Trane OA1D OA2D OA3D (Indirect Gas-Fired/Electric Heat) Manuale Di Manutenzione

38

 OAU-SVX01E-EN

Control can be brought out of lockout by cycling call 
for heat at the Main Unit Display.

Prior to completing the start-up, check the appearance 
of the main burner flame. Refer to 

flame characteristics of properly adjusted natural gas 
systems.

The burner flame should be predominately blue in 
color and well defined and centered at the tube 
entry as shown in 

 above. Distorted flame 

or yellow tipping of natural gas flame, or a long 
yellow flame on propane, may be caused by lint and 
dirt accumulation inside burner or at burner ports, 
at air inlet between burner and manifold pipe, or 
debris in the main burner orifice. Soft brush or 
vacuum clean affected areas.

Poorly defined, substantially yellow flames, or 
flames that appear lazy, indicate poor air supply to 
burners or excessive burner input. Verify gas 
supply type and manifold pressure with rating 
plate.

Poor air supply can be caused by obstructions or 
blockage in heat exchanger tubes or vent discharge 
pipe. Inspect and clean as necessary to eliminate 
blockage. Vacuum any dirt or loose debris. Clean 
heat exchanger tubes with stiff brush. Poor flame 
characteristics can also be caused by flue gas 
recirculation into combustion air supply. If 
surrounding buildings or prevailing winds cause 
recirculation, a flue extension may be required to 
prevent recirculation. Contact manufacturer prior 
to making any flue adjustments.

Reduced air delivery can also be the result of 
inducer fan blade slippage, dirt accumulation in the 
fan blade or low voltage to draft inducer motor. 
Inspect draft fan assembly and be sure fan blade is 
secure to motor shaft. Check line voltage to heater.

Flame current is the current which passes through the 
flame from the sensor to ground. A flame signal of 0.5 
to 1.0 microamp (

μA) is marginal. For dependable 

operation, a flame signal of greater than 1.0 

μA is 

required. To measure flame current, connect a meter 
capable of reading micro-amp current so the flame 
signal will be read thru the meter’s COM and 

μA 

connections. The meter should read greater than 
1.0 

μA.

Burner flame at start-up: 1.2 in. wc manifold pressure 
draft inducer—high speed

Burner flame at high fire: 3.5 in. wc manifold pressure 
draft inducer—high speed