10
IMPROPER COOLING AIR FLOW -- 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--24
V on the variable speed furnace control?
8
5
5.
You have a defective thermostat, or a break in the wiring between the thermostat and the
furnace, or the Y/Y2 thermostat 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 INSTRUC-
TIONS.
INDEX
8.
Are the air conditioning airflow select switches A/C set to the proper airflow as required by
the condensing unit? Typical airflow is based on 350 CFM/TON (See Table 2.)
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.)
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 dehumidify--enabled thermostat 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--24
V on the variable speed furnace con-
trol?
18
24
18.
Do you have less than 90 vac between L1 and NEUTRAL--L2 on the variable speed fur-
nace control?
19
20
19.
Make sure the wire gage between main fuse box and furnace complies with wire size spe-
cification 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--24
V on the variable speed furnace con-
trol?
22
23
22.
Replace transformer.
7
23.
Check the thermostat wire gage between furnace and thermostat, 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