Thanks. The owner is going to find another relay, same part number this time, and see what happens
Will keep you all posted. Thanks...

Ok, we got a reply from the electrician, this is the relay he removed, it looks like he swapped the socket as well...
Eltako ER12-001-UC
So GPT states that this is NOT a SOlid State relay but it is electronically triggered (darlington inside?) so it takes really low power and also it says it works by pulses (toggle??) so it won't take current while ON...does it make sense?...

I think what you are seeing is the remain of flux from when I desoldered the header that drives the relay for the pellet feeder, right on top of the LF444, but I didn't touch that IC at all, and I am the only one who has touched this board. No, I don't think this IC has anything to do with this function, which seems to solely relay on the LM358, the LF444 is used for INPUTS, as it is wired to other headers for detectors.
Im still awaiting for the owner to get a picture of the original relay that the electricina removed

That IC is an LF444 (Quad OpAmp), I already checked it before, it has some inputs connected to some other headers (I guess sensors) at the board, it seems like one track is connected to the same header (see scratched varnish) but I removed the header and this track goes across to another header on top if it. I checked and there's no electrical connection at all between this LF444 and the pellet feeder output header

Thanks...

No worries, maybe you misunderstood me. I was just asking what would be the "usual" device to have out of the board to be controlled directly by the output of an OpAmp in order to drive a 220v AC motor. Assuming the electrician didn't change the socket, I guess there would be a SS relay, but anyway my friend is going to find out soon when the technician sends a picture of the "relay" he took., I am 100% positive the board itself has not been altered my any means, but any component out of the board might...

Thanks!

No, I have the board, but the board is part of a large machine installed at the basement of this building. I only took the board. The relay socket (din rail mounted) along with other boards and modules were left in the machine, from which I took no photos... The owner is asking the electrician for the original relay PN or a photo...

I talked to the owner, he said the electrician left saying the relay wasn't working and he was going to find another relay, he took the original. Then he came back with a bunch of other relays and none worked. I bet there was a solid state relay and he tried to replace it with a mechanical relay? Does it make sense? Do you thing there are SS relays that match pinouts with classic mechanical relays to use their sme socket? Maybe he swapped the socket too. He's calling this electrician to ask for a photo of what he took

You mean the resistor between the OpAmp output and the header right? I can't get a valid measurement now as I got this board at my house (15 km from the original machine) and I can't force the output to HI, but if we find out the relay should not be a normal mechanical relay, I will be back there soon...

Thanks, the fact is that when I got there, there had been another guy, an electrical guy, who left some relays around there, of varied voltages like 6V and 9V, and left the place saying the issue must be at the board as none of the relays work... This makes me think, maybe he modified something in the circuit and what was in the relay socket was not a normal mechanical relay?

What could it be? An electronic relay? There was a rail mounted relay socket, that's all I found there...

Hi all!
A friend asked me to repair his biomass (pellet) heater. This heater has a pellet feeder powered by a relay that's not switching anymore

I measured the voltage at the relay coil socket while entering the individual tests procedures and it has 6-7v while the relay is NOT on the socket, and drops to 0v when the relay is plugged in the socket, like the source is providing nearly 0 mA. I measured the relay coil and it is correct and not shorted so the issue is in the board, fed no amps to this output

I checked the board at home and this output is driven by an...