Haier AC-8888-107 Service Manual page 37

electrical characteristics.
CONDENSER FAN BLADE LOCATION
Dimension "A" will be from 2" to 4" depending on the unit model number. Be sure to check this dimension
BEFORE removing the fan blade.
Note: When parts combination results in motor /blade interference ,the fan blade should be located to provide 1/8"
motor /blade clearance.
RELAYS
ELECTRICAL OPERATION
Relay coils are wires would around an steel core. When energized a coil becomes a magnet opening or closing
contactors, that makes or breaks electrical circuits. Electrical continuity indicates a good coil. Relay coils use
specific voltage. Using the wrong voltage either destroy the relay or it just doesn't operate .Avoid this by using
the proper replacement part for a failed component.
Relay contacts are switched and can become pitted or corroded, creating resistance .Corrosion can generate
enough heat to weld the contacts together. Physical examination of the contacts shows this problem. With sealed
relays ,use an ohmmeter to show open or closed contacts.
ELECTRICAL CHECKS
1. BE SURE ALL THE ELECTRICAL POWER IS OFF TO THE COMPONENT BEING CHECKED.
2. Remove at least one wire from the component being checked.
3. Measure the resistance of the holding coil with an ohmmeter
A. A special resistance indicates a good holding coil.
B. Infinite (∞) resistance indicates a relay with an open holding coil. REPLACE this relay with an identical
part.
4. Measure the resistance across the normally closed (NC) relay contacts.
A. The resistance should be zero (0) ohms.
B. If the resistance is more than 0.2 ohms the contacts are pitted .REPLACE this relay with an identical
part.
5. Measure the resistance across the normally open (NO) relay contacts.
A. The resistance should be Infinite (∞)
B. If the resistance isn't Infinite (∞),.REPLACE this relay with an identical part.
MECHANICAL CHECKS
In relays ,mechanical faults are few. with the exception of physical damage .
AIR FLOW
Indoor coil air flow in any air conditioning system is critical. Too much air and the customer suffers lack of the
dehumidification in cooling. Too little air in cooling and coil may freeze.
Check air flow is the most important checks. Instructions can measure pressure drop across the coil .If pressure
36
Commercial Air Conditioner
Fig 10-4
Fig.10-5
Model: heat pump, 10SEER UNITS