Heating not working as it should

[fresh9rince]

Hi, we have our heating split across 2 levels - we can control the heating for each floor.

On the Horstmann panel in the middle, there are 3 settings - heating upstairs, heating downstairs and water. I leave the heating settings on all the time, but the water is on a timer.

My understanding is that our combi-boiler provides water to the heating and water to our megaflow.

The issue we are having is that when the water setting is ON the Horstmann panel, the heating system does not work at all when turned on from the Salus thermostat.

If I turn OFF water setting on the Horstmann panel, and turn ON both the upstairs and downstairs heating from the Salus thermostats - the heating system does not work.

If I turn ON upstairs heating from the Salus thermostat, but not the downstairs thermostat - then the heating upstairs works fine and vice versa.

I don't understand why all 3 do not all work at the same time. It appears the water takes priority, and the heating only works if it is turned on individually for each floor.

We've had the system magnacleansed as we though there was a blockage. But it does not appear to have fixed the issue.

Do you any suggestions for what the problem could be?

 

[ianmcd]

First of all you do not have a Combi boiler as you stated, it could be that your system is wired PDHW (priority domestic hot water) if it is the heating wont come on until the HW cylinder is satisfied