Motor And Blower Wheel Check; Installation Data - Space-Ray LTU80-N5 Installation And Operation Instructions Manual

TO CHECK FLAME SENSOR CIRCUIT.
a. Turn off heater at thermostat.
b. Connect a meter (dc microammeter scale) in series with the ground lead as shown in the diagram. Connect
the meter as follows:
•
Disconnect the ground lead at the electronic control.
• Connect the black (negative) meter lead to the electronic control GND terminal.
• Connect the red (positive) meter lead to the free end of the ground lead.
c. Restart the system and read the meter. The flame sensor current must be steady and measure at least 1.5
microamps.
d. If the meter reads less than the minimum or if reading is unsteady:
•
Make sure burner flame is capable of providing a good rectification signal.
• Make sure fasteners securing igniter/sensor are tightened to assure correct positions. DO NOT relocate
igniter/sensor.
•
Check for excessive (over 1000ºF) temperature at ceramic insulator on flame sensor. Excessive
temperature can cause short to ground. DO NOT relocate igniter/sensor.
•
Check for cracked ceramic insulator, which can cause short to ground, and replace sensor if necessary.
• Make sure that electrical connections are clean and tight. Replace damaged wire.
e. If the meter reads below "0" on the scale, meter leads are reversed. Disconnect power and reconnect meter
leads for proper polarity.
f. Remove microammeter. Return system to normal operation.
24.5)

MOTOR AND BLOWER WHEEL CHECK

If draft inducer motor fails to run:
a. Check power supply to junction box.
b. Check for loose or broken motor lead wire.
c. Check to see that blower wheel turns freely and is not rubbing housing. Blower wheel may have worked
loose from shaft and jammed against housing.
d. Check for blower wheel damage; replace if necessary. If no damage, readjust blower wheel on shaft &
retighten set screw.
e. If all above does not correct, replace motor.
25.0)

INSTALLATION DATA

Date of
Installation:
Serial No.
Model: LTS or LTU
Form #43155010
Mar 09
# of Heaters in
System:
-51-
N = Natural Gas
L = Propane Gas