Manitowoc Ice QF2300, QF0800, QC0700 Electrical System, Section, 6-58, Diagnosing Start Components

Electrical System Section 6

Diagnosing Start Components

If the compressor attempts to start, or hums and trips the overload protector, check the start components before replacing the compressor.

CAPACITOR

•Visual evidence of capacitor failure can include a bulged terminal end or a ruptured membrane. Do not assume a capacitor is good if no visual evidence is present.

•A good test is to install a known good substitute capacitor.

•Use a capacitor tester when checking a suspect capacitor. Clip the bleed resistor off the capacitor terminals before testing.

RELAY

The relay has a set of contacts that connect and disconnect the start capacitor from the compressor start winding. The contacts on the relay are normally closed (start capacitor in series with the start winding). The relay senses the voltage generated by the start winding and opens the contacts as the compressor motor starts. The contacts remain open until the compressor is de- energized.

!Warning

Disconnect electrical power to the condensing unit before proceeding.

Relay Operation Check

1.Disconnect wires from relay terminals.

2.Verify the contacts are closed by checking for continuity between terminals:

		RFC2085/
QF400	QC700/QF800	RFC2385
		(QF2200/QF2300)
10 & 11	1 & 2	1 & 2

No continuity indicates open contacts. Replace the relay.

3.Check the relay coil. Measure the resistance between terminals:

		RFC2085/
QF400	QC700/QF800	RFC2385
		(QF2200/QF2300)
10 & 11	1 & 2	1 & 2

No resistance indicates an open coil. Replace the relay.

4.Replace control box cover and restore electrical power to the ice machine.

!Warning

Replace control box cover before proceeding.

5.Move toggle switch to the ICE position.

6.The compressor start winding should energize for less than 1 second. Continued high amperage draw could indicate:

•Low incoming power supply (Check voltage at compressor start-up when load is greatest)

•Defective relay

•Defective capacitor

•Defective compressor

•Verify voltage and replace all start components.

7.If all of the previous tests are satisfactory and the compressor will not operate or continue to operate, replace the compressor.

6-58 Revised 8/2003 Part No. 80-1214-3