HX Autofill: Erratic behavior - flickering

Equipment doesn't work? Troubleshooting? If you're handy, members can help.

Postby Yacomonti » Mar 08, 2019, 7:11 pm

Hello to all,
Like always, thanks to everyone for such invaluable knowledge that this forum shares, and sorry for my English.

I'm having an annoying and erratic behavior with water autofill; was searching and reading the forum info for a couple of days but can't find a similar case.

Here a little info of the symptom:
Is a Hx machine controlled by a box through a level probe.

The autofill activates erratically always, turning on and off very fast, each 1 second the machine tries to refill, like the probe was reading water ground erratically.
At this exact moment if I ground the probe cable to the boiler the autofill stops, assuming the control box is ok.

Some considerations:
-The level probe is brand new, so there is any Teflon crack
-The control box components seems ok (reading with multimeter)
-The boiler was descaled through boiler purge nut.
-The solenoids are activating ok
-Im using hard water
-The connection and cables for probe and box are new

Got stuck :shock: ; I will really appreciate any thoughts regarding what can I analyze and test for this behavior.


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Postby Jake_G » Mar 09, 2019, 11:37 am


Sorry you're having troubles with your machine! I see you have a couple vintage Pavonis listed on your profile, what HX machine are you now using? While I haven't come across this exact issue before. I have seen a few others that are similar and this one comes to mind: Laurentis rapid pump cycling on startup

Since the auto-fill works correctly when your machine is cold, and grounding the level probe wire stops the erratic call for water when it is hot, I am inclined to look towards one of the capacitors on the brain box, but this is really not my area of expertise. User Jpboyt is our resident gicar/giemme control box guru. He repairs them for a nominal fee, but frequently offers advice to folks who would rather do the work themselves, or live in Argentina :wink: His website is below: https://boytenterprises.com/collections/electronics

I would suggest sending Pat an email or PM as he really is the best resource out there to get you running again if the issue is in the control box. Please let us know how it turns out.


- Jake


Postby Yacomonti » Mar 10, 2019, 12:18 am

Hi Jake!!
The machine is from an argentinian brand:


Thank you very much for such dedicated comment and help, i will inspect that thread and send an email to Pat while i continue the analysis.



Postby Yacomonti » Mar 13, 2019, 12:25 pm

I had an update, a poor update really.
I know the inconsistency is the level probe sensing the boiler water, no matter if is hot o cold.
The probe is brand new and re-desescaled the boiler, and if I touch the boiler with the cable refill on and off works just fine. Y change the terminals of the wire and the wire too.
The steel probe is 20% free and 80% recovered by Teflon, so only 20% is in contact in the boiler ambient.

Someone know what test I can do to meassure the the resistance with a multimeter, what impedance should have between the probe and the cable or the controller while is making ground with water.



Postby Nunas » Mar 13, 2019, 12:36 pm

I've been watching this thread with interest...very strange problem! Alas, I can think of nothing to suggest. As for your latest question,
Someone know what test I can do to meassure the the resistance with a multimeter, what impedance should have between the probe and the cable or the controller while is making ground with water.

I think this will not help you. The value of the resistance set up by the probe touching the water will depend on the nature of the water. This is why manufacturers often state not to use distilled water or RO water with low TDS.

If I had to take a wild guess, I'd be looking for a ground problem. I hope you find the problem...and let us know what it was!

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Postby civ » Mar 13, 2019, 1:00 pm

Yacomonti wrote:... the autofill activates erratically, turning on and off very fast, each 1 second the machine tries to refill ...

Since it works when cold and behaves erratically when hot, it could be that you are having a mains water pressure issue.

You need at least 1.5 bar water pressure for autofill to work properly.



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Postby Jake_G » Mar 13, 2019, 2:54 pm

Yacomonti wrote:The probe is brand new and re-desescaled the boiler, and if I touch the boiler with the cable refill on and off works just fine.

This is mighty frustrating...

What happens if you try the following?

•Push the level probe down a bit to lower the water level (careful not to expose the heating element!), drain some water out and then let it top up the boiler cold.

•Warm up the machine, power it down and carefully raise the level probe up as much as you dare.

•Turn it back on and observe the behavior.

If it pumps irregularly from the start, you very likely have an issue with the insulating sleeve between the probe and the boiler, which is causing the ground to not be fully interrupted when the water level falls. Solution? Replace the insulating sleeve.

If it pumps just fine until the water level reaches the probe and then it starts acting up, the water is not making a solid connection with the ground through the boiler. Check to ensure that you have a very good bonding wire between the boiler itself and the machine ground. Particularly, the ground terminal that the gicar controller is referencing should be connected to the same lug that the boiler ground wire is connected to.

Please try this test and report back.


- Jake


Postby Yacomonti » Mar 13, 2019, 5:42 pm

Excellent guidelines guys many thanks to all for the time for the recommendations and appreciations.
Too bad i can't measure resistance..its true that it will depend on the water and the system, and i dont have any working parameter for comparision :(

I'm desperate to get home to start this tests :)

I will report back soon.

Thanks again!


Postby Yacomonti » Mar 13, 2019, 11:58 pm

Ok, i did some tests and I am so much lost than before jaja.

Follow the recommendations, the erratic behavior happens from a cold start with low water in the boiler..so the premises are:

1_It fails from a cold start
2_Clear continuity between boiler and Ground. (Ok)
3_No continuity between level Cable and probe to boiler or ground. (Ok)

Test 1.
Disconnect from Control Box the 2 output hots, they came from relays activating motor and selenoids.
Result: The relay activating ok and steady with no erratic behavior (no flickering on and off)
So water level is working ok and control box too.

Test 2.
Connect the output hot going to Motor and Selenoid in the control Box and disconnect the output water Pipe directly from the motor to bypass the selenoid.
Result: The relays activating ok and the water flowing to a reservoir.
Ok, motor works ok, let's see the selenoid.

Test 3.
I connect the output motor water pipe to selenoid.
Result: erratic behavior with relay and motor flickering on and off.
...Well is the selenoid.

Test 4.
Turn machine one, flickering starts, disconnect cable from level probe and... !!!flickering go off and the boiler fills awesome!!

This test blow my mind away.

Conclusions so far with this tests:
1_Level Prove ok, grounds ok
2_Motor Ok
3_Selenoid (ok when grounding cable probe with boiler, error when grounding probe with water??)
4_Control box ok(relays activating ok, flickering in closed system/normal machine operation)
5_Plumped Pressure water in line problem? It seems not, with all the circuit closed and grounding the cable to boiler it enters to boiler, so in water pressure ok.

I'm really lost, doubt is a joy given from god :D

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Postby Jake_G » Mar 14, 2019, 1:19 am

Yacomonti wrote:3_No continuity between level Cable and probe to boiler or ground. (Ok)

From the rest of your tests, this seems impossible. No continuity does not mean infinite resistance. I think you have leakage between the probe and the boiler that is mucking up the capacitive sense circuit in the controller.

How are you doing your tests? Raise the probe with the wire attached and see what the controller does? Does everything calm down when water actually touches the probe? Here's my troubleshooting process flow on this one:

•Does water touching probe shut off pump reliably?
-Yes: Probe is working correctly and boiler is grounded. Go to next question.
-No: Probe is not reading water, or boiler is not grounded. Fix probe or boiler

•Does removing the wire from the probe result in proper operation of the pump and solenoid?
-Yes: The controller, pump and solenoid are all working properly, go to next question.
-No: You got problems ;)

•Does lifting the probe out of the water result in proper filling of the boiler?
-Yes: The probe is isolated from the boiler and apparently your machine is working. Yay.
-No: The probe has leakage from the wire (which works when disconnected if you passed the above tests) through to the boiler ground when the probe is not touching the water. Insulating sleeve is not doing its job...

Does that thought process make sense?


- Jake