LAARS Mighty Stack MS-080 (Sizes 199, 300, 399) - Install and Operating Manual - Manual (Page 22)

Laars Heating Systems Page 22
9. After placing the appliance in operation, the
Burner Safety Shutoff Device must be tested.
To test:
(a) Close gas shutoff valve with burner
operating.
(b) The flame will go out and blower will
continue to run for the post purge cycle.
Three attempts to light will follow. Ignition
will not occur as the gas is off. The ignition
control will lockout, and will have to be
reset by cycling the power before the unit
will operate.
(c) Open gas shutoff valve. Restart the
appliance. The ignition sequence will
start again and the burner will start. The
appliance will return to its previous mode
of operation.
6.6.2 High Altitude Adjustment and
Set-Up
High altitude adjustment must not be made on
appliances operating at elevations below 2500 ft. (762 m).
No orifice changes are required to adjust the
Mighty Stack appliances for high altitude. High
altitude adjustment is accomplished by adjustment
of the air shutter. A CO
2
or O
2
analyzer is required to
make these adjustments.
Start the adjustment process by checking the CO
2
in the “as installed” condition. Adjust the air shutter(s)
so that the CO
2
is about 8% or the O
2
is about 6.8%
for appliances operating on natural gas. For appliances
operating on LP Gas adjust the air shutter(s) so that the
CO
2
is about 9.2% or the O
2
is about 6.8%.
If the appropriate CO
2
/ O
2
levels cannot be
achieved by adjusting the air shutter. Contact the
Technical Services Department at number shown on
back page.
The amount of derate will vary depending on
heating value of the fuel and the elevation at the
installation site.
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, and contact your heating contractor,
gas company, or factory representative.
Attention
Si vous sentez une odeur de gaz ou si le brûleur
à gaz ne parait pas fonctionner de manière
normale, fermez la vanne d’isolement, ne fermez
aucun interrupteur, et appelez votre entreprise de
chauffage, la compagnie de gaz ou un représentant
du fabricant.
6.7 Shutting Down the Mighty Stack
1. Switch off the main electrical disconnect switch.
2. Close all manual gas valves.
3. If freezing is anticipated, drain the Mighty Stack
and be sure to also protect building piping from
freezing.
This step to be performed by a qualified
service person.
6.8 To Restart the Mighty Stack
If drained, follow Section 6.1 in this manual for
proper filling and purging.
1. Switch 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 pre-purge period and
ignitor warm-up period, followed by ignition.