LAir Pressure Switch Check
Remove BROWN and
WHITE terminals from air pressure switch
With no demand, is a
at exposed APS
terminals?
Air pressure switch
faulty
YES
Reconnect the
WHITE & BROWN
wire and remove the GREEN wire. Initiate
ademand. Does the fan run?
YES
With fan running
disconnect BROWN wire. (DO NOT touch chassis with it). Is a short circuit observed across exposed APS
terminals?
NO | Is there mains 230V | NO |
| at fan connector X4 | PCB faulty |
|
| |
| pins 1 and 3? |
|
| YES |
|
| Fan or fan cable |
|
| faulty |
|
NO | Air pressure switch |
|
| faulty |
|
YES
APS OK
Gas Valve Check
Is gas pressure present | NO | Ensure gas supply |
at input to gas valve? |
| |
|
| |
YES |
|
|
Is live output present at | NO | Faulty board |
X5 pins 1 & 2 relative to |
| Replace |
neutral at pin 3? |
| |
|
|
YES
Is gas pressure present NO at input to burner?
YES
Gas valve OK
Faulty gas valve
Replace
32
