IMPROPER COOLING AIRFLOW — Generally, this indicates the Y/Y2 thermostat lead is not properly
connected.
STEP ACTION YES NO GO TO
1
Remove blower access panel and depress door switch. Use
a piece of tape to hold switch closed.
2
2
Set thermostat to call for cooling. If thermostat does not
have G connection jumper across thermostat terminals R
and G.
3
3
Make sure thermostat fan control is in the AUTO position if
equipped.
4
4
Do you have 24-vac across Y/Y2 and C
OM-24V on the vari-
able speed furnace control?
85
5
You have a defective thermostat, or a break in the wiring
between the thermostat and the furnace, or the Y/Y2 ther-
mostat terminal is not wired to the thermostat.
6
6 Fix the problem 7
7
Go to page number indicated in Index for CLEANUP AND
START-UP INSTRUCTIONS.
INDEX
8
Are the air conditioning airflow select switches A/C set to
the proper airflow as required by the condensing unit? Typi-
cal airflow is based on 350 CFM/TON (See Table 2 and
2a.)
10 9
9
Set the air conditioning airflow select switches A/C to the
proper airflow as required by the condensing unit. (See
Table 2 and 2a.)
7
10 Disconnect the G thermostat lead or jumper if used. 11
11
Does the blower motor turn off in 5 seconds when the G
thermostat lead is disconnected?
Note: When using a Thermidistat the blower may change
airflow when the G thermostat lead is disconnected and a
call to dehumidify is active.
12 13
12 Replace the variable speed furnace control. 7
13
Reconnect the G thermostat lead or jumper and observe
operation of furnace in cooling mode for 10 minutes.
14
14 Does the furnace operate properly in cooling mode? 15 16
15
- Check outdoor unit for correct suction pressure and verify
charge.
- Check filter(s) and ductwork for restrictions.
- Check furnace coil.
INDEX
16
Does the AMBER LED abruptly shut off as the blower
comes up to speed?
17 24
17
Do you have less than 17 vac between R and C
OM-24V on
the variable speed furnace control?
18 24
18
Do you have less than 90 vac between L1 and
NEUTRAL-L2 on the variable speed furnace control?
19 20
19
Make sure the wire gage between main fuse box and fur-
nace complies with wire size specification in Installation,
Start-Up, and Operating Instructions.
6
20 Disconnect the R thermostat lead. 21
21
Do you have less than 17 vac between R and C
OM-24V on
the variable speed furnace control?
22 23
22 Replace the transformer 7
23
Check the thermostat wire gage between furnace and ther-
mostat, and furnace and outdoor unit. It is recommended
that AWG No. 18 color-coded copper thermostat wire be
used for lengths up to 100 ft. For wire lengths over 100 ft,
use AWG No. 16 wire.
6
24 Is Status Code 41 flashing? 25 26
25
Go to the page number indicated in the Index for Status
Code 41.
INDEX
26
- Check outdoor unit for correct suction pressure and verify
charge.
- Check furnace coil.
7
12
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