I have an AV gs/3 that's about 10 years old, gets used daily, and turned off at night. For the past month, I've been having some really strange things occur. It first started with getting a steam boiler overheat error message on the screen. I tested the steam heating element and it was fine but noticed the screw terminals were crusty. Then the circuit breaker main on off switch started to blow and get really hot. So I cleaned up the terminals with some contact cleaner and put it all back together. So far, so good.

After about two weeks of working good, now I have another problem. The pump automagically turns on and stays on. I looked at the auto-fill sensor and took it out but it wasn't crusty. I just ran a paper towel over it anyways. Put everything back together and it still happens but not all the time. When things are working properly, I take the wire off the auto-fill level sensor probe and the pump turns on. Put the wire back on and it turns off...as expected.

I have my pump and motor outboarded because the machine would jiggle the cups around when on. The strange thing is that when the pump and motor turn on automatically, I don't hear any clicking on the right side of the machine, behind the tea water spout. Normally, when the machine fills the boilers, you hear a click and then water running into the boiler. But when I have the problem, there's no click and there's no rush of water in the boiler.

I'm starting to think that it may be the fill solenoid that may be going out. I was wondering how I could test it to see if it's the solenoid/coil or something else. I started experimenting and it looks like when things are normally working, I get about 190 ohms across the terminals and see 120v being delivered to the solenoid. I haven't tested it yet when the pump is running and the situation where the machine is broke.

Am I doing it right? Should there be 190 ohms across the coil and 120v being delivered? Does it matter if I test the coil with the wires connected or not? Thanks in advanced!

After I post, I usually figure things out. I went back to the machine to test across the coils when it was powered down and the wires off. I was getting an "OL" (open loop) on my multimeter. I checked the reading across the other two solenoids and I was getting, maybe something around 190s to 200 ohms at my 1k setting.

Since I was getting an open reading on the coil I think it bad and a closed reading on the other two coils, I'm guessing my coil may be bad. Still seeking confirmation though as I'm still new to testing these and could just use a verification.

Sounds reasonable. I'd check isolation to ground as well.

Don't know if 190 ohm is good - but it rarely fails by changing resistance. It is usually a fail open device (infinite ohms).

When machines act up I suspect water in the brain box. Turn it off, dismantle the rear box and look inside. Water is usually held by capillary action between the PCB and the box itself.

If so, dry it. Also my recommendation is to drill a hole grate in the bottom of the box. And if you know how, conformally coat the board.

Thanks for the response. I popped the box open and there are no signs of water in the box, even dried up water. I called LM last week and they said to take the PCB out and check the back of the board too. I'm a bit lazy as the machine is tucked away and plumbed in so taking the board out would be complicated.

Now I'm thinking that it may be the coil. I tested it a bit more and it seems like when it gets hot it fails. I had a solenoid behind the group head fail when the machine warmed up because of the heat/cool expansion. If I take all the covers off it seems to work fine. Put the covers on and then it fails.

When it did fail a few minutes ago, I tested and did see voltage going to the solenoid, but there was no clicking on that solenoid. I was still seeing 'ol' when testing the solenoid so I'm thinking that might be what it is. I'll call LM on Monday just to verify but I think that's it.