Misbehaving Systemate 2000

Mike
Any ideas where we go next

Systemate 2000 heating coming on without being called for, we have drained system and replaced both check valves, I think the heating pump was changed just before we got involved. When heating is off or thermostat is down there is no power to pump and not spinning

Every time we visit we pick up some more info, the faults all started after one rad was not heating up, previous engineer shut down all other rads to force through, after this the whole system either stopped heating or only comes on at certain times

The system does have microbore to the rads, water was dirty so powerflushed to clean, this now gets the radiators very hot even when switched off, at the same time the hot water store is not reaching temperature even though the output from boiler is near 80 degrees.

the client has also mentioned that they think the two towel rails are connected to hot water although I cant see any connections to the store for this. How is this normally achieved? do they connect direct to boiler flow pipe? How will this affect the circulation of heating system?

Obviously the primary is being sucked around the heating circuit, any idea how this is happening, as mentioned above both check valves have been changed.

The closest radiator to the store is in hall where room stat is located, should this be left full open, what affect will this have? the bypass on the store is set to 3 Bar.

Any ideas where what checks we should do next as we seem to be going around in circles with this one.

Auto bypass valve?
Page 14 of the manual ref towel rails
Cut the lock shields down on the towel rails.
When heating is running and it should not be, check if a supply at the heating pump?
When you power flushed the system did you do the System mate too?
Checked the ACB for fault codes?
Is the ACB giving a normal display?
Has any others moved the jumpers on the ACB?
Mike
MGC/H2O
Norwich
Norfolk