John Wilson, Ravenheat's technical service and training manager, talks about how to identify potential issues with fans on older, atmospheric boilers. This includes swollen bearings and the potential causes of flame failures.
Great videos I have csi 85 with a fault on central heating only , the hot water is fine when initiated. but when heating is called on it just keeps firing up cutting off ?? Any ideas
I fail to see how a stiff bearing has ANY relationship to the resistance of the motor "coil winding" ? Surely - coil resistance is purely a function of the coil itself - ie - the number of turns of copper wire in the coil ( assuming it is copper) - ie length of winding for a given wire cross sectional area - under normal / correct circumstances ( ignoring temperature) Possible coil failure modes would be : shorted turns in the coil winding ( due to aging / breakdown of the enamel insulation of the copper winding wire / mechanical damage) which would "partially lower" the resistance - and cause "excessive coil current" when alternating current is applied during operation - due to the induced current effect into those shorted turns - and cause subsequent overheating of the coil and almost certainly cause eventual total breakdown of the whole winding ( ie "terminal failure" ) Quite difficult perhaps to spot this by just measuring resistance on its own - as shorted turns across say an adjacent layer of coil winding as might happen -would only produce a small reduction in resistance . Measuring INDUCTANCE of the coil however would show up due to the induced current effect in the shorted turns . So - moral is : measure resistance AND inductance !! Or - high resistance due to breaks in the winding ( most likely measure as very high resistance or open circuit) or poor / damaged coil terminations. in either case - the motor is unlikely to run at all in this case ( unlike the shorted turns scenario above) Either way - totally independent of the mechanical constraints of the motor shaft ease of rotation ?
