Gas Heat Components; Heat Exchanger; Burner Box Assembly - Lennox KGB Series Unit Information

D-GAS HEAT COMPONENTS
KGB024, 030, 036, 048, 060, 072, 074S units are avail­
able in 65,000 BTUH (19 kW) heat capacity. KG036,
048, 060, 072 074H and 090 units are available in
108,000 BTUH, (30.8 kW) heat capacity. KGA/KGB048,
060, 072 and 090 units are available in 150,000 BTUH
(44 kW) heat sizes.
Two stage heat is available in units with 108,000 and
150,000 BTUH capacities.
KGA036, 048, 060, 072 and 090 units built prior to
01/01/2014 are equipped with 105,000 BTUH heating
capacity.
Two stage heat units built prior to 01/01/2014 are
equipped with 105,000 and 150,000 BTUH capacities.
See Gas Heat Specifications on for more detail.
1-Heat Exchanger Figure 16
The KGB units use aluminized steel inshot burners with
tubular aluminized steel heat exchangers and redundant
gas valve. Burners in all units use a burner venturi to mix
gas and air for proper combustion. Combustion takes
place at each tube entrance. As hot combustion gases
are drawn upward through each tube by the combustion
air inducer, exhaust gases are drawn out the top and
fresh air/gas mixture is drawn in at the bottom. Heat is
transferred to the air stream from all surfaces of the heat
exchanger tubes. The supply air blower forces air across
the tubes to extract the heat of combustion. The shape of
the tubes ensures maximum heat exchange.
The gas valves on two stage units accomplish staging by
allowing more or less gas to the burners as called for by
heating demand.
HEAT EXCHANGER ASSEMBLY
Heat Exchanger Tubes
Combustion
Air Inducer
Burners
S10 Primary Limit
FIGURE 16
2-Burner Box Assembly (Figure 17)
The burner assembly consists of a spark electrode, flame
sensing electrode and gas valve. Ignition board A3 controls all
functions of the assembly.
Burners
All units use inshot burners. Burners are factory set and
do not require adjustment. A peep hole with cover is fur­
nished in the heating access panel for flame viewing.
Always operate the unit with the access panel in place.
Burners can be removed individually for service. Burner
maintenance and service is detailed in the SERVICE
CHECKS section of this manual.
Orifice
Each burner uses an orifice which is matched to the
burner input. The orifice is threaded into the burner
manifold. The burner is supported by the orifice and will
easily slide off for service once the mounting screws are
removed from the burners.
NOTE-Do not use thread sealing compound on the
orifices. Using thread sealing compound may plug
the orifices.
Sensor
Gas Valve
Page 46

BURNER BOX ASSEMBLY

S47 Rollout Switch
Burners
Manifold and Orifices
FIGURE 17
Gas Valve
Ignitor