Daikin DBG Series Installation Instructions Manual page 21

The pressure regulator on LP gas models is adjusted for
10.0" w.c. manifold pressure and is intended to prevent
over-firing only. Do not attempt adjustment of the built-in
pressure regulator unless the supply pressure is at least
7.0" w.c. on natural gas or 14.0" w.c. on propane gas.
Check the location of the ignition electrode and the flame
sensor for correct gap setting.
flame sensor and ignition electrode location
MAXIMUM NUMBER
MAXIMUM
INPUT of
BTUH/BURNER
(BTUH) BURNERS
210,000 7
heat exchanger and burner orifice specifications
NOTE: Gas appliances located more than 2000 feet
above sea level must be derated 4% per 1000 feet
of total elevation and that variance in gas heating
value and specific gravity require change in
manifold pressure to obtain rating, it is mandatory
that the input be adjusted at the installation site.
All installations should be made as outlined in
the latest edition of the National Fuel Gas Code
ANSI Z223.1,section "Procedures To Be Followed
To Place An Appliance in Operation". Refer also
to the "User's Information Manual" supplied with
the unit for additional information on the gas
furnace.
Gas Supply And Manifold Check
Gas supply pressure and manifold pressure with the
burners operating must be as specified on the rating plate.
Gas Inlet Pressure Check
Gas inlet pressure must be checked and adjusted in
accordance to the type of fuel being consumed.
With Power And Gas Off:
1. Connect a water manometer or adequate gauge to
the inlet pressure tap of the gas valve.
GAS ORIFICES
NATURAL PROPANE
(Dia) (LP) (Dia)
30,000 #37
Inlet gas pressure can also be measured by removing the
cap from the dripleg and installing a predrilled cap with a
hose fitting.
With Power And Gas On:
2. Put unit into heating cycle and turn on all other gas
consuming appliances.
NATURAL
PROPANE
NOTE: Inlet gas pressure must be within limits
shown above.
If operating pressures differ from above, make necessary
pressure regulator adjustments, check piping size, etc.,
and/or consult with local utility.
Manifold Pressure Check and Adjustment
The gas valve has a pressure tap to facilitate measurement
of the manifold pressure. The manifold pressure must be
measured with the burners operating.
1. With disconnect switch open, remove field connected
thermostat wire from terminal R, W1 and W2 on TB1.
Place jumper wire between R, W1 and W2 to engage
high stage heat.
2. See Figure in gas input check section for gas valve
adjustment.
#55
To adjust the pressure regulator, remove the adjustment
screw cover on the gas valve. Turn the adjustment screw
out (counterclockwise) to decrease pressure, turn in
(clockwise) to increase pressure. Only small variations
in gas flow should be made by means of the pressure
regulator adjustment. Any major changes in flow should
be made by changing the size of the burner orifices. The
measured input rate to the furnace must not exceed the
rating specified on the unit rating plate.
For natural gas, the high stage manifold pressure must be
between 3.2 and 3.8 inches water column (3.5 nom inal).
Low stage manifold pressure must be between 1.7 to 2.3
inches water column (2.0 nominal).
3. To set low fire rate, open disconnect switch and
remove jumper from R to W2. To set low fire manifold
pressure, repeat steps above. Refer to Figure in gas
input check section for location of high and low stage
pressure adjustment.
For propane gas, the manifold pressure must be between
9.7 and 10.3 inches water column (10.0 nominal). Low
stage manifold must be between 5.7 and 6.3 inches water
column (6.0 nominal).
Gas Input (Natural Gas Only) Check
It is the responsibility of the contractor to adjust the gas
input to the unit.
21
INLET GAS PRESSURE
Mi n. 5.0" W.C., Ma x. 10.0" W.C.
Mi n. 11.0" W.C., Ma x. 14.0" W.C.