Solar thermal - servicing / upgrades (Cork metropolitan area)

I retrofitted the SR208C Wifi controller from Aliexpress and have it connected to Home Assistant via Tuya. Only complaint is the SR208C controller doesn't leave a lot of room for the sensor cables coming in, so it's difficult to get the sensor cables in neatly. Still playing with the interface - need to tidy it up a bit.

Cool - let me know if I can be of any help. Straight forward enough though. One thing to double check is the type of temperature sensor you currently have on your system. I had to swap one NTC on the panels themselves for a PT1000. Even easier if I didn't have to do that.

I have a collector probe all right, any idea how to tell if it's a PT1000 or an NTC without taking roof apart or crawling through attics?

It's often written on the wires, or you can read the temperature, disconnect the sensor really quick and read the resistance across it with a multimeter and compare that to NTC / PT1000 graphs. Alternatively, a quick google of the Kingspan sc100 suggests it only takes PT1000s.

ESP will be my next learning adventure :) It's not something I've sat down with yet.

I can have a look and see if there's anything obvious when I get home later in the week. I do have it local though!

Connected to home assistant via the Local Tuya integration. A bit of a balls to set up, but runs grand with no cloud dependency.

@graememk @randombar apologies I got that wrong/missremembered. The SR208C does indeed come with 2 NTC and one PT1000. I just remembered I actually had to swap all three sensors. It needs PT1000 in the collectors and 2 NTC for the cylinder. So you will have to swap the cylinder probes on the Kingspan controller (but thankfully not the collector probes).

I got confused because my original solar controller was the inverse (NTC in the collector and PT1000s in the cylinder - twas unfortunate!).

Nice work!

I did configure everything manually in localtuya - I'll have a poke around for a config file and get back to you on that one.

Regarding T3, see the menu structure manual screenshot below. You need to change SMAX from the default of S2 (T2) to S3 (T3).

I did tweak the temperature parameters slightly (but the defaults are grand) mainly because I extended one of the sensors quite a lot so I had a little offset to account for on T1.

That's brilliant thanks.

Interesting about the temp parameters.

I'm not sure if the t1 is 100% accurate. I disconnected the old controller and I'm sure it said 70 and connected the new controller (1 hr later) and I think it said 46 or so.

I don't actually know 100% as the sensor is wired gold only knows where in the roof.

The manual or settings in the old controller might tell you. What controller did you have in before?

The SC100 (A classic at this stage). I think it's a PT1000 all right.

It might just be a case that there was a temp drop in the hour I was working on it, it was evening etc. 24 degrees now and probably won't get much higher today I'd say.