Checking Main Burners; Checking Orifices - Daikin DBG Series Service Instructions Manual

SERVICING
Regulator Cover Screws
(Reg. Adj. Beneath these screws)
INLET
Gas Valve
On/Off Switch
WHITE-RODGERS 36H54 PRESSURE
ADJUSTMENTS
HONEYWELL 0151M00015 PRESSURE
ADJUSTMENTS
S-305 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
High Fire
Disconnect gas and electrical power supply.
Adjust
Low Fire
Adjust
In checking main burners, look for signs of rust, oversized and
undersized carry-over ports restricted with foreign material, etc.
OUTLET
S-306 CHECKING ORIFICES
A predetermined fixed gas orifice is used in all of these fur-
naces. That is an orifice which has a fixed bore and position.
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.
WARNING
A
STREAM B
DENT OR
BURR
WARNING
GAS
GAS
STREAM B
45