Payne PG8MVA Installation Instructions Manual page 52

AIR CONDITIONING
TONS (12,000 BTU/HR)
1-1/2
2
2-1/2
3
3-1/2
4
5
6
X-INDICATES AN ALLOWABLE SELECTION.
The furnace will start up in either low- - or high- -heat. If the
furnace starts up in low- -heat, the control CPU determines the
low- -heat on- -time (from 0 to 16 minutes) which is permitted
before switching to high- -heat.
If the power is interrupted, the stored history is erased and the
control CPU will select low- -heat for up to 16 minutes and then
switch to high- -heat, as long as the thermostat continues to call for
heat. Subsequent selection is based on stored history of the
thermostat cycle times.
The wall thermostat "calls for heat", closing the R- -to- -W circuit.
The furnace control performs a self- -check, verifies the low- -heat
COOLING TONNAGE VS. AIRFLOW (CFM)
AIRFLOW 070 MODEL
(CFM)
525
700
875
1050
1225
1400
1750
2100
BASED ON 350 CFM/TON (SETUP SWITCH SW1-5 OFF, SW4-3 OFF)
SETUP SWITCH SW2 OR SW3 POSITIONS
MODEL
SIZE
070 DEF. 525 700
2
090 DEF. 525 700
2
110, 135 DEF. 700 875
2
BASED ON 400 CFM/TON (SETUP SWITCH SW1-5 ON, SW4-3 OFF)
SETUP SWITCH SW2 OR SW3 POSITIONS
MODEL
SIZE
070 DEF. 600 800
2
090 DEF. 600 800
2
DEF. 800 1000
110, 135
BASED ON 325 CFM/TON (SETUP SWITCH SW1-5 OFF, SW4-3 ON)
SETUP SWITCH SW2 OR SW3 POSITIONS
MODEL
SIZE
070 DEF. 488 651
2
090 DEF. 488 651
2
110, 135 DEF. 651 814
2
BASED ON 370 CFM/TON (SETUP SWITCH SW1-5 ON, SW4-3 ON)
SETUP SWITCH SW2 OR SW3 POSITIONS
MODEL
SIZE
070 DEF. 558 744
2
090 DEF. 558 744
2
110, 135 DEF. 744 930
2
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
Fig. 58 - - Cooling (A/C) or Continuous- -Fan (CF) Airflow Selection Chart
090 MODEL
X X
2
2
X X
X X
X X
1
X X
1
X
875 1050 1225 1225 1225
1
875 1050 1225 1400 1400
1
1050 1225 1400 1750 2100
1
1000 1200 1400 1400 1400
1
1000 1200 1400 1600 1600
1
1200 1400 1600 2000 2200
2 1
814 976 1139 1139 1139
1
814 976 1139 1302 1302
1
976 1139 1302 1627 1950
1
930 1116 1302 1302 1302
1
930 1116 1302 1488 1488
1
1116 1302 1488 1860 2200
1
and high- -heat pressure switch contacts LPS and HPS are open,
and starts the inducer motor IDM in high- -speed.
a. Inducer Prepurge Period
(1.) If the furnace control CPU selects low- -heat oper-
ation the inducer motor IDM comes up to speed,
the low- -heat pressure switch LPS closes, and the
furnace control CPU begins a 15- -second prepur-
ge period. If the low- -heat pressure switch LPS
fails to remain closed the inducer motor IDM will
remain running at high- -speed. After the low- -heat
pressure switch re- -closes the furnace control CPU
52
110 and 135
MODELS
X
X
2
X
X
X
X
1
X
A12091