S7999B SYSTEM DISPLAY
23
65-0283—2
12.c.
Press Purge button.
A “P” will be displayed on the profile.
The R7999 will energize its HFP output (terminal 10)
which, in turn, allows the burner control to start the
purge time. Wait for purge to complete and cursor to
move to preset Lightoff position.
12.d.
Press the Open and Close buttons for Fuel and Air and the FGR
(if present) to move the cursor to the desired Lightoff point of the
burner.
The damper will automatically move to a 25% open
position, while the fuel actuator will remain at the
closed position plus 1 degree if it is unconfigured.
When used with Honeywell burner controls, the user
has 240 seconds to perform this action, otherwise the
burner control will lock out.
12.e.
Press Lightoff button.
An “L” will be displayed on the profile, and the R7999
will energize the LFP output (terminal 8), which will
allow the burner control to light off the system.
The burner should light. Wait for the lightoff to
complete and the system to change to the Modulating
state.
12.f.
Press Open and Close for Fuel and Air and the FGR (if present)
to move the cursor to the Minimum Modulation point for the
burner.
12.g.
Press Min button.
An “m” will be displayed on the profile.
NOTE: The min modulation point may be higher or
lower than the Lightoff point.
12.h.
Press Open and Close for Fuel and Air and the FGR (if present)
to move the cursor to the next desired fuel air mixture point.
The R7999 enforces slope limitations of 1 to 8 and 8
to 1 (in degrees) with the exception of Flat Line or
Negative FGR capability. The cursor changes from a
cursor to a box when you have moved out of the
range of allowable slopes. You are not allowed to
enter points when a box shape is present.
With controller release 1.4 or greater, the FGR
actuator may have negative slopes (maximally
negative slope of 1 to 5) anywhere within the
modulation band.
12.i.
Press Point button.
Or press Maximum Modulation.
With Rev. 1.4 controllers or greater, the user may alternatively
place a maximum modulation point in place of an intermediate as
long as a span of at least 17 degrees exists between the
minimum and maximum modulation points.
A dot will be displayed on the profile and a line will
connect the minimum modulation point and the first
intermediate point.
Entering a new Maximum Modulation point causes an
pre-existing Maximum Modulation point to change to
an intermediate point. This technique of entering each
new intermediate point as the new “temporary”
Maximum Modulation point has an advantage, which
is apparent under light boiler load conditions. The
user will be able to use the “Move Along Curve”
commands during the next lightoff sequence and
hence will be able to more quickly reach the firing rate
point where the system was at prior to going out
because of low demand.
For gas systems where the gas pressure has not
been adjusted to match the burner-rated BTU
capability, the use should use the maximum
Modulation replacement technique to rough in a curve
until maximal airflow is obtained. The gas flow may
then be adjusted to set the maximum firing rate. The
user may then delete all points and immediately
re-enter another maximum modulation point.
12.j.
Repeat steps 12.h. and 12.i. until you have created at least six
points starting with Min.
R7999 builds 185 and higher require only Min,
Lightoff and Max.
Table 4. Commissioning Overview. (Continued)
Step
Action
Notes
