LAARS Mighty Therm HH-PH (Sizes 175-400) - Installation, Operation and Maintenance Instructions - Manual (Page 20)

LAARS HEATING SYSTEMS Page 20
Figure 31. Flame Patterns.
MAIN BURNER FLAME PATTERN
PILOT FLAME PATTERN
ELECTRONIC PILOT STANDING PILOT
temperature drop in the system. Set the hi-limit switch
15°F (8°C) above the supply temperature to the
system.
3B. Start-Up Procedure
Lighting instructions can be found on the inside
of the boiler. To start up the boiler:
1.
Make sure the system pump is running and there
is water flow.
2. Remove the control access panel (front door).
3. Set the temperature control (see Figure 30) to its
lowest setting.
4. Turn electric power to the boiler OFF.
5. Turn the manual gas valve OFF.
6. Wait 5 minutes to clear out any gas, then smell
for gas. Be sure to smell next to the floor because
some gas is heavier than air and will settle on the
floor.
7. Turn the manual gas valve ON. (For a standing
or continuous pilot system, follow the lighting
and shutdown instructions.)
8. Reset all safety devices - high limit, low water
cutoff, etc.
9. Set the temperature control to the desired setting
(see Figure 30 and section 3A).
10. Replace the control access panel.
11. Turn the electric power to the heater ON.
Caution
On a boiler equipped with the vent damper device,
the damper must be in the open position when the
main burners are operating.
If the boiler will not operate:
a.
Turn off all manual gas supply valves.
b. Turn the main electrical switch OFF.
c. Turn the gas to the boiler OFF. Follow the
instructions found on the inside of the boiler and
call a qualified professional technician or gas
supplier.
3C. Adjustment for Minimum Input Rate
(Models with Modulating Gas Valve)
Adjust the red knob on the modulating gas valve
to the dial number for the desired water temperature
(see Table 6). Adjusting the red knob to number “1”
sets the gas flow rate to minimum. The control is
factory set at “5” which is satisfactory for most
installations.
Temp.
Dial No. °F °C
1 140 60
2 152 67
3 165 74
4 177 81
5 190 88
6 202 94
7 215 102
8 227 108
9 240 116
Table 6. Modulating Valve Temperature Setting.
3D. Hi-Limit Switch Checkout
After running the boiler for a long enough
period, bring the water temperature within the range of
the hi-limit switch and slowly back off the hi-limit
setting until the boiler shuts off. The main burners
should re-ignite when the hi-limit switch is reset and
turned back up to its original setting. The boiler
should now run until it shuts off automatically on
operating control.
When all the safety shut-off devices have been
tested, refer to Section 3A for the proper settings of
the temperature controls.