IRIS P522 manual Setup and Adjustment, Procedures, Initial Setup, Sighting Adjustment

IRIS MODEL P522 APPLICATION MANUAL

SETUP AND ADJUSTMENT	pipe and the diameter of the sight pipe is large enough
PROCEDURES	to allow a range of angles to be viewed (see section
	ANGLE OF VIEW OF VIEWING HEAD).
Multiburner applications require the most care in
adjustments to ensure proper flame out operation	As a general rule, the sighting of the S506 viewing
under worst-case conditions (refer to previous sec-	head is more likely to be “line-of-sight” than the S512
tion MULTIBURNER REQUIREMENTS).	infrared flicker viewing head, which will read flame
These same procedures can be followed for single-	signals bouncing off the side of the sight pipe and
burner applications, even though the adjustment re-	other “reflectors.” Sometimes, the reading with the
finements described here may not be necessary.	IR detectors can be greater with a reflective signal
There are two, basic worst-case conditions in a	than the direct line of sight. The UV viewing head,
	on the other hand, will have to be aimed at the part
multiburner installation:
	of flame having the highest concentration of UV
One is the initial light off of other burners	which is usually at the root of the flame (at the throat
	of the burner) and in a very narrow range.
after the first burner has been established
(particularly if the established burner, or	The angle of view of the S506 is somewhat wider
burners, has a flame envelope that over-
	than the S512 or S509, but this does not offset the
laps the trial burner sighting). If there is a
	fact that the UV radiation present is very narrow.
flame out or ignition failure of this burner
	This is not true, however, for low NOx gas burners;
(or its igniter) during this startup sequence,
	the UV is usually much less in intensity with this
the flame monitor must detect this condi-
	type of burner, and spreads out in front of the burner,
tion – meaning that it must discriminate
	getting readings from all over the furnace when many
between the lack of flame and the back-
	burners are on. This is particularly true when fuel
ground flame of the established burner.
	gas recirculation is used.
This would represent “flame discrimina-
tion under low fire conditions.”	Another factor to consider when aiming the viewing
Second would be when the fired unit is in	heads is the load condition of the boiler. The flames
	from a burner can be radically varied at different
a high fire condition (i.e., all burners are
	loads – one of the reasons for trying to select a sight-
firing at maximum rate, when suddenly
	ing that will minimize the changing flame at differ-
one burner flames out – possibly because
	ent loads. If the flame front moves farther away at
of a clogged oil gun or some other type of
	higher loads, then a sighting parallel to the burner
fuel disruption). This is also a dangerous
	axis will be best. A large-diameter sight pipe with a
condition, particularly for two- to four-
	swivel mount is recommended for all installations
burner installations. The flame monitor
	on large, multiburner boilers. (Refer to Figure 20.)
must detect this flamed out burner so the
	INITIAL SETUP
fuel valve (safety shutoff valve) supply-
ing this burner will close. This means that	A. The initial settings for the P522 signal
the flame OFF threshold for this flame
	processor should be as follows:
monitor must be set above the signal level
produced by the other burners that are in a	1. F.F.R.T. (Time Delay Off) to 3 SEC.
high-fire condition.	2. GAIN SET to 25.
SIGHTING ADJUSTMENT	3. TIME DELAY ON to 0.
Before making definitive settings (i.e., establishing
	4. FLAME ON to 200.
the set points) for flame ON/OFF, you must opti-
mize the sighting of the viewing head. This can be	5. FLAME OFF to 100.
done if a swivel joint is used at the end of the sight
Page 16