Trane GRAA, Installation, Operation And Maintenance Manual

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MUA-SVX004B-EN 39
Maintenance
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IIm mp po orrtta an ntt:: Gas tightness of the safety shut-off valves must be checked on at least an annual
basis.
• To check gas tightness of the safety shut-off valves, turn off the manual valve upstream of the
appliance combination control. Remove the 1/8 inch pipe plug on the inlet side of the
combination control and connect a manometer to that tapping. Turn the manual valve on to
apply pressure to the combination control. Note the pressure reading on the manometer,
then turn the valve off. A loss of pressure indicates a leak. If a leak is detected, use a soap
solution to check all threaded connections. If no leak is found, combination control is faulty
and must be replaced before putting appliance back in service.
• Rooftop duct furnaces have been developed for outdoor installation. Should maintenance be
required, perform the following inspection and service routine: Inspect area near the unit to
be sure that there is no combustible material located within minimum clearance
requirements (refer to
Figure 1, p. 9 , Figure 2, p. 10 , and Figure 6, p. 16 . Service panels
provide easy access to the burner controls. To remove the service door, refer to “Access
Panel Removal” section (In the General Safety Information chapter).
• The pilot burner can be serviced by removing the pilot plate from the main burner assembly.
To remove the main burner drawer assembly for servicing the burners, proceed as follows:
1. Shut off the main gas valve and electrical power to the gas duct furnace.
2. To slide out the burner drawer, the following two procedures (a or b) may be chosen
depending on the complexity of the unit's controls:
a. Disconnect the pilot burner gas tube. Break the union between the automatic gas valve
and the burner manifold. Also break the union on the discharge air end of the furnace
(inside the unit). Loosen the union located directly outside of the furnace's bottom panel
(refer to
Figure 12, p. 22 in the Gas Connections chapter). Swing down this end of the
piping to clear the bottom of the burner drawer. The control and piping assembly may be
tied out of the way of the pull-out drawer.
b. Disconnect all wiring to the unit's controls. Break the union located in the discharge end of
the furnace; loosen the external union, and swing piping clear of the bottom of the drawer
(same procedure as ‘a’).
3. Remove the locking screws holding the burner drawer in position.
4. Slide the drawer out of the furnace.
5. Burners can be removed from the drawer by raising the front of the burner and pushing it
against the hold-in spring until the front of the burner comes out of the slot.
6. To clean or replace the main burners, slide out the pullout drawer, and compress the spring
by moving the burner toward the manifold. Slide the opposite end of the burner downward