Checking Main Burners; Checking Orifices; Checking Gas Pressure - Daikin M Series Service And Troubleshooting

SERVICING
White Rodgers Model 36G54 (Two Stage)

Checking Main Burners

The main burners are used to provide complete
combustion of various fuels in a limited space, and transfer
this heat of the burning process to the heat exchanger.
Proper ignition, combustion, and extinction are primarily
due to burner design, orifice sizing, gas pressure, primary
and secondary air, vent and proper seating of burners.
Beckett Burner
Disconnect Gas and electrical power supply.
In checking main burners, look for signs of rust, oversized
and undersized carry-over ports restricted with foreign
material, etc.

Checking Orifices

A predetermined fixed gas orifice is used in all of these
furnaces. That is an orifice which has a fixed bore and
position.
WARNING
The length of Dimension "A" determines the angle of Gas
Stream Defraction, "B".
A dent or burr will cause severe deflection of gas stream.
No resizing should be attempted until all factors are taken
into consideration such as inlet manifold gas pressure,
alignment, and positioning, specific gravity and BTU
content of the gas being consumed.
The only time resizing is required is when a reduction in
firing rate is required for an increase in altitude.
Orifices should be treated with care in order to prevent
damage. They should be removed and installed with
a box-end wrench in order to prevent distortion. In no
instance should an orifice be peened over and redrilled.
This will change the angle or deflection of the vacuum
effect or entraining of primary air, which will make it difficult
to adjust the flame properly. This same problem can occur
if an orifice spud of a different length is substituted.
Disconnect Gas and electrical power supply.
1. Check orifice visually for distortion and/or burrs.
2. Check orifice size with orifice sizing drills.
3. If resizing is required, a new orifice of the same
physical size and angle with proper drill size opening
should be installed.

Checking Gas Pressure

Gas inlet and manifold pressures should be checked and
adjusted in accordance to the type of fuel being consumed.
Disconnect Gas and electrical power supply.
A
GAS
STREAM B
DENT OR
BURR
GAS
STREAM B
WARNING
WARNING
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