Operation; General Information - Trane GRAA Installation, Operation And Maintenance Manual

Operation

General Information

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Figure 14. Burner Components — Intermittent Pilot Ignition (Natural or Power Vented Duct
BURNER DRAWER COMMON PARTS:
1.
2.
3.
4.
5.
6.
7.
5
CONTROLS:
8A. MAIN GAS VALVE (HONEYWELL)
8B. MAIN GAS VALVE (WHITE RODGERS)
9.
10.
26
All units are equipped with intermittent pilot ignition systems. This system is 100% pilot
burner shut off. See for burner/gas controls. The pilot is lit and extinguished during every
cycle of operation. There is no burning standing pilot.
On natural gas units, the ignitor will spark and pilot gas will continue to flow until the pilot
flame is proven.
LP (propane) gas units are equipped with 100% lockout. The lockout function shuts off the
main and pilot gas valves if the pilot gas fails to ignite within 30 seconds. In order to initiate a
re-ignition trial, the power supply must be interrupted for a minimum of 5 minutes to allow
dispersion of unburned gas.
N N o o t t e e : : Check gas supply pressure (see Table 4 below). Gas valves are suitable to a maximum
pressure of 0.5 psi (14 inches water column). If the main gas supply pressure for
natural gas is greater than 14 inches WC (3.5 kPa), a step-down pressure regulator
must be installed ahead of the gas valve. For LP (propane) gas, the gas pressure
supplied should not exceed 14 inches WC (3.5 kPa).
The controls are located inside the compartment on the access side of the unit. The input for
single-stage firing is based on full fire. On two-stage fire, the unit will fire 50% of full fire on
the first stage and full fire on the second stage. When electronic modulating is used, the unit
will first fire at 100% of full fire and modulate down to 40% of full fire.
MAIN BURNERS
BURNER MANIFOLD
AIR SHUTTERS
BURNER SPRINGS
MAIN BURNER ORIFICE
TRANSFORMER
PILOT TUBING
1
3
4
HONEYWELL IGNITOR
PILOT BURNER
8A
Furnaces)
6
8B
10
C
7
9
1
2
3
4
5
6
7
8
9
MUA-SVX004B-EN