ECR EMI America Series Installation, Operation And Maintenance Manual page 53

Troubleshooting — CACG/CAHG Units
The indoor unit contains an electronic anti-
short-cycle timer feature (ASCT) that will
prevent the outdoor condenser from short
cycling. After the thermostat is satisfied there
will be a three (3) minute delay before the
condenser is allowed to restart.
While the remote thermostat is calling for
cooling and the ASCT delay has elapsed,
24 Vac can be measured between terminals:
• "Y" and "C" of the outdoor unit.
• "Y1" and "C" of the cassette.
• "G" and "C" of the cassette (fan signal).
Electric heat (optional)
Units with electric heat utilize a control relay
located on the circuit board in the control
box. When the remote thermostat is calling
for electric heat the relay will energize.
To check for electric heat operation, place the
remote thermostat in Heat mode with the set-
point temperature above room temperature.
1. Then place a clamp-on type ammeter on
one leg of the incoming power supply.
2. When the unit is working correctly, the
amp reading should correspond with the
values in the table below.
3. The following current values apply when
the unit is connected to a 230 Vac power
supply. These values include fan motor
current. If the supply voltage is differ-
ent, this will affect the amp draw of the
heater.
5kw = 22.7 A 3kw = 13.6 A
4. The electric heat relay can also be verified
by placing a voltmeter across the high-
voltage relay output terminal and the
incoming power L2 terminal.
5. If the unit is working correctly, the reading
should be the same as measured across the
incoming power supply.
P/N 240007756, Rev. A [051509]
CACG/CAHG & CACH/CAHH
• Installation, Operation and Maintenance Manual •
As a safety feature, an auto-reset limit switch
is located on the heater assembly.
1.
2.
3.
4.
5.
Checking fuse link
To check if the fuse link has failed requires an
Ohmmeter reading across the limit switch.
1.
2.
3.
For optional remote thermostat operation, 24
1.5kw = 6.9 A
Vac can also be measured across the Cassettes
low-voltage terminals:
•
•
53
Air Handlers
(continued)
The limit will interrupt power to the
heater if an over-temperature condition
occurs.
Each limit switch is also equipped with a
one-time fuse link.
Should electric heat temperatures rise
above the auto resetting limit switch, the
non-resetting, one-time fuse link will
open and the heater will remain off.
If this occurs the limit switch assembly
must be replaced.
Contact EMI technical service for a re-
placement.
WARNING
Electrical shock hazard
to fully disconnect all power to both the
indoor cassette and outdoor unit where
indicated in these instructions.
After disconnecting all power to the unit,
disconnect the wires from the fuse link.
Then with an ohmmeter, check the con-
tinuity across the fuse link.
If the fuse link is open, it must be re-
placed.
"G" and "C" (fan signal).
"W" and "C" (electric heat signal).
— Make sure
Made in the USA