Solar panels not working - older tubular system

Dotdom

HI I am looking for some help with the attached system which stopped working over a week ago. We have been unable to contact anyone who can help, any feedback would be appreciated 😊

John.G

Check that the (solar) system pressure is around 2bar, it shoul be near the expansion vessel and the solar circ pump.

Dotdom

Hi JohnG, would thus be it? Sorry I've no clue 🫣

John.G

Yes thats it, it seems to be reading (top pressure gauge) 0.8bar which should be just about enough, have a look at the attachment to read off the various temperatures, and write them down, if the COL (collector) temperature is still reading > than say 70C then the pump (Wilo) should be running now, just feel it.

You should be able to take the cover off the "pump station" pump+pressure gauges and you might see a sight glass somewhere around there which is a flow meter where a little bobbin moves up when the pump is on, there could also be air in the evacuated tubes which will stop circulation, anyhow have a scroll through all this, the + and - buttons should just display different schematics & temperatures maybe if you just press them.

Resol DeltaSol.pdf

Dotdom

COL much higher now but don't see a sight glass, thanks so much for helping 😀

John.G

Did you scroll through the displays by pressing the arrows.?, the pump won,t be running now anyway. Its inhibited at very high collector temperatures.

I will have a look later at the instructions to see if you can test the pump manually.

Can you use a Multimeter?.

Dotdom

Can't see a multi meter and when I use the plus minus thus is what I am seeing 🫣🤔

John.G

I mean do you have a multimeter which is used to test circuits for voltage and resistance, looks like you havn't but no matter, if you know someone who has, and can use it, get them, (with the panel powered up) to check for 230V between terminals 20&17, if so, get a piece of insulated wire and link terminals 20&18 for a few seconds and stand at the pump to see/hear if it starts. That TST (S2) (store) reading of 17.7C is the temperature of the water just above the solar heating coil and if the collector temperature COL (S3) is 6C or greater than TST then the pump should start and continue to run until the temperature difference reduces to 4C, the pump then stops, these temperature differences can be changed but I doubt if they have and are left at these default settings (I have mine, different controller, set to 7C and 3.2C), its as simple as that. Suggest first step anyway is to check that the circ pump will run.

Dotdom

Thanks so so much, I will speak to the electrician again when I am back week after next. I will definitely let you know. You have given me more information today than I got from everyone else put together 😀