Air Switch Pressure Check; Ignition System Checks - Space-Ray LTU Series Installation And Operation Instructions Manual

24.3)

AIR SWITCH PRESSURE CHECK

1. Open hinged access panel.
2. Add tubing to connect the air switch with the connector tee and the existing tubing.
3. Connect plastic tubing of a digital or inclined water manometer with a 0-2" scale onto the connector tees.
4. Turn heater on and wait until blower motor is activated.
5. Observe air pressure from manometer. This should be higher than the set point indicated below for
correct operation.
Model Model
Model Model
LTS40-175, LTU80-175
LTS/U 180 - 250
All pressures are with the heater in operation for at least 15 minutes. All pressures are with the
All pressures are with the All pressures are with the
24.4)

IGNITION SYSTEM CHECKS

TO CHECK IGNITION CABLE TO CHECK IGNITION CABLE. . . .
TO CHECK TO CHECK IGNITION CABLE IGNITION CABLE
a. Make sure that the ignition cable does not touch any metal surface.
b. Make sure that connections to the stud terminal and the igniter/sensor are clean and tight.
c. Make sure that the ignition cable provides good electrical continuity.
TO CHECK IGNITION SYSTEM GROUNDING TO CHECK IGNITION SYSTEM GROUNDING. . . .
TO CHECK TO CHECK IGNITION SYSTEM GROUNDING IGNITION SYSTEM GROUNDING
(Nuisance shutdowns are often caused by a poor or erratic ground.) A common ground is required for the module,
igniter, flame sensor and main burner.
a. Check for good metal-to-metal contact between the igniter bracket and the main burner.
b. Check the ground lead from the GND (BURNER) terminal on the module to the igniter bracket. Make sure
connections are clean and tight. If the wire is damaged or deteriorated, replace it.
c. Replace igniter/sensor with factory replacement part if insulator is cracked.
TO CHECK SPARK IGNITION CIRCUIT TO CHECK SPARK IGNITION CIRCUIT. . . .
TO CHECK TO CHECK SPARK IGNITION CIRCUIT SPARK IGNITION CIRCUIT
▲WARNING: ▲WARNING: ▲WARNING: The ignition circuit generates a 20,000 Volt open circuit and electrical shock can result. ▲WARNING:
a. Check ignition cable.
b. Check external fuse located inside the draft inducer junction box.
c. Verify power (24V) at module input terminals and output terminal to gas valve.
d. Replace spark module if fuse and power are OK.
Operating Pressure Operating Pressure
Operating Pressure Operating Pressure
0.42" W.C. Hot
0.57" W.C. Hot
heater in operation for at least 15 minutes.
heater in operation for at least 15 minutes. heater in operation for at least 15 minutes.
-54-
0.37” WC
Form #43155040
May 2013