Pilot Adjustment; Primary Air Shutter Adjustment; Controls - Trane GRAA Installation, Operation And Maintenance Manual

1. Obtain the heating value of the gas from the local utility or gas dealer. This should be in units
2. Determine the gas flow rate as shown in the following example. EXAMPLE: Assume this unit
3. Before determining the gas flow rate to the unit, all other gas appliances connected to the
4. Fire unit according to instructions.
5. After approximately 15 minutes of unit operation, determine volume of gas used in five
M M e e t t h h o o d d t t o o C C h h e e c c k k M M a a n n i i f f o o l l d d P P r r e e s s s s u u r r e 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
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
5. Small variations in the manifold pressure can be made by means of the gas valve 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
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

P P r r i i m m a a r r y y L L i i m m i i t t C C o o n n t t r r o o l l : : The primary limit control is a factory installed component surface
mounted in the inlet airstream at the end of the heat exchanger. When the temperature reaches
MUA-SVX003B-EN
of Btu/ft 3 (MJ/m 3 ).
has a input rate of 250,000 Btu/hr (73.2 kW) and the heating value of the gas is 1000 Btu/ft
(37.3 MJ/m 3 ).
250,000 Btu/hr
Gas Flow Rate =
1000 Btu/ft
= 4.17 ft
same meter must be turned off.
minutes of unit operation. For the Example above the unit should use 4.17 ft
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.
of the valve.
manifold pressure from the unit rating plate.
regulator. Remove pressure regulator cap and turn regulator clockwise to increase pressure
or counter-clockwise to decrease pressure.
12.7mm) of the flame sense probe tip.
3 x 60 min/hr
3 /min
O O p p e e r r a a t t i i o o n n
3
3 /min x 5 min or
33