Mon, 25 May 2026 08:50:41 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18025&Focus=304292#Comment_304292 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18025&Focus=304292#Comment_304292 Fri, 17 Nov 2023 17:33:02 +0000 Charenteman
Can anyone advise on a set up problem with this controller ModvSol S ?
It should be a very basic S1 S2 temperature difference pumped operation between the panels sensor and solar pocket sensor.
The instruction Manual only illustrates various S1 S2 scenarios.
However when I turn the system on it illustrates S1 S2 and S3.
S1 shows nothing
The expected S1 reading is shown as S2 (48 degrees when I put the tubes in late this afternoon)
The expected S2 reading is shown as S3 (16 degrees at the solar coil area at the base of the cylinder)

The system is not running/pumping at all and I am very worried that the collectors are going to overheat if the sun returns tomorrow.

The pre wired box seems to be wired correctly.

Do these symptoms mean anything to anyone?!!

Thanks]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18025&Focus=304293#Comment_304293 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18025&Focus=304293#Comment_304293 Fri, 17 Nov 2023 18:24:11 +0000 philedge https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18025&Focus=304294#Comment_304294 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18025&Focus=304294#Comment_304294 Fri, 17 Nov 2023 18:27:44 +0000 philedge https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18025&Focus=304295#Comment_304295 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18025&Focus=304295#Comment_304295 Fri, 17 Nov 2023 18:46:06 +0000 Charenteman
Sorry - to clarify, the controller sits in a polystyrene slot in the pump station.
A sensor labeled S2 was already connected to this controller and a sensor twin wire labeled S1 was also already connected.
I have put the S2 sensor into the lower cylinder pocket and I have connected the S1 sensor cable to the wire running to the sensor in the collector panels pocket.
I took the back off the controller and the connections did seem to be right way round - I’ll have to take another look.
If they are, do you have any other thoughts?

Thanks for your help
Chris]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18025&Focus=304298#Comment_304298 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18025&Focus=304298#Comment_304298 Fri, 17 Nov 2023 19:14:36 +0000 Charenteman I rechecked the wiring order which was correct.
Scratched my head and then noticed that the pre fitted connector block was positioned one pin out….

Thanks for the prompt suggestions - much appreciated.
Can now sleep easy!!]]>