Miller Electric 251 NT Low weld output Check control settings, See engine manual, Necessary parts

Trouble	Remedy
Low weld output.	Check control settings.
	Place Remote Amperage/Voltage switch in Panel position, or move switch to Remote 14 position and
	connect remote amperage/voltage control to Remote 14 receptacle RC1.
	Check and clean air cleaner as necessary (see Section 7-3).
	Check and adjust engine speed (see Section 7-6).
	Have Factory Authorized Service Agent check brushes, slip rings, and field current control board PC2.
	See engine manual.
High weld output.	Check control settings.
	Check and adjust engine speed (see Section 7-6).
	Check for obstructed movement of solenoid linkage (see Section 7-6).
	Have Factory Authorized Service Agent check field current control board PC2.
Weld output cannot be adjusted.	Check position of Remote Amperage/Voltage switch (see Section 5-1).
	Have Factory Authorized Service Agent check field current control board PC2.
Erratic weld output.	Check control settings.
	Clean and tighten connections both inside and outside unit.
	Check and secure lead connections to A/V control.
	Be sure connection to work piece is clean and tight.
	Remove excessive coils from weld cables.
	Use dry, properly stored electrodes.
	Check and adjust engine speed (see Section 7-6).
	Have Factory Authorized Service Agent check brushes, slip rings, and field current control board PC2.
Remote contactor control does not	Place Output (Contactor) switch in Remote 14 position (see Section 5-1).
activate contactor.
	Check and tighten connections to Remote 14 receptacle RC1 (see Section 4-8).
No power output at Remote 14	Reset circuit breaker CB1 and/or CB2 (see Section 7-7).
receptacle RC1.
Lack of high frequency; difficulty in	Use proper size tungsten for welding amperage.
establishing Gas Tungsten Arc Weld-
ing arc.
	Reduce leakage of high frequency from torch or work cable (check grounding, remove excessive
	coils from weld cables, use shorter weld cables, etc.).
	Check cables and torch for cracked or deteriorated insulation or bad connections. Repair or replace
	necessary parts.
Wandering arc – poor control of arc	Reduce gas flow rate.
direction.
	Select proper size tungsten. Properly prepare tungsten.
Tungsten electrode oxidizing and not	Shield weld zone from drafts.
remaining bright after conclusion of
weld.
	Increase postflow time.
	Check and tighten all gas fittings.
	Properly prepare tungsten.

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