Primary Heat Exchanger Fixings Kit GB24 SIIGB24 SII ErPGB30 SIIGB30 SII ErPGB24 SII Combustion CircuitGB30 SII Combustion CircuitGB24 SII Combustion CircuitGB30 SII Combustion Circuit Description Primary Heat Exchanger Fixings KitCompatibility GB24 SIIGB24 SII ErPGB30 SIIGB30 SII ErPDiagrams GB24 SII Combustion CircuitGB30 SII Combustion CircuitGB24 SII Combustion CircuitGB30 SII Combustion Circuit