With both types I have experienced a strange (i find it strange at least!) behaviour:
If I keep the relays in a vertical position and I don’t activate them for an extended period of time, next time I try to activate them they will do nothing! The light on them switches to green so the connections are good but the relays don’t click and make a connection. When this happens and I am near them I can give them a small bump with my finger and then they will work again.
I have searched if there is a requirement for these types of relays to sit in a horizontal position but I couldn’t find anything related to this. Is this a known issue? I tend to believe it is because I have changed the relays and experienced the same behaviour. I was thinking of moving to solid state relays because they are more reliable and not dependent on orientation.
You’re not trying to switch them with 3.3V are you?
I have two Wemos relay shields like this:
…that use exactly the same model relay as in your two pics, mounted vertically (screw terminals at the bottom), running my central heating and hot water. They’ve worked flawlessly for over a year now, with the central heating relay coming on last autumn after several months of being off. Power comes from a Vigortronix VTX-214-005-105 module, providing a solid 5V supply to the relay and the controlling Wemos D1 Mini.
Sounds like you may have a borderline power supply, perhaps?
Another possibility: are you switching off a high-current inductive load? This can cause arcing that degrades the contacts, perhaps making them “sticky”.
i am switching a water valve for my sprinklers and I control it with an ESP8266 from nodemcu. right now I have no idea if I have connected the 3.3 or the 5V pin… I will check this evening this could be it.
