A.O. Smith 28 30 50 60 service manual How to bleed air from the gas line, and measure the supply

Warning

Maintenance may only be performed by a qualified service and maintenance engineer.

Table 10.2 Displayed errors (Sheet 5 of 10)

is

Code + Description	Possible cause	Solution		Remark
F04 (lock out error)	No gas.	1.	Open the main gas valve and/or the gas valve before the gas	To repair the gas supply, contact your installer.
Three unsuccessful			control.
ignition attempts.		2.	Check supply pressure to the gas control.
		3.	If necessary, repair the gas supply.
	Air in the gas pipes.	Bleed the air out of the gas pipe.		See ’3.11 Checking the supply pressure and burner pressure’ for
				how to bleed air from the gas line, and measure the supply
				pressure and burner pressure.
	No burner pressure.	1.	Check the burner pressure at the gas control.
				To replace the necessary parts, you must contact your installer.
		2.	Check that the gas valve(s) open and shut correctly.
		3.	If necessary, replace the gas control.
	Defect in the glow	1.	Check that the glow igniter is correctly connected (JP2).	If the error persists, contact your installer.
	igniter circuit.	2.	Check the wiring of the glow igniter.	To replace the necessary parts, you must contact your installer.
		3.	Measure the resistance across the glow igniter. This must lie
			between 2 and 5 Ω.
		4.	Check that the glow igniter lights up during ignition.
		5.	If necessary, replace the glow igniter.
	Defect in the ionisation	1.	Check that the ionisation rod is correctly connected (JP2).
	circuit.	2.	Check the wiring of the ionisation rod.
		3.	Measure the ionisation current. This must be a minimum of 1.5
			∝A.
		4.	If necessary, replace the wiring.
	Supply voltage too low	Check the supply voltage to the appliance. This must be 230 VAC
		(+10% -15%).

Release R.1.3 UK 77