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

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Tuk123
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Mini Vivaldi steam boiler overfill, please help. [RESOLVED]

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?

UPDATE: It looks like corrosion around the ground was the issue. It had been almost a week since boiler last overfilled. Thanks Chas for all the help and insight, much appreciated.
Last edited by Tuk123 on Mon Aug 13, 2018 12:10 am, edited 1 time in total.

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chas
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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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Tuk123
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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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chas
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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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Tuk123
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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.

Tuk123
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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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