LAARS MAX 165 (DV) - Installation, Operation and Maintenance Instructions - Manual (Page 19)

MAX Oil-Fired Boiler Page 19
SECTION 4.
Operation
1. Check the boiler service switch is in the off
position.
2. Check the boiler is filled with water and the
complete system is purged of air.
3. Check the “cold fill” pressure is correct - usually
12 p.s.i.
4. Check there is ample oil in the storage tank and
all manual shut-off valves in the fuel system are
OPEN.
5. Set limit switch located in L8148A aquastat at
200º F (93°C).
6. Set manual reset limit switch at 220º F (104°C)
(Direct Vent Boilers Only).
7. Carry out burner settings, see “Preliminary
Burner Settings” (
Table 3 ).
8. Push the safety reset button on burner control and
release. Adjust room thermostat or tank aquastat
to call for heat, switch ON boiler service switch
and burner should start.
Caution
When using a direct vent system -
If smoke is seen coming from the vent terminal,
switch off burner immediately. Otherwise the outside
wall could be discolored. Check “Preliminary Burner
Settings” again.
9. On one pipe systems the pump should be bled as
soon as the burner motor starts. Bleed oil into a
container for at least 15 seconds until it is seen
to be free of air bubbles.
With two pipe suction systems, the air is returned
to the oil storage tank where it is dissipated.
10. Adjust burner to achieve the reading shown under
4B “Burner Adjustments.”
11. If burner fails to start, check “Trouble Shooting
Guide” (
Table 4 ).
4A. Preliminary Burner Settings
1. Fit the nozzle to suit firing rate required
2. Set air dial to the appropriate setting
3. Fit correct number stop pin or positioning bar to
burner.
4. Fit a pressure gauge to the fuel pump.
4B. Burner Adjustments
Test equipment required:
CO
2
analyzer Stack thermometer
Draft gauge Smoke tester
Fuel pressure gauge
Test readings should be taken from the plug in
the flue collar. Over the fire sampling is not
necessary on pressure fired boilers.
NOTE: Do not drill into the flexible vent pipe.
After firing the burner for about 5 minutes, make
the following checks and adjustments:
1.
Check the pump pressure and if necessary adjust
pressure to obtain 140 / 150 p.s.i.
2. Gradually close air dial until a slight smoke trace
is measured, then take a flue gas sample and
check CO
2
reading which should be about 13%.
3. Open air dial to reduce CO
2
by ½%, then lock
dial in this position.
NOTE: The slight increase in excess air
provides a built in margin to ensure clean combustion
throughout the heating season.
(4)
The vent pressure of the MAX DV will vary
dependent upon length of vent pipe used and the
firing rate chosen.
If pressure exceeds 0.13" W.C. recheck burner
setup for excess air / low CO
2
reading.
NOTE: With conventional chimneys the
pressure loss will be less because of the higher draft
normally generated.
5.
Flue gas temperature will vary according to the
firing rate. The following typical net
temperatures should be obtained after
approximately 15 minutes of burner operation.
Note that the temperatures listed are net
temperatures. The net temperature listed should
be compared to the measured (actual)
temperature minus the temperature of the
combustion air. (i.e. use the outside temperature
when the combustion air is ducted, and use the
room temperature when room air is used for
combustion:
320°F @ 0.75 GPH (160°C @ .75mL/s)
350°F @ 1.00 GPH (177°C @ 1mL/s)
420°F @ 1.20 GPH (216°C @ 1.20mL/s)
330°F @ 1.40 GPH (166°C @ 1.40mL/s)
410°F @ 1.65 GPH (210°C @ 1.65mL/s)
4C. Sequence of Operation
When the room thermostat or hot water tank
aquastat calls for heat the burner and circulating pump
start. The burner and pump continue to run until the
heat demand is satisfied - the hot water tank being
satisfied before the room heating requirements.
If the boiler water reaches the high limit setting of
200º F (93°C) the burner will shut off but the pump
will continue to operate to clear the residual heat.
When the boiler temperature falls the burner will
restart if there is still a demand for heat.
A manual reset high limit aquastat (set at 220ºF)
(104°C) is provided on Direct Vent Boilers to shut off
the burner in the event of a failure of the high limit
control.
The burner features a post purge timer on Direct
Vent Boilers which provides a timed overrun of the fan
to clear residual flue gases from the boiler and flue
system after combustion is shut off.