Help! Boiler High Flow Temp Lockout.

[kashmachine]

I've been having issues with my Evohome setup ever since it was installed. The heating is in an S Plan config. The original design is an Ideal Logic Heat only 30Kw Boiler, external pump (no pump over rum facility on boiler), Spring Loaded Automatic Bypass, stored hot water valve and 2 motorised hearing valves.

With the installer of Evohome, the stored HW valve has Converted with the Evohome Hot Water kit and the motorised valves have been electrically disconnected and manually opened. The system is convention TPI, (Non- Opentherm).

All radiators in the property (21 in total / split into 12 zones) have HR92's.

The problem I'm facing is that post demand, the boiler flow temp increases rapidly above 95C, causing a lockout 'L1' fault on the boiler. I believe this is due to the lack of an pump over run facility on the boiler and the heat having nowhere to go. I have tried to open some rad valves, however as the pump is directed operated by the boiler, when the boiler demand is complete the pump switches off.

Any ideas on what might fix this? I have attached a picture of the SL1/SL2 Connections in the boiler, can someone confirm if they are correct?

Thanks in advance.