Cooling Or Continuous Airflow; Check Safety Controls - Carrier 58CU0A Series Installation, Start-Up, Operating And Service And Maintenance Instructions

Model Size
3T-040
4T-060
5T-080
5T-100
Model Size
3T-040
4T-060
5T-080
5T-100
Model Size
3T-040
4T-060
5T-080
5T-100
Model Size
3T-040
4T-060
5T-080
5T-100
(1.) Default A/C airflow when A/C switches are in OFF position
(2.) Default continuous fan airflow when CF switches are in OFF position
(3.) Switch positions are also shown on furnace wiring diagram

Check Safety Controls

1. Check Main Limit Switch(es)
This control shuts off combustion control system and en-
ergizes air- -circulating blower motor, if furnace overheats.
By using this method to check limit control, it can be es-
tablished that limit is functioning properly and will operate
if there is a restricted duct system or motor failure. If limit
control does not function during this test, cause must be
determined and corrected.
a. Run furnace for at least 5 minutes.
b. Gradually block off return air with a piece of cardboard
or sheet metal until the limit trips.
c. Unblock return air to permit normal circulation.
d. Burners will re- -light when furnace cools down.
2. Check draft safeguard switch.
The purpose of this control is to cause the safe shutdown
of the furnace during certain blocked vent conditions.
a. Verify vent pipe is cool to the touch.
BASED ON 350 CFM/TON (SETUP SWITCH SW1---5 OFF, SW4---3 OFF)
DEF 525
DEF 525
DEF 700
DEF 700
BASED ON 400 CFM/TON (SETUP SWITCH SW1---5 ON, SW4---3 OFF)
DEF 600
DEF 600
DEF 800
DEF 800
BASED ON 325 CFM/TON (SETUP SWITCH SW1---5 OFF, SW4---3 ON)
DEF 488
DEF 488
DEF 650
DEF 650
BASED ON 370 CFM/TON (SETUP SWITCH SW1---5 ON, SW4---3 ON)
DEF 558
DEF 558
DEF 744
DEF 744
Fig. 42 - - Cooling (A/C) or Continuous Fan Airflow Selection Chart
SETUP SWITCH SW2 OR SW3 POSITIONS
700 875
2
700 875
2
875 1050
2
875 1050
2
SETUP SWITCH SW2 OR SW3 POSITIONS
800 1000
2
800 1000
2
1000 1200
2
1000 1200
2
SETUP SWITCH SW2 OR SW3 POSITIONS
650 813
2
650 813
2
813 975
2
813 975
2
SETUP SWITCH SW2 OR SW3 POSITIONS
744 930
2
744 930
2
930 1116
2
930 1116
2
b. Disconnect power to furnace and remove vent connec-
tor from furnace vent elbow.
c. Restore power to furnace and set room thermostat
above room temperature.
d. After normal start- -up, allow furnace to operate for 2
minutes, then block vent elbow in furnace 80 percent
of vent area with a piece of flat sheet metal.
e. Furnace should cycle off within 2 minutes. If gas does
not shut off within 2 minutes, determine reason draft
safeguard switch did not function properly and correct
condition.
f. Remove blockage from furnace vent elbow.
g. Switch will auto- -reset when it cools.
h. Re- -install vent connector.
32
1050 1225 1400
1
1050 1225 1400
1225 1400 1750
1225 1400 1750
1200 1400 1400
1
1200 1400 1600
1400 1600 2000
1400 1600 2000
975 1138 1300
1
975 1138 1300
1138 1300 1625
1138 1300 1625
1116 1302 1400
1
1116 1302 1488
1302 1488 1860
1302 1488 1860
1400
1400
1
2100
1
2100
1
1400
1600
1
2200
1
2200
1
1300
1300
1
1950
1
1950
1
1400
1488
1
2200
1
2200
1