Why UFH?

[joe90]

7 minutes ago, Pete said:

LOL, should have known, sorry will sit in the naughty corner with @AnonymousBosch

 

It’s just that I am a Luddite, I understand electrics, electro mechanicals (relays etc) but not electronics. I like woodwork and driving my 68 year old tractor ?. An interesting part of @JSHarris blog was a complicated, weather predicting means of controlling his heating that he designed (clever bloke eh) but he found a simple room stat worked better. I am not saying that all complicated stuff is unnecessary but I prefer a simple solution (that I might have a chance of understanding).

[SteamyTea]

1 hour ago, joe90 said:

I am not saying that all complicated stuff is unnecessary but I prefer a simple solution

It is really do do with the user interface, not what goes on behind the scenes.

My car is in for the MOT at the moment, been lent a Toyota, even though things are different, I can still work it.  Shame the IT industry does not take the same approach.

 

[TerryE]

6 hours ago, Nickfromwales said:

Just a heads up on how a simple man like myself would switch one of these on / off from a 230v signal would help. I assume the 230v would fire the coil in a zero volt relay and I'd have to generate the 5v from an 3rd party adaptor / transformer and send that through the zero-volt side of the relay?  Simple on / off operation will suffice, mainly because I try and set things up so some poor fool would be able to reasonably quickly identify what's been done and how it works ( in the event of a breakdown and I'm not of this world anymore ) for fault-finding / ongoing maintenance & repair by A.N. Other.

 

This would be better as a boffins topic and I apologise @Robert Clark for the digression on your thread, but such is the Buildhub way ?.

 

For others, the main point is that you need the correct device for switching power circuits.  You can buy remote switches and cheap relay from eBay and various suppliers and there are three points that you need to ask:

• Is the device correctly rated for 240V?
• What is the maximum peak power rating?
• What is the maximum sustained power rating?

If you want to drive a Willis or a SunAmp then you need a switching device that will support a 240V 12A load for multiple hours on a duty cycle of up to 1,000 cycles per year minimum, and as @ProDave suggested in one post it makes sense to have a little safety margin so having device rated at 240V (not 220) 16A and 50Hz and supplied by a reputable OEM is sensible.

 

As @dpmillercorrectly points out you can get these with  "zero V" inputs as well.  Typical prices are in the £45 ballpark for the SSRs which have a decent heat sink and DIN mount or £35 for the ones designed to be directly attached to the steel plate of the cabinet and use it as the heatsink.  (SSRs are only about 99% efficient, so they typically give off perhaps 20-30W when switching a 3kW load.  That's enough to hatch chicken eggs.   Though another option for zero volt input is to use a decent contactor which only give off maybe 5W from the energised coil.

 

 

 

[Nickfromwales]

18 hours ago, TerryE said:

Though another option for zero volt input is to use a decent contactor which only give off maybe 5W from the energised coil.

 

Too clunky and noisy to have inboard on a TF house though, hence me chasing solid state.

[TerryE]

See

 

and as I said you can get zero-volt input SSRs in both panel mount and DIN rail mount configurations.  Dumping the 30+W can be a PITA to manage.