hosseinzr:
The device is 120V AC 12A which is above relay board safe range. What can I do to avert the problem for the a new channel?
The site from canada is saying 250V AC 10A. It will be interesting to see what amount of current is actually being drawn on average. And if you have spare modules...... which we should have... then try out the replacement module. And if possible.... do some measurements of the current.
Southpark:
The site from canada is saying 250V AC 10A. It will be interesting to see what amount of current is actually being drawn on average. And if you have spare modules...... which we should have... then try out the replacement module. And if possible.... do some measurements of the current.
Multimeter shows up to 3amps on relay when it's connected! But it's a bit hot.
So still solid state relay?
A 5volt sugarcube relay coil draws about 75mA.
That's 5*0.075= 0.375watt generated in the coil.
That will make the relay warm, which is normal.
If you put that relay inside an enclosure, it might even get 'hot'.
But 'hot' is a relevant term, so what do YOU think is 'hot'.
A SSR (already mentioned that in post#6) could fix that 12Amp current issue, if you oversize (20-30Amp).
A SSR also gets hot. Not from the coil (doesn't have one), but from the losses in the triac.
It might need a small heatsink.
Leo..
Hi,
Welcome to the forum.
Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html then look down to item #7 about how to post your code.
It will be formatted in a scrolling window that makes it easier to read.
Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?
Thanks.. Tom... 
I just had to mention it is incredibly hot as you cannot keep your finger on it longer than 3s (thermometer shows well under 85C). The setup is still exposed to open area though. I've already lost one channel of this relay board and don't want to lose another one for the same reason.
Available SSR comes with this information:
Rated output load: 2A at 100 to 240VAC. (50/60Hz)
Is it still fine for 12 amps?
hosseinzr:
Available SSR comes with this information:
Rated output load: 2A at 100 to 240VAC. (50/60Hz)
Is it still fine for 12 amps?
A rating value just means .... don't go above that value. So if it says 2A output ... then it basically means ... don't make the device operate above that level of current.
hosseinzr:
Rated output load: 2A
Is it still fine for 12 amps?
Ofcourse not.
Google "solid state relay", and look at the images.
The square blocks that you can screw to a heatsink are rated for ~25Amp.
Leo..
OP ..... so ...do you have 1 or 2 spare relays of the same kind..... for testing? Replace the one you have with a different one of the same kind. And then see what happens.
Also..... use your multimeter to measure the DC voltage applied to the relay..... to see what actual voltage it is. And measure the coil resistance of the relay as well.
TomGeorge:
Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?
All of the items controlling by arduino or just the AC device? Asking this as there are lots of other stuffs managed by arduino and prepare a complete drawing is not so easyLol
Here is you drawing, use 500 ohm resistor instead 100
https://www.google.ca/search?q=led+in+parallel+with+coil&rlz=1C1AFAB_enCA475&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiVlJPLsMLaAhVK74MKHUZdB8sQ_AUICigB&biw=1440&bih=787#imgrc=hKW3FVtcdNEdPM:
Post the picture of the back PCB.
Measure voltage on pin Vcc
hosseinzr:
Multimeter shows up to 3amps on relay when it's connected! But it's a bit hot.
This is your problem, wrong connection, normally relay can be turn on for days and will not get hot.
Don't put the load on relay and tell me it's still hot ?
hosseinzr:
All of the items controlling by arduino or just the AC device? Asking this as there are lots of other stuffs managed by arduino and prepare a complete drawing is not so easyLol
Always, always, always, make a schematic for your projects.
Oh, and when asking for help, show your wiring.
Not really wise to argue with the people who are trying to help you. 
Southpark:
OP ..... so ...do you have 1 or 2 spare relays of the same kind..... for testing? Replace the one you have with a different one of the same kind. And then see what happens.
Now I connected the device to another channel of the same board. It's fine now. Not sure what happens in the long run though!
hosseinzr:
Multimeter shows up to 3amps on relay when it's connected!It is the current taken by relay coil ?
Normally relay is using current in range 20- 50 mA.
ted:
hosseinzr:
Multimeter shows up to 3amps on relay when it's connected!It is the current taken by relay coil ?
Normally relay is using current in range 20- 50 mA.This is the current when you put one lead on NO and the other on COM of the relay channel.
That's right. Measure the input side .... ie. measured coil current, and "measured" voltage applied to the input side. And measure output current --- but be careful with mains power measurements.
Hi,
Can you post some pictrures of your project please, so we can see your component layout.
Have you got a fuse in the mains power circuit?
Thanks.. Tom...
No. According to my calculations, 2A is less than 12A.
hosseinzr:
Now I connected the device to another channel of the same board. It's fine now. Not sure what happens in the long run though!
Does this mean that the relay on this particular different channel is very much cooler than the previous channel used? In other words...... not as hot?
Attached is the prepared sketch for the setup. Hope I did not forgot anything there:)
Please note that I used a 1602 SainSmart LCD with button which provides connections from Arduino. That's why you don't see wiring to arduino in this sketch. In addition, for some reason the LCD part in fritzing has less ports like 5V.
I could not find fritzing part for some items like humidifier, so I skipped those as they work fine.
The problem is just for the item in the bottom called Water Bath.
Currently, the whole setup works quite excellent. As this device is being switched off every now and then the relay has time to cool down. I'm just worried about long runs.
Thank you all!
