281 Issue 1 - Service Manual - BX3
iv
Table of Contents
1.0 HEATER OPERATION .............................................................................. 1
1.1 Operation Overview ................................................................................... 1
1.2 Circuit Diagram ......................................................................................... 2
1.3 Wiring Colour Code ................................................................................... 3
1.4 BX315 Technical Information .................................................................... 4
1.5 BX320 Technical Information .................................................................... 5
1.6 BX326 Technical Information .................................................................... 6
1.7 Motor Wiring Diagrams .............................................................................. 7
2.0 Thermostat Installation and Wiring ............................................................ 8
3.0 COMPONENT OPERATION ................................................................... 10
3.1 BX3 Gas Ducted Unit Components ......................................................... 10
3.2 Gas Valve Operation ............................................................................... 10
3.3 Spark Igniter ............................................................................................ 11
3.4 Flame Sensor .......................................................................................... 11
3.5 Combustion Fan Operation ..................................................................... 11
3.6 Burner ..................................................................................................... 12
3.7 HCDSI24 -1 Control Board ...................................................................... 12
3.8 Pressure Switch ...................................................................................... 13
3.9 Main Fan Assembly Operation ................................................................ 13
3.10 Operation Flow Charts ........................................................................... 14
3.11 Heater “Shut down” Flow Chart ............................................................. 15
4.0 INSTALLATION & COMMISSIONING ..................................................... 16
5.0 TROUBLESHOOTING ............................................................................ 16
5.1 LED Flash Codes .................................................................................... 16
5.2 One Flash - Over Heat Condition ............................................................ 18
5.3 Two Flashes - Pressure Switch Inactive .................................................. 19
5.4 Three Flashes – Purge / Interwait ............................................................ 20
5.5 Four Flashes - Pressure Switch Lockout ................................................. 20
5.6 Five Flashes – Ignition Lockout ............................................................... 20
5.7 Six Flashes – Valve Fault Lockout ........................................................... 20
5.8 Seven Flashes – Over Temp Lockout ..................................................... 21
