LAARS Mascot LX MLXC 175 MBH - Install and Operating Manual - Manual (Page 44)

LAARS Heating Systems Page 40
4. Mascot LX will enter the start sequence. Blower
and pump will energize for pre-purge, then the
ignition sequence starts. After all safety devices
are verified, the gas valve opens. If ignition doesn’t
occur, turn off the Mascot LX, check that there is
proper gas supply. Wait 5 minutes and start the unit
again.
5. Turn Mascot LX on.
6. After placing the appliance in operation, the
Burner Safety Shutoff Device must be tested:
(a) Close gas shutoff valve with burner operating.
(b) Flame will go out and blower will continue to run
for the post purge cycle. One or three additional
attempts to light will follow including pre-purge,
ignitor on, valve/flame on and post purge. Ignition
will not occur as the gas is off. The ignition control
will lockout.
(c) Open gas shutoff valve. Reset the boiler control
by pressing the RESET button on the control or
on the display. Restart the appliance. The ignition
sequence will start again and the burner will start.
The appliance will return to its previous mode of
operation.
CAUTION
Should any odor of gas be detected, or if the gas
burner does not appear to be functioning in a normal
manner, CLOSE MAIN SHUTOFF VALVE. Do not
shut off switch. Contact your heating contractor, gas
company, or factory representative.
10.2.2 Boiler Setup and Adjustment
1. Measure the CO
2
in the flue products at high fire.
The Mascot LX can be forced to high fire to allow
for easier setup. Refer to Section 8 for instructions
on how to access the forced rate menu. The CO
2
readings should be between the range shown in
Table 17 . If the CO
2
is not within the range shown,
adjustments may be made. To adjust the high fire
CO
2
, locate the high fire adjuster screw (see Figure
26 ). Using a 2.5 mm Hex wrench, slowly make
adjustments in 1/16 of a revolution increments
until the CO
2
is within the range identified.
(see Figure 26 )
2. Measure the CO
2
in the flue products at low fire.
Mascot LX can be forced to low fire to allow for
easier setup. Refer to Section 8 for instructions on
how to access the forced rate menu. CO
2
readings
should be between the range shown in Table 17 . If
the CO
2
is not within the range shown, adjustments
may be made. To adjust the low fire CO
2
, locate
the low fire adjuster screw. Using a 4 mm Hex
wrench, slowly make adjustments in 1/16 of a
revolution increments until the CO
2
is within
the range identified. (see Figure 26 )
3. Repeat steps 1 and 2 to confirm that the CO
2
ranges
are within the required ranges. High and Low
Fire CO2 settings should be approximately equal.
Adjust if necessary.
If any CO2 readings cannot be adjusted to the
specified ranges (see Table 17) , please consult the
factory for further information.
WARNING
Improper adjustment may lead to poor combustion
quality, increasing the amount of carbon monoxide
produced. Excessive carbon monoxide levels may
lead to personal injury or death.
10.3 Shutting Down Mascot LX
1. Turn off the main electrical disconnect switch.
2. Close all manual gas valves.
3. If freezing is anticipated, drain Mascot LX and be
sure to also protect building piping from freezing.
All water must be removed from heat exchanger
and condensate trap or else damage from freezing
may occur.
This step to be performed by a qualified service person.
10.4 To Restart Mascot LX
If drained, go back to Section 10 in this manual for
proper filling and purging, prior to continuing.
1. Turn off the main electrical disconnect switch.
2. Close all manual gas valves.
3. WAIT FIVE (5) MINUTES.
4. Set the aquastat or thermostat to its lowest setting.
5. Open all manual gas valves.
6. Reset all safety switches (pressure switch, manual
reset high limit, etc.).
7. Set the temperature controller to the desired
temperature setting and switch on electrical power.
8. Burner will go through a prepurge period and
ignitor warm-up period, followed by ignition.