Manitowoc EC18, Technician'S Handbook

Page: 46 / 184

34 Part Number 80-1479-3 10/10
Compressor Drawing High Amps
The continuous amperage draw on start-up should not
be near the maximum fuse size indicated on the serial
tag.
The wiring must be correctly sized to minimize voltage
drop at compressor start-up. The voltage when the
compressor is trying to start must be within (6% of the
nameplate voltage).
Compressor Drawing Locked Rotor
The three likely causes of this are:

Low voltage supply (check voltage while
compressor is trying to start)

Defective starting component

Mechanically seized compressor
To determine which you have:

Install high and low side gauges.

Try to start the compressor.

Watch the pressures closely.
If the pressures do not move, the compressor is
seized. Replace the compressor.
If the pressures move, the compressor is turning
slowly and is not seized. Check the capacitors and
relay.