Daikin FC Series, Руководство по установке и обслуживанию

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Figure 8: RM7897A Flame Safeguard
Low Fire Start
Modulating burners are controlled for low fire start. The
modulating gas valve actuator will position the gas valve to the
low fire position each time the burner is to light.
Pilot Start-Up
Open the pilot gas cock (gas test cock remains closed) and
position the switch to AUTO to start the burner motor . After 30
(or 90) seconds the pilot valve opens (as indicated when the
indicator LED marked PILOT comes on) and the pilot should
ignite. The flame signal should read 1.5 to 5.0 volts DC. The
LED marked MAIN should come on when the pilot flame has
been detected by the flame safeguard and it has energized the
main gas valve . On the initial start-up, if the pilot does not light
and the flame safeguard locks out, reset it and make several
attempts to light the pilot before assuming problems other than
more air in the gas lines . If the initial pilot operation is erratic, it
may be well to wait until after a period of main flame operation
has further purged the gas lines before trying to “adjust out”
something that may actually be air in the lines . If the burner
is equipped for modulation or two-stage operation, observe
the flame signal reading at all firing positions. Cycle the flame
safeguard to determine that the burner goes to the low fire
position for light off and that the pilot will ignite and operate.
See Service, page 16 for pilot adjustments, etc .
Main Flame Start-Up
1 . At the conclusion of the pilot start-up and with the gas
test cock closed, measure the air box pressure (see
Table 10 on page 36 ) by holding a rubber manometer
tube tightly over the burner air pressure port . The tube
must surround the hole and seal tightly against the
door to measure the static pressure through the hole .
Modulating burners are to be at their “high fire” position
for this measurement . Table 10 , Column 8, indicates
typical readings and any appreciable deviations from
these would indicate a burner air problem that should be
found before attempting to fire the unit. These problems
could include linkage adjustments disturbed during
shipment, etc .
2 . With control switch at OFF, connect the manometer to
the main manifold pressure tap and open the gas test
cock .
3 . Position the switch to AUTO and the unit will go through
the prepurge cycle, the pilot will light, and the main
flame will come on. Watch the manometer during the
light off attempt. The manifold pressure should rise
to about 90% of the specified value within 2 seconds
and the main flame should ignite immediately when
the pressure approaches this value . If the burner has
not lit within a few seconds after pressure is indicated
on the manometer, shut down the unit and check for
problems (refer to the Troubleshooting Chart, page
26 ) . Modulating burners should have their controllers
set to call for high fire although they will have a forced
low fire start. If combustion appears normal, proceed with
combustion tests .
4 . Combustion tests . These tests should be run after the
furnace has been running 10 to 15 minutes .
a . Check input: See Verify Input Rate on page 18 .
b . Check CO
2
: See Check CO
2
, CO & Stack
Temperature on page 19 .
c . Check CO: See Check CO
2
, CO & Stack
Temperature .
5 . On modulating burners, cycle the burner from high to low
fire, observing flame and repeating CO
2
and CO tests at
low fire after burner has been running 10 to 15 minutes.
6 . Cycle the unit through several start-ups with controls
calling for first low fire and finally high fire. Watch for any
indications that the unit is not operating as expected, and
for inconsistencies that could indicate future problems .
Start-Up and Operating Procedures
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