Modine Manufacturing BAE - Manual (Page 22)

Combustion Problem Symptoms and Diagnosis
To realize full gas heating value requires periodic inspections with
proper combustion control corrections as outlined and illustrated
here.
1. Lifting Flames
Lifting flames rise unevenly above the burner port and may
occur on few or all the ports. Sometimes the flames drop and
lift intermittently. Lifting can be eliminated by reducing primary
air. If flame cannot be adjusted properly, check input rate to
heater and manifold gas pressure; reduce if necessary. Check
the orifice size with those listed in Table 5 to be sure the unit
is not operating over rated input.
22
SERVICE INSTRUCTIONS – GENERAL
Troubleshooting Guide
Figure 14
Manifold Adjustment, Natural Gas Figure 15
Air Shutter Adjustment, Propane Gas
Figure 18
Lifting Flame Condition
ONLY PEOPLE TRAINED AND FAMILIAR WITH THE
OPERATION OF UNIT HEATERS AND THEIR CONTROLS
SHOULD SERVICE THIS UNIT.
General Maintenance
1. Service air moving components annually.
a. On propeller units this includes checking motor for
lubrication if motor is not the permanently lubricated
type and check fan for fit on motor shaft and for
damage to blades.
b. On blower units this should include:
(1) Checking motor and blower bearings for lubrication.
(2) Checking belt and sheaves for proper alignment
and adjustment.
(3) Checking cleanliness of blower wheel and filters.
2. Keep unit free from dust, dirt, grease, and foreign matter,
paying particular attention to:
a. Combustion air inlets.
b. Burner ports, pilot burner, and main burner orifices
(avoid use of hard, sharp instruments capable of
damaging surfaces, for cleaning these ports.) If air
pressure is abailable, use air hose to blow dirt and other
foreign matter from within the burner. Also main burner
orifices should be checked for blockage due to spider
webs, etc.
c. Primary air shutters (when used).
d. Clean heat exchanger tubes from bottom with stiff brush
after removing burner (Do not use wire brush).
e. Bottom pan.
f. Fan blade.
3. Check wiring for possible loose connections.
4. Controls – See control instruction sheets furnished
separately with the unit heater.
To Remove Main Burner
1. Turn off all electricity and gas to unit.
2. Lower bottom pan to expose burner and manifold. See
Figure 1A, Page 2.
3. Disconnect pilot tubing and thermocouple lead (or ignition
cable) at the combination gas control (and ignition control.)
4. Remove the two burner retaining pins holding the burner in
place. The burner can then be easily lowered from the unit.
In replacing the burner, be certain that the slots at the front
of the burner are located properly on their shoulder rivets
and that the burner retaining pins are put back into their
proper locations.
MANIFOLD MANIFOLD
MIXER
TUBES
MIXER
TUBES BURNER
RETAINING PIN
MAIN
BURNER
ORIFICES
MAIN
BURNER
ORIFICES
AIR
SHUTTER
MANIFOLD MOUNTING
SCREW AND PIN
Heater Parts from ACF Greenhouses