11
Table 2 – Cooling Tonnage vs. Airflow (CFM)
AIR CONDITIONING TONS
(12,000 BTU/HR)
AIRFLOW (CFM)
040, 060, &
3T---080 MODEL
5T---080 & 100
MODEL
120 MODEL
1 --- 1 / 2 525 X
2 700 X X X
2 --- 1 / 2 875 X X X
3 1050 X X X
3 --- 1 / 2 1225 X X X
4 1400 X X
5 1750 X X
6 2100 X
525
2 
700
2 
700 
875  1050 
875 
700  875
2 
1050 
1050
1 
1225 
1225 
1225 
1400 
1400 
1225 
1750
1 
1750
1 
1225 
1750 
2100 
DEF. 
DEF. 
DEF. 
040, 060, 3T-080 
5T-080, 100 
120 
BASED ON 350 CFM/TON (SETUP SWITCH SW1-5 OFF) 
SETUP SWITCH SW2/SW3 POSITIONS  
MODEL 
SIZE 
 
600
2 
800
2 
800 
1000  1200 
1000 
800  1000
2 
1200 
1200
1 
1400 
1400 
1400 
1600 
1600 
1400 
2000
1 
2000
1 
1400 
2000 
2100 
DEF. 
DEF. 
DEF. 
040, 060, 3T-080 
5T-080, 100 
120 
BASED ON 400 CFM/TON (SETUP SWITCH SW1-5 ON) 
1. DEFAULT A/C AIRFLOW WHEN A/C SWITCHES ARE IN OFF POSITION 
2. DEFAULT CONT. FAN AIRFLOW WHEN CF SWITCHES ARE IN OFF POSITION 
3. SWITCH POSITIONS ARE ALSO SHOWN ON FURNACE WIRING DIAGRAM
 
SETUP SWITCH SW2/SW3 POSITIONS
 
 
MODEL 
SIZE 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
A10472
Air Conditioning or Continuous Fan Airflow Selection Chart
HIGH HEAT TEMPERATURE RISE TOO LOW -- Generally, this indicates the HI solenoid
in gas valve GV has failed or the furnace is extremely underfired.
STEP ACTION YES NO GO TO
1. Remove the blower access panel. Disconnect the R thermostat lead from the furnace con-
trol board. If setup switch SW1--2 is ON then set it to OFF.
2
2. Depress the door switch. Use piece of tape to hold it closed. 3
3. Jumper R and W/W1 thermostat terminals. 4
4. When the furnace is running in low heat, clock the low heat gas rate. You have 16 minutes
on this first call for heat before unit switches to high heat. On propane installations check
the manifold pressure.
5
5. When the furnace is running in high heat, clock the high heat gas rate. On propane installa-
tions check the manifold pressure.
6
6. Is the high heat rate approximately the same as the low heat rate? 7 11
7. Do you have 24 vac across gas valve terminals HI and COM--24V on 2--stage gas valve dur-
ing high heat?
10 8
8. You have an open wire or bad terminal on the BROWN wire from the high heat pressure
switch HPS to the gas valve GV. Repair it or replace the harness.
9
9. Go to the page number indicated in Index for the CLEANUP AND STARTUP INSTRUC-
TIONS.
INDEX
10. Replace the gas valve. 9
11. Is the high heat rate within 2% of that specified on the rating plate? 13 12