given controller is rather expensive, is there anything I can do to prove/disprove that? A friend gave me a multimeter recently, but I know nothing about electronic. So need some(or lots of) guidance.

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Re: Mini Vivaldi steam boiler overfill, please help. [ISSUE REOPEN]

Post by chas » Sun Aug 26, 2018 9:12 am

I don't have any other recommendations. The controller board is the only thing left that you have not tried. However, if it is the controller board, you will be the only person in almost 15 years on this forum that has had their controller board fail. Of course, there is a first time for everything.

One more question though: Does it ever overflow while you're pulling a shot or only when you're not pulling a shot?
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Re: Mini Vivaldi steam boiler overfill, please help. [ISSUE REOPEN]

Post by Tuk123 » Sun Aug 26, 2018 10:23 am

After debugging for last few weeks, what I observed is the issue mostly occur at initial startup.

At startup regardless of water level, 95% of the times pump will engaged, pressure gauge start climbing, and overfill once it gets into the red zone.
The remainder 5%, pump will not engage at startup and everything works perfectly. I can steam and draw hot water. Once water level drop below sensor, pump engages and disengages as normal.

The group boiler is fine, I can pull shot. So normally if I hear the pump running and pressure climbing, I just turn off the steam boiler and only pull shots.

I took out the control board and there are 2 wires for the level control I believe(highlighted in red box). 1 to probe connector and the other to ground. I was able to observe continuity between the controller to probe connector and controller to ground using the multimeter, so connections are good.

Few questions:
  1. Instead of going through the level probe, can I just connect both the probe wire and ground together to the chassis? Will this close the circuit and signal to controller boiler is full?
  2. I notice in the diagram the pump should be grounded; however when I replaced mine, there were only 2 wires and neither are ground(highlighted in blue and green box). Should there be a third wire?
  3. Following #2, I unplugged and measure between the ground prong and the body of the pump. I noticed a very small reading, is this normal?
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Re: Mini Vivaldi steam boiler overfill, please help. [ISSUE REOPEN]

Post by chas » Tue Aug 28, 2018 8:14 am

I have no experience with a Mini. On the plumbed version, there are 8 bolts around the perimeter of the boiler lid that hold it on. Under one of those is a large ground wire that connects directly to the ground bolt at the rear left of the machine and also the smaller ground wire that is for the water level sensor.

Since the mini doesn't have those bolts and I can't see the connection in any posted photos I've found, where do these wires attach on your machine. It still sounds to me like the water level sensor does not have a good connection to the steam boiler which it must in order for the machine to work reliably. Both the boiler itself must be well grounded as well as the sensor's ground wire.
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Re: Mini Vivaldi steam boiler overfill, please help. [ISSUE REOPEN]

Post by Tuk123 » Wed Aug 29, 2018 10:53 am

Yes, Mine has the 2 wires that you speak of.

The sensor ground is the white wire circled in blue.
The boiler ground is the larger green wire circled in orange. The screw also holds the boiler to the frame.

Yeah, I am still not convinced it's controller as this started after descaling. Thinking back on what you said on how sensor works, I decided to measure the delta in resistance on sensor when boiler empty vs full. When empty, it's coming back 0L which I assume is expected. When full, I do notice resistance but it fluctuates, ranging from 0.5 to 3mΩ. Do you know if the measurement is inline with expectation?

A new development, in the process of draining the boiler I notice some black debris. Based on what I read online, these might be metal shaving as a result of descaling? It's odd that I am seeing it now as I had flushed the boiler few times previously. I was in a rush to leave home but did manage to flushed the boiler couple of times. Judging from the amount of debris I will need to flush many more times. I will do that tonight and then fire it up to see if it improves anything.

PS: I am trying very hard not to be the first with faulty controller...
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Boiler Ground 1.jpg

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Re: Mini Vivaldi steam boiler overfill, please help. [ISSUE REOPEN]

Post by Tuk123 » Thu Aug 30, 2018 11:25 am

Some good and not so good news. The not so good news is it's not 100% fixed as I can still reproduce it. The good news is it's no longer intermittent and there is a workaround.

So I flushed the boiler again and again last night, must have been over 15 times. Here's the latest observation:
  1. Overfill if from cold start. (i.e. if group boiler is cold and I turn on steam boiler, pump will continue to run and overfill)
  2. If brew boiler is warm or hot and I turn on the boiler, then pump does not engage and it operates normally.
In all instances, the water level did not change. Workaround is wait till the group heats up before turning on boiler. For it not to overfill, the group doesn't need to hit the set temp, just as long as it's not cold. I was able to reproduce it on multiple times.

I am going to take some measurements on cold vs hot.

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Re: Mini Vivaldi steam boiler overfill, please help. [ISSUE REOPEN]

Post by chas » Thu Aug 30, 2018 2:58 pm

More questions about the Mini since I don't own one....

1) The first photo shows the ground wire from the water level probe bolted to the side chassis frame.
2) The second photo shows the main large ground wire bolted to the chassis on the front off the frame.

Where does that bolt in the second photo go on the other side of the frame; i.e. does it just butt up against the frame or is the other end welded to the boiler?

Assuming that the bolt is connected to the boiler. then things should work right in that the boiler would be connected to ground and so would the water level sensor ground by virtue of its connection to the chassis. However, the water level sensor ground and the boiler ground wire connections are some distance apart and depend on an excellent connection from both wires, through their lug and bolt connections, and finally through the chassis. It's possible that something is not making a good connection unless the heat from the brew boiler makes things by the steam boiler expand slightly.

What you might want to try is temporarily running a wire between the bolts circled in your two photos. Then you would have an actual wire connection to depend on rather than depending on a connection through the chassis.
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Re: Mini Vivaldi steam boiler overfill, please help. [ISSUE REOPEN]

Post by Tuk123 » Thu Aug 30, 2018 3:26 pm

The bolt should be to the boiler but I will check when I get home.

Instead of running another wire, can I just move the water level ground wire so that it's connect to the same bolt as the boiler ground?

Can I ask for your thoughts on my new observation? Specifically overfill if only from cold start.

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Re: Mini Vivaldi steam boiler overfill, please help. [ISSUE REOPEN]

Post by chas » Thu Aug 30, 2018 5:02 pm

Tuk123 wrote:
Thu Aug 30, 2018 3:26 pm
The bolt should be to the boiler but I will check when I get home.

Instead of running another wire, can I just move the water level ground wire so that it's connect to the same bolt as the boiler ground?
I was thinking my way would be easier as a test before moving the wire. However, now that I look more closely at your photos, I think moving the wire would be just as fast, so go for it.
Tuk123 wrote:
Thu Aug 30, 2018 3:26 pm
Can I ask for your thoughts on my new observation? Specifically overfill if only from cold start.
See last sentence in next to last paragraph of my previous post.
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Re: Mini Vivaldi steam boiler overfill, please help. [ISSUE REOPEN]

Post by Tuk123 » Fri Aug 31, 2018 12:22 pm

Chas,
Before I dive into my latest findings, I just want to thank you for your continuous effort in helping me debug this, you're a true gentleman.

So I moved the wire as suggested, but unfortunately no luck. I checked and there is continuity between boiler and ground.

It's a little frustrating as observations from one day may not necessary carry over to the next. I was able to reproduce the issue with both boilers hot, so it would appear my previous statement of this occurring only from cold start is NOT 100% true. :(

I took resistance measurements with machine on standby. The measurements were taken on the probe tip and ground wire. The wires are connected to the controller and the boiler is full and cold.
  1. 6.3mΩ - Overfill
  2. 2.7mΩ - No Issue
  3. 2.1mΩ - No Issue
  4. 6.6mΩ - Overfill
  5. 7.6mΩ - Overfill
Observations:
  1. Resistance seems to fluctuate. Numbers above are highest observed
  2. Black(COM) lead on ground. Red on probe tip
  3. Not sure how relevant, but in instances that boiler overfill I was getting negative resistance. It didn't really make sense to me. Anyway I ended up swapping and have black on probe tip and red on ground.
  4. To my point about issue only occurring from cold start. I was able to workaround the overfill except for #5. In that instance, I couldn't make it go over even after group boiler was up to temp.
Is something from the controller causing negative resistance? I am going to try disconnecting the wires from the controller and just measure the resistance between boiler and probe tip.

Also I am not sure why the resistance would spike given the water level didn't change. Could it be that there are still scale in boiler?

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Re: Mini Vivaldi steam boiler overfill, please help. [ISSUE REOPEN]

Post by chas » Fri Aug 31, 2018 3:56 pm

Negative resistance is not possible. I assume you are taking all your ohm readings with the machine off and unplugged. Otherwise all bets are off.

Have you tried filling the tank with tap water instead of running it through the Brita filter? Both the S1 Dream and my GS/3 have water level probe sensitivity adjustments for cases where the water is less conductive than normal. However, the S2 Mini doesn't, so you just have to count on there being a reasonable level of minerals in the water.
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Re: Mini Vivaldi steam boiler overfill, please help. [ISSUE REOPEN]

Post by Tuk123 » Mon Sep 10, 2018 9:38 am

I was away on business hence lack of status update.

Since the issue started, I had been using tap water just to eliminate another variable. My tap water is considered hard at ~130 mg/l.

Yes negative resistance, measured with machine unplugged. If I reverse the lead, I get the same number but positive(I know there is no such thing as negative resistance...). Any significance with it being negative?
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Re: Mini Vivaldi steam boiler overfill, please help. [ISSUE REOPEN]

Post by GDK » Mon Sep 17, 2018 9:57 am

Can you switch to voltmeter to see if any voltage is registered between the same two points?

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Re: Mini Vivaldi steam boiler overfill, please help. [ISSUE REOPEN]

Post by chas » Mon Sep 17, 2018 11:01 am

That shouldn't be a problem since the power cord was unplugged before measuring. However, the measurement does need to be made with the wire to the water level sensor disconnected. These days all semi-conductor inputs include a protection diode to prevent an external voltage from blowing out the input.

Resistance measurement devices use a small internal battery to supply a voltage used to determine the resistance. So if the sensor is left connected, the input protection diode on the device that connects to the water level sensor is getting turned on resulting in an incorrect reading.
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