3
MAIN
BURNER
ADJUSTMENTS
Satisfactory oven performance and burner life are dependent on correct burner adjustment. Before
shipment, burners have been adjusted for proper operation with the type specified on the rating plate
located inside the control compartment above the light switch. If further adjustment is necessary proceed
as follows:
Adjust primary air shutter at the front of the burner compartment to obtain a stable and quiet
flame.
If too much primary air is present, flames will lift from the burner parts. A reduction in
primary air will correct this condition.
Too little primary air will cause yellow tipping or an entire yellow flame to appear. This
condition indicates incomplete combustion and may cause carbon sooting to appear on metal
parts near the flame.
When a flame raises off the burner it is important to determine if it is a “lifting flame” or a
“floating flame”:
o
“Lifting flames” rise from the ports to burn some distance above the ports. In some
cases these flames will drop back to the port and lift again intermittently. They are
caused by too much primary air. Decreasing the shutter opening will stop lifting
flames.
o
“Floating flames” are long and lazy in appearance, poorly defined, quiet flames
which roll around the combustion chamber sometimes completely off the ports.
Floating flames result from too little secondary air. Lack of secondary air is caused
by incorrect venting, clogged flueways, blocked secondary air inlet openings, or lack
of natural room makeup air to the oven.
BYPASS
(MINIMUM
BURNER
FLAME)
ADJUSTMENTS
A Robertshaw FDTH 300° ‐ 650° F (149° ‐ 343° C) type thermostat is used. This is a throttling type gas
thermostat with bypass flame adjustment control. For bypass adjustment proceed as follows:
1.
Preheat oven to 500° F (260° C). When thermostat has throttled to bypass the glame on the
main burner should have decreased to a flame no larger than 1/8” (6mm)
2.
If flame is too high, remove dial, insert screwdriver in screw marked “B” on the thermostat and
turn screw clockwise to lower flame.
3.
If flame is too low, remove dial, insert screwdriver in screw marked “B” on the thermostat and
turn screw counterclockwise to increase flame.