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LDAP-IOM (01-22) 207733-A
Fan
Blade
Fan
Motor
MAINTENANCE—CONTINUED
Maintenance Procedures—Continued
Maintenance of Fan Motor, Fan Blades, and Fan Guard—Continued
5 . Reassemble using replacement part(s) as needed and original parts .
6 . Ensure that fan blade is in proper position on shaft (see
) .
Figure 20. Fan Blade Positioning and Spacing
7 . Position assembly on heater and attach fan guard .
8 . Rotate fan blade to check for adequate clearance . If adjustment is required, loosen mounting screws, reposition
fan guard, and tighten screws . Repeat until assembly is positioned properly .
9 . Reconnect fan motor wires in accordance with wiring diagram .
10 . Install access panel .
11 . Restore electric power to heater and turn ON gas .
12 . Follow instructions on lighting instruction plate to light heater .
13 . Check for proper heater operation .
Combination Gas Valve Maintenance
⚠ WARNING ⚠
The combination gas valve is the prime safety shutoff. All gas supply lines must be free of dirt or
scale before connecting to the unit to ensure positive closure.
NOTE: Each heat section is equipped with a combination gas valve.
Inspect the combination gas valve, carefully remove any external dirt accumulation, and check wiring connections .
Check the valve annually to ensure that the valve is shutting off gas flow completely as follows:
1 . Turn manual shutoff valve OFF to prevent flow to gas valve .
NOTE: A manometer (fluid-filled gauge) is recommended rather than a spring-type gauge due to
the difficulty of maintaining the calibration of a spring-type gauge. Use a water column manometer
that is readable to the nearest tenth of an inch.
2 . Connect manometer to 1/8-inch output pressure tap on valve (see
) .
3 . Turn manual valve ON and heater OFF .
4 . Use finger to fully block main burner orifice for several seconds .
5 . Observe manometer with orifice blocked . If
any
pressure is indicated, gas valve is leaking .
6 . Replace leaking gas valve before heater is restored to operation .
