39
1.800.627.4499
Integral Indirect Gas-Fired Heat Module
OPTION
6.6 UNIT START-UP ADJUSTMENTS
6.6.1 Burner Flames
Prior to completing the start-up, check the appearance of the main burner flame. See images
below for characteristics of properly adjusted Natural Gas systems.
The burner flame should be predominantly blue in color and well defined and centered at the
tube entry. Distorted flame or yellow tipping of natural gas flame, or a long yellow flame on
propane, may be caused by lint and dirt accumulations 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 information.
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 loose dirt or
loose debris. Clean heat exchanger tubes with a stiff brush. Poor flame characteristics can also
be caused by undersized combustion air openings or flue gas recirculation into combustion air
supply. Increase air opening size or re-direct flue products to prevent recirculation.
Reduced air delivery can also be the result of fan blade slippage, dirt accumulation on the fan
blade or low voltage to draft inducer motor. Inspect draft fan assembly and be sure the fan
blade is secure to motor shaft. Check the line voltage to the module.
The high-fire settings on the gas valve(s) have been factory-set using the maximum manifold
gas pressure as shown on the data label.
IMPORTANT
FIGURE 6.6.0 BURNER FLAME AT 1.2 INWC [298 PA]
MANIFOLD PRESSURE (DRAFT INDUCER AT HIGH SPEED)
FIGURE 6.6.1 BURNER FLAME AT HIGH FIRE 3.5 INWC [871 PA]
MANIFOLD PRESSURE (DRAFT INDUCER AT HIGH SPEED)
OPERATION
