Finding water in Mars has better chances indeed.
I need 3 of them which means 350$ Real SSR instead of 34$ (fake) Fotek.
There have been instances of recall where known SSR manufacturers been falty so, the risks are always present weather its cheap or not.... but it does open the door for extensive tests and considering the expensive option, many times, the expensive option is the "cheapest"...
230v AC
So, less than 4A.
I know. What's wrong with "normal" relays for your setup?
Typo....sorry
I need 3 relais for my setup. 3 relays = 3 * 50$ = 150$
or 3 relays FOTEK 3 * 4$ = 12-15$
I got it.
But why not common 4-ch relay module?
I did checked those, it would be for me preferable, but as i said, 3 boilers having 3 relay modules that go clickety-clack multiple times a minute....im gonna need to soundproofing them 
Correct, that is why i chose the 25 A and not the 10A relays. Even if they are fake or not as advertised or what ever, i would still have a big margin....thats the idea.
I have ~50 relays in my house and I have never been disturbed from them. I also have two espresso machines that wake a person even from death when operating. Up to you.
lol now i have to at least try them. I have bad experience with normal relays switching on and off making sounds...thats why i wanted SSR. But i will give it a try.
If you locate them well, you barely hear them.
I'm not generally against of experimenting cheap components from chinese online stores, but if I want to sleep well, I prefer relay clicks. I read a long post a while ago from a guy who got the whole house burnt down to earth with fake fotek fail. I personally have one genuine Fotek running for 8 years without any problems though.
Actually both are wrong.
I'm sure that the connections suggested by Seeed is not what you show.
The AI version will not work the other will burn out the relay.
50$ relays? 4$ SSRs?
I wouldn't pay 50$ for a branded contactor.
800-W heater at 240-V AC. That's 3.3-A. Not a lot.
Spend a bit more on a decent SSR from a reputable supplier, RS, Farnell, Digikey etc.
I had a neighbour with PV solar panels on a semi-detached house.
The invertor in the loft failed, started a fire, burnt out the entire roof and first floor, including his neighbour's roof.
Took nearly a year to repair, under a scaffolding temporary roof. Not saying it was an SSR or a cheap invertor, but it sure was expensive. And scary.
Has nobody spotted that the polarity of the signal to the SSR is reversed?
The Seed MOSFET module uses a P Channel MOSFET.
When activated, the OUT pin becomes positive with respect to GND.
There is no need to connect the 5V supply to both J2 and J3.
Yes.
See post #33
@JohnLincoln n the original post, i wrote :
This is the Seeedstudio link where i got the info from.
Instead of a small DC motor, i have put the Fotek SSR.
Polatiry in SSR matters indeed on the contrary the DC motor doesnt matter as it is spinning both directions depending on the polarity. It was lazy on my part not to correct it.
Correctly pointed out by @JohnLincoln
and as i wrote in my original post
So i am confused into which info is correct and how would be the safest way to control the heating element.
Both are still wrong.
appreciate your responce Jim. Gonna have to read more in depth on this.
