Carrier 52C manual Disconnect ALL Power to Unit, Acceptable Heater Resistance Values

■TOOLS NEEDED — The following list includes rec- ommended tools and devices for working on the heater section of 52C,P units.

Phillips Head Screw Driver

Needle Nose Pliers

Volt-ohmmeter

Nut Driver 5/16-in.

Perform the following steps to remove the Heater

Assembly.

1.DISCONNECT ALL POWER TO UNIT.

2.Remove heater by following instructions in ACCESSING UNIT COMPONENTS section.

After the heater is removed, examine the heater as follows to determine if it is operational:

Perform a visual inspection. The heater coil should be free of breaks. If there are any breaks in the coil, replacement of the heater assembly is necessary. See Figure 35.

FIGURE 35 — HEATER COIL (Removed)

Coil resistance must also be checked to verify the heater is operating correctly. The resistance of the heater coils must meet approximate levels for the heater to perform at its optimum efficiency. See Figure 36 for approximate resistance for heaters at 75 F. Before checking the heater coil resistance, be sure all power to unit is off.

To check resistance, set the volt-ohmmeter selector switch to the lowest ohms value. Next connect the volt- ohmmeter leads to each side of the heater coil at the studs that hold the limit switches in place. Incorrect readings can be obtained if the wires are not removed from the limit switches on the heater assembly. If the resistive reading is infinite or zero, the heater is failed and replacement is necessary. Reinstall the heater assembly.

HEATER SIZE	WATTS	VOLTS	ACCEPTABLE RESISTANCE
			(Ohms)
2.3 kW	2300	230	20-23
	2300	265	28-31
3.4 kW	3400	230	13-16
	3400	265	19-21
5.0 kW	5000	230	9-11
	5000	265	13-15

FIGURE 36 — ACCEPTABLE HEATER

RESISTANCE VALUES

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