Set Appliance State:

Mains Power Off
Gas Off
Selector Switch in Summer (I) position
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Observation:

Disconnect Ignition Electrode Lead from rear of Electrical Control Box.
Press and hold in Ignition Switch for at least 20 seconds.
Observe spark from rear of Electrical Control Box to Heating Return Valve.