Trane GXAA, Installation, Operation And Maintenance Manual

Page: 33 / 64

MUA-SVX006B-EN 33
1. Obtain the heating value of the gas from the local utility or gas dealer. This should be in units
of Btu/ft 3 (MJ/m 3 ).
2. Determine the gas flow rate as shown in the following example. EXAMPLE: Assume this unit
has a input rate of 250,000 Btu/hr (73.2 kW) and the heating value of the gas is 1000 Btu/ft 3
(37.3 MJ/m 3 ).
Gas Flow Rate =
250,000 Btu/hr
1000 Btu/ft 3 x 60 min/hr
=
4.17 ft 3 /min
3. Before determining the gas flow rate to the unit, all other gas appliances connected to the
same meter must be turned off.
4. Fire unit according to instructions.
5. After approximately 15 minutes of unit operation, determine volume of gas used in five
minutes of unit operation. For the Example above the unit should use 4.17 ft 3 /min x 5 min or
20.8 ft 3 (1.97 L/s x 5 min x 60 s/min = 591L) of gas. Minor input adjustments can be made by
removing pressure regulator cap and turning regulator clockwise to increase input or counter
clockwise to decrease input. Any appreciable adjustment in input rate should be made by
reorificing.
M Me etth ho od d tto o C Ch he ecckk M Ma an niiffo olld d P Prre essssu urre e
1. Close the manual valve of unit gas valve.
2. Install a 1⁄8 inch pipe connection in the tapped hole provided in the gas valve body near outlet
of the valve.
3. Attach manometer to 1⁄8 inch pipe connection by means of a rubber hose.
4. Fire unit according to instructions and observe the pressure and confirm it matches the unit
manifold pressure from the unit rating plate.
5. Small variations in the manifold pressure can be made by means of the gas valve pressure
regulator. Remove pressure regulator cap and turn regulator clockwise to increase pressure
or counter-clockwise to decrease pressure.
Pilot Adjustment
1. Disconnect wire from terminal marked MV at gas valve.
2. Provide call for heat.
3. Pilot adjustment is found on the gas valve. Remove pilot adjustment cap.
4. Adjust the pilot screw to provide properly sized flame.
5. A proper pilot burner flame is a soft steady flame that envelopes 3⁄8 to 1⁄2 inch (9.5 to
12.7mm) of the flame sense probe tip.
6. Replace the pilot adjustment cap.
7. Reconnect wire to terminal MV.
Primary Air Shutter Adjustment
After the unit has been in operation for at least 15 minutes, adjust the primary air flow to the
burners. Turn the friction-locked manually rotated air shutters clockwise to close, counter
clockwise to open. For correct air adjustment, close the air shutter until yellow tips in the flame
appear. Then open the air shutter to the point just beyond the position where yellow tipping
disappears.
Controls
N No otte e:: Also see the Indoor Duct Furnace Manual
O Op pe erra attiio on n