new house with Solar Heating question

We have moved into a house with a solar heating array on one of it's roofs.
We were told it was operating and certainly the Suntanna 2 controller shows switches working and temperatures in the collector and storage tank going up and down with daylight.
System has a pressure gauge which is currently at 4 bar.

There is a worcester greenstarHE combi, run off an LPG tank.
Not quite sure if this is cold water fed or not, i.e. it maybe fed off the solar tank (which would make alot of sense).

When we turn on a hot water tap the water runs cold until the combi kicks in. I cannot seem to make the temperature in the solar storage tank drop by running taps - surely at night, when the collector temp is way lower then I should theoreticaly be able to drain it until it runs cold ?

The boiler shows the water temp on it's little LED and that currently reads 42, which is slightly more than the solar unit temps (collector is 39degrees and the tank is at 33).

How on earth can I tell if this is working or not ?

If the combi is your sole source of hot water, then you will not get any through the taps without the boiler firing. Solar is usually allied to stored hot water, although there is a possibility that it is somehow linked in to the boiler primary circuit so that the heat is utilised. You would be best served by having an experienced person appraise the system and tell you exactly how it works. If you have a contact for the installer then that is where to go.

Unless the controls are set to limit the cylinder hot water 33 C is a very low temperature for it to reach.

In the current bright weather it should easily reach much more! Particularly if it is not being used up.

I am not sure about Worcester, but most combi boiler manufacturers do not permit the inlet water being preheated.

Tony

It's been dull all morning but is brigher now.
The solar collector is at 57 degrees C and the tank at 49 degrees C.

When I turn the tap on, it takes a minute and the boiler fires up .... it's going to be tough to find the installer of a system, maybe 8-10 years back for which I have no paperwork.

I wonder if the tank (cylinder?) is supplying the bathroom taps or shower water.

Which taps have you tested so far? Turn the boiler off while you are testing taps so you can be sure any hot water is coming from the solar supply.

Presumably you haven't got a swimming pool or underfloor heating.

I'd start by following the routes of the pipes, or getting a plumber to. Post pics and indicate which are hot.

Sooner or later you will need an experienced solar heating engineer, so you may as well start now.

Combi and Cylinder? It needs an experienced eye to instruct the OP.

Ive seen combi preheat before they work through a set of valves,one to limit temp in to the comb normally 25/30degrees and another one to direct to taps if over a preset temp normally 60 degrees settings on the controller limit the temps in the store and hysteresis between the panel and store bottom temps

Some combis take preheated water, but most don't. I'm not aware of any WB that does. Hard to imagine why anyone would install a boiler that doesn't with solar, but then it isn't at all clear what is happening with this particular system.